Neuro-Oncology
Neuro-Oncology 17(10), 1322 – 1332, 2015
doi:10.1093/neuonc/nov119
Advance Access date 22 July 2015
Intratumoral heterogeneity in glioblastoma: don’t forget
the peritumoral brain zone
Jean-Michel Lemée, Anne Clavreul, and Philippe Menei
Department of Neurosurgery, University Hospital of Angers, Angers, France (J.-M.L., A.C., P.M.); INSERM U1066, “Micro- et
nano-médecine biomimétiques”, Angers, France (J.-M.L., A.C., P.M.)
Corresponding Author: Pr Philippe Menei, MD, PhD, Department of Neurosurgery, University Hospital of Angers, 4, rue Larrey 49933 Angers
Cedex 09, France ([email protected]).
Glioblastoma (GB) is the most frequent and aggressive primary tumor of the central nervous system. Prognosis remains poor despite ongoing progress. In cases where the gadolinium-enhanced portion of the GB is completely resected, 90% of recurrences
occur at the margin of surgical resection in the macroscopically normal peritumoral brain zone (PBZ). Intratumoral heterogeneity
in GB is currently a hot topic in neuro-oncology, and the GB PBZ may be involved in this phenomenon. Indeed, this region, which
possesses specific properties, has been less studied than the core of the GB tumor. The high rate of local recurrence in the PBZ and
the limited success of targeted therapies against GB demonstrate the need for a better understanding of the PBZ. We present here
a review of the literature on the GB PBZ, focusing on its radiological, cellular, and molecular characteristics. We discuss how intraoperative analysis of the PBZ is important for the optimization of surgical resection and the development of targeted therapies
against GB.
Keywords: glioblastoma, histology, omics, peritumoral brain zone, radiology, targeted therapies.
Glioblastoma (GB) is the most frequent and aggressive primary
tumor of the central nervous system (CNS). Its incidence varies
depending on the country and the population, with 4.96 cases
per 100 000 inhabitants per year.1 Despite ongoing progress in
the therapeutic management of GB, prognosis remains poor,
with an overall survival of 14– 15 months after complete surgical resection and adjuvant radiochemotherapy.2 Typically, radiological recurrence occurs 6 – 7 months after surgery,
quickly followed by clinical relapse.
The heterogeneity of GB is a hot topic in neuro-oncology. The
interindividual heterogeneity of GB has been well known since
the pioneering work of Burger and Kleihues,3 – 7 and several
studies have even described intratumoral heterogeneity inside
GB at the cellular and molecular level.6,8,9 This intratumoral
heterogeneity may lead to a different Verhaak subtype in 2
different samples from the same tumor, or it may even give
rise to differences at the cellular level as shown by Patel et al
(2014).6,10 – 12 GB intratumoral heterogeneity may influence
tumor aggressiveness or response to chemotherapies such as
temozolomide.8,13
Intratumoral heterogeneity is not only limited to the tumor,
it also involves the peritumoral brain zone (PBZ), which possesses specific properties that contribute to GB heterogeneity. Few
studies have focused on the PBZ and its microenvironment,
despite the fact that 90% of recurrences occur in this area.14
We present here a review of the PBZ of GB, focusing on its radiological, cellular, and molecular characteristics based on current
literature and our findings obtained during the Grand Ouest Glioma Project, a translational research project on intratumoral
heterogeneity that we recently conducted.12,15 – 24 We also
highlight perspectives for future research on the PBZ that
may facilitate the development of new targeted therapies
against GB and the optimization of surgical resection.
Characteristics of the Glioblastoma
Peritumoral Brain Zone
Radiological Aspect
The PBZ is usually defined radiologically as the brain area surrounding the tumor without contrast enhancement in T1
gadolinium-enhanced 3-dimensional (3D) magnetic resonance
imaging (MRI). This region is often hyperintense in T2-weighted
(especially T2- fluid-attenuated inversion recovery) acquisition,
which reflects vasogenic edema in the vicinity of the tumor and
suggests tumor infiltration. This definition of the PBZ delimits
an area of several centimeters in width around the tumor,
which is the site of tumoral invasion and specific molecular,
Received 11 March 2015; accepted 10 June 2015
# The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved.
For permissions, please e-mail: [email protected].
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Lemée et al.: The peritumoral brain zone in glioblastoma
radiological, and cellular alterations that are not limited to the
immediate zone surrounding the contrast-enhanced tumor.
We chose this radiological definition of the PBZ because GB-cell
infiltration may be several centimeters deep,25,26 such that molecular alterations of the parenchyma may be located more than
1 centimeter from the contrast-enhancing lesion.12,15,17,18,23
A lack of contrast enhancement with gadolinium-based
contrast agents during MRI of the PBZ does not necessarily indicate the absence of tumor cells in this area because a minimum concentration of tumor cells in the PBZ is necessary to
produce detectable alterations on MRI. Various preoperative
MRI sequences can be used to search for tumor infiltration in
the PBZ. For example, an increase of the apparent diffusion coefficient (ADC) in the PBZ, which measures the magnitude of
water molecule diffusion, is correlated with tumor cell infiltration.27 – 30 In dynamic contrast enhancement (DCE) MRI analysis, the volume transfer coefficient k trans, which is associated
with the microvascular permeability of gliomas, is the most
sensitive and specific predictor of brain infiltration and histological grading.23,31 Two recent studies also showed that DCE MRI
parameters in specific areas of GB, including the PBZ, are correlated with biomarkers of hypoxia and overall patient survival.32,33 Furthermore, the role of diffusion tensor imaging
(DTI) was discussed in a recent review, describing an inverse correlation between fractional anisotropy and infiltration of the
PBZ.34,35 One study proposed a tumor infiltration index based
on the ratio between the expected and the observed fractional
anisotropy to investigate tumor-cell infiltration in the PBZ,36 although this index may not be useful for assessing tumor infiltration in patients with peritumoral vasogenic edema.37
Furthermore, residual and central GB cells respond differently
to drug and irradiation challenges in vitro. 25 Glas et al (2010)
and 2 other studies using 5-aminolevulinic acid-assisted surgery found that residual GB cells have a lower capacity for selfrenewal than central GB cells.25,39,42 Several genes may distinguish residual GB cells from central GB cells,25,40,41 including
genes involved in the stem cell phenotype (CD133, Sox2, nestin,
musashi 1), invasion (Galectin-1, Rac1, Rac3, RhoA GTPases,
p27, avb3 integrin), cell adhesion (CDH20, PCDH19), migration
(SNAI2, NANOG, USP6, DISC1), immune or inflammatory responses (TLR4), and blood vessel formation (HEG1, VEGFR2).
The identification of these genes has opened new lines of research to improve the understanding of the molecular features
promoting the dissemination and progression of GB.
Reactive Astrocytes
Astrocytes are star-shaped glial cells in the CNS with several
important functions including synaptic transmission and information processing.43 Many studies have shown that reactive
astrocytes are located around GB cells, but their role in GB
progression is not completely understood. Reactive astrocytes
promote tumor growth and survival44,45 and stimulate the metastasis of breast and lung cancer cells to the brain by secreting
various cytokines.45,46 Astrocytes also enhance the invasive potential of GB cells by producing neurotrophic factors such as
TGF-a, CXCL12, S1P, and GDNF.47,48 Astrocytes also strongly express IL1b and may be involved in immune reactions against
the tumor.49
Inflammatory Cells
Cellular Content
Tumor Cells
The PBZ shares the same macroscopic aspect as normal brain;
however, it is well established that GB cell infiltration extends
well beyond the radiological limits of the tumor into the macroscopically normal PBZ, suggesting that GB should be considered a systemic brain disease and not a delineated tumor.5,7,38
GB cells invade the brain via the same extracellular routes used
by neural cells along existing structures such as blood vessels
and white matter tracts.38 GB cells in the PBZ are typically identified by microscopy with hematoxylin-phloxin-saffron (HPS)
staining and/or immunohistochemistry using anti-p53 and
anti-Ki-67 antibodies. We recently analyzed 28 GB PBZ biopsies
stained with HPS, and we found tumor cell infiltration in one
third of the samples.23 We also performed DNA index analysis
by flow cytometry on 25 of these PBZs. Eight (32%) displayed
aneuploid cells, which made up between 3% and 44% of the
samples. Interestingly, the PBZ of 4 patients contained some,
but not all, of the aneuploid cell populations identified in their
corresponding tumor zone, suggesting that not all tumor
clones are able to migrate away from the tumor core. Accordingly, the infiltrating GB cells in the PBZ were recently characterized using primary cell cultures and were shown to differ
phenotypically from those isolated from the corresponding
mass.25,39 – 41 In particular, residual GB cells (ie, those located
at the resection margin) proliferate more quickly and are
more invasive than GB cells in the tumor center.25,40
Neuro-Oncology
Many studies have identified inflammatory cells in the GB tumor
core, particularly tumor-associated macrophages (TAMs) and
microglia.50,51 More TAMs are present in GB (grade IV) than in
grade II or III gliomas, and their numbers are strongly correlated
with intratumoral vascular density.52 Although the abundance
of TAMs per se is not associated with the differential survival of
GB patients, their activation state (M1 or M2) has some prognostic value.53 – 55 Specifically, TAMs that have differentiated into M2
macrophages act as protumoral macrophages and contribute to
disease progression. TAMs are now emerging as a promising target for new adjuvant therapies for GB.51,56
Although many studies have focused on the inflammatory
cells present in the GB tumor core, only one study (conducted
by Parney et al in 2009) has investigated inflammatory cells in
the PBZ.57 In this study, macrophage-like cells were the most
common infiltrating inflammatory cells in the PBZ, followed
by microglia-like cells and lymphocytes. These inflammatory
cells were also less common in the PBZ than in the GB tumor
core. It is not currently known whether macrophage-like cells
present in the PBZ share characteristics with the TAMs found
in the GB tumor core.
Other Stromal Cells
We have isolated, from histologically normal GB PBZ, another
population of stromal cells, which we named GB-associated
stromal cells (GASCs). GASCs are diploid, do not display the genomic alterations typical of GB cells, and share phenotypic and
1323
Lemée et al.: The peritumoral brain zone in glioblastoma
functional properties with cancer-associated fibroblasts (CAFs)
that have been described in the stroma of carcinomas. In particular, GASCs express markers associated with CAFs such as alpha
smooth-muscle actin (a-SMA), platelet-derived growth factor
receptor-beta (PDGFRb), S100A4/FSP1, and CD146. They have
angiogenic properties and tumor-promoting effects on GB cells
in vitro and in vivo. 15,16 In a recent study, we showed that 2
extratumoral microenvironments are present in GB patients: an
extratumoral microenvironment containing GASCs with procarcinogenic properties and another containing GASCs without such
properties.16 Interestingly, Roman-Perez et al (2012) also identified 2 different subtypes of extratumoral microenvironment influencing the aggressiveness and outcome of human breast
cancers.58 Thus, the subtype of GASCs present after resection
may determine the likelihood and timing of GB recurrence. The
origin of GASCs is unknown; however, we showed that these
cells share several properties with mesenchymal stem cells
(MSCs), suggesting that GASCs are derived from these cells.15
Molecular profile
Immunohistochemistry
Various immunohistochemical studies of the PBZ suggest that
the peritumoral compartment undergoes substantial modifications regarding vascularization and other biomolecular features.
For example, markers of neovascularization (eg, CD105, nestin,
phosphorylated extracellular signal-regulated kinases, and
c-Jun NH2 terminal kinases [JNKs]) are expressed in the PBZ, irrespective of the presence of tumor cells.59 – 61 In addition, the
expression of CD105, JNK, and nestin in the PBZ is associated
with poor prognosis.59,60 Jensen et al (2014)32 analyzed molecular markers of hypoxia in the PBZ and found that lower VEGF
expression was predictive of longer progression-free survival.
The abundance of adenosine A1 receptors and STAT1 expression
are also higher in the PBZ than in the GB and normal brain samples.62,63 These modifications may have neuroprotective effects
against GB progression. Indeed, STAT1 is a well-known tumor
suppressor protein that acts via the JAK-STAT pathway, and gliomas grow faster in adenosine A1 receptor-deficient mice than
in control mice.63,64 The immediate vicinity of the GB is also characterized by high levels of copper and zinc,62 but the pathophysiological effect of these changes is unknown.
“Omics”
Molecular biology has made substantial progress in the past few
years, with the development and simplification of “omic” analyses including genomic, transcriptomic, and proteomic analyses.
Following these analyses, several molecular classification systems for GB were proposed, which have enabled the identification of specific subgroups of GB differing in terms of clinical
features, disease progression, and response to adjuvant therapies. The most known is the Verhaak classification system,
which is based on a signature of 840 genes that divide GB into
proneural, neural, classical, and mesenchymal subtypes.65 More
recently, Sturm et al (2012)66 also proposed a clinically relevant
molecular classification system based on IDH1 and H3F3A mutations. These omic analyses have been mostly performed on
1324
the GB tumor core, although we recently conducted such an
analysis on 10 PBZs during the Grand Ouest Glioma Project.23
Genomic analysis of these 10 PBZs found no genomic alterations in the 6 PBZs considered free of tumor infiltration in histopathological analysis, whereas their corresponding tumor
zone presented genomic alterations typical of GB including
loss/partial loss of chromosome 10, focal deletion of the
CDKN2A/B locus, polysomy of chromosome 7, and focal amplification of EGFR. Genomic alterations were present in the 4 PBZs
showing tumor cell infiltration in histopathological analysis,
comprising some but not all of the alterations found in their
corresponding tumor zones. These PBZs contained classical alterations found in GB, like chromosome 7 polysomy, EGFR amplification, and chromosome 10 deletion, although CDKN2A/2B
deletion was rare. This result suggests that chromosome 7 and
10 alterations are downstream events in GB tumorigenesis and
that some, but not all, tumor clones are able to migrate from
the tumor core to the PBZ, as described above. These results are
consistent with the recent work of Mangiola et al (2013), who
identified cells with an EGFR amplification in the PBZ.67
The transcriptomic and proteomic analyses that we conducted on these 10 PBZs revealed an intratumoral gradient of
gene expression from the tumor core to the PBZ.12,17 The transcriptomic analysis also indicated that the PBZ has a proneural
or neural profile, regardless of the adjacent GB subtype.12 Gill
et al (2014) 68 described similar results and demonstrated
(with a larger cohort) that the PBZ in the proneural GB subtype
strongly express oligodendrocyte progenitor genes, whereas
the PBZ in the mesenchymal GB subtype strongly expresses astrocytic and microglial genes.
We were unable to identify a specific molecular signature of
the PBZ with “omic” analyses because of interpatient heterogeneity in these 10 PBZ samples. A large cohort of PBZ samples is
thus necessary to identify such a molecular signature, but the
constitution of this cohort raises the ethical issue of sampling
normal brain tissue around the tumor. Furthermore, the identification of such a signature is complicated by the choice of the
control brain sample to be used. Samples from epilepsy patients undergoing brain surgery (EB samples) are commonly
used as a control in proteomic or transcriptomic studies. However, we recently showed that EB samples display a tumor-like
expression pattern and are not a suitable control for studying
the proteomic or transcriptomic profile of the PBZ.18 Mangiola
et al (2013) studied the gene expression profile of the PBZ
using control tissue obtained from patients operated on for
deep cavernomas with radiological signs of recent bleeding.67
They identified 57 genes that were significantly differentially
expressed between PBZ and control brain samples. Genes associated with growth and proliferation and cell motility/adhesion
were overexpressed, whereas those involved in neurogenesis
were largely underexpressed in the GB PBZ. However, only 4
PBZ samples were included, and more PBZ samples are required
to identify a molecular signature of this area able to predict the
clinical outcome of GB patients.
Piwecka et al (2015) recently compared global microRNA
(miRNA) expression in adult malignant gliomas (mainly GBs),
the tumor margin, and nontumor brain tissues.69 They found
that the expression of 97 miRNAs differed significantly between
GB and normal brain and that 22 miRNAs were differentially expressed between the border of the tumor and normal brain. Of
Lemée et al.: The peritumoral brain zone in glioblastoma
note, miR-625 was downregulated in the border of the tumor
but not in the GB samples, suggesting that some alterations
are specific of the PBZ. Several studies have shown that miRNAs
play a role in GB growth by influencing stem cell behavior and
that these miRNAs are involved in cellular adaptation to metabolic stress in GB.70,71 It will be important to validate PBZ-specific
miRNA alterations in order to develop miRNA-based therapies or
new diagnostic applications.
The characteristics of the PBZ are summarized in Table 1 and
Figure 1.
Perspectives on the Glioblastoma Peritumoral
Brain Zone
The Glioblastoma Peritumoral Brain Zone: a Potential
Target for Glioblastoma Therapy?
Among the many promising preclinical studies, only a few have
been successful in human clinical trials. The most recent example is antiangiogenic therapy, which showed no significant effect on overall survival.72 The 2 latest trials on bevacizumab,
Table 1. Summary of the features of the peritumoral brain zone
Approach
Technique
Characteristics of the PBZ
Radiology-MRI
T1
T2 FLAIR
ADC
DTI
†
†
†
†
DCE
†
†
Cell biology
Tumor cells
Reactive astrocytes
Inflammatory cells
GASCs
Molecular
biology
Immunohistochemistry
Genomics
Transcriptomics
†
†
†
†
†
†
†
†
†
†
†
†
†
†
†
†
†
†
†
†
†
†
Proteomics
†
†
No contrast enhancement
Hypersignal
Intensity of the signal correlated to tumor cell infiltration
Inverse correlation between the fractional anisotropy and tumoral infiltration of the
PBZ
Volume transfer coefficient (ktrans) is correlated with tumoral infiltration and
histological grading
Extracellular volume (Ve) and capillary transit time (Tc) are correlated with
molecular markers of hypoxia and overall patient survival
Tumor cells found in the PBZ differ from those in the corresponding tumor mass
Some, but not all tumor clones, migrate away from the tumor core into the PBZ
High proliferation and invasiveness
Different response to drug and radiation challenge in vitro
Migrate along the same route of neural stem cells and share numerous traits with
them
Promote tumor growth and survival by secreting cytokines
May be involved in immune reactions against the tumor
Macrophage density proportional to histological grade and vascular density
Tumor-associated macrophages and their activation state have prognostic value
Phenotype close to CAFs
Angiogenic and tumor-promoting properties in vitro and in vivo, depending on the
GASC subtype
Strong expression of adenosine A1 receptor and STAT1, conferring a neuroprotective
effect
High concentrations of copper and zinc
Expression of CD105, ERKs & JNK, associated with poor prognosis
Expression of VEGF associated with poor progression-free survival
Presence of some but not all genomic alterations in the nearby tumor zone
Loss/partial loss of chromosome 10, polysomy of chromosome 7 and focal
amplification of EGFR
PBZ has a proneural or neural profile, irrespective of the adjacent GB subtype
Interpatient variability, similar to that observed in the corresponding TZ
Intratumoral gradient of gene expression from the tumor core to the PBZ
Overexpression of genes associated with growth and proliferation and cell motility/
adhesion and underexpression of those involved in neurogenesis
Nonneoplastic cells in the PBZ and the GB subtype may influence the molecular
profile of the PBZ
MicroRNA deregulation in GB and adjacent brain
Large interpatient variability complicates the identification of protein markers of the
PBZ
References
27 – 30
34 – 37
23,31
32,33
25,39 – 41
23
25,40
25
38
44 – 46
49
52
53 – 55
15,16
15,16,24
62 – 64
62
59 – 61
32
23
10 – 12
10 – 12
10 – 12
67
68
69
18
Abbreviations: ADC, apparent diffusion coefficient; CAFs, cancer-associated fibroblasts; DCE, dynamic contrast enhancement; DTI, diffusion tensor
imaging; ERKS, extracellular signal-regulated kinases; FLAIR, fluid-attenuated inversion recovery; GASC, glioblastoma-associated stromal cell; GB,
glioblastoma; JNK, c-Jun NH2 terminal kinases; PBZ, peritumoral brain zone.
Neuro-Oncology
1325
Lemée et al.: The peritumoral brain zone in glioblastoma
Fig. 1. Graphical representation of the radiological, cellular and molecular characteristics of the glioblastoma peritumoral brain zone
(GB PBZ). Abbreviations: ADC, apparent diffusion coefficient; CAFs, cancer-associated fibroblasts; DTI, diffusion tensor imaging; GASCs, glioblastomaassociated stromal cells; PBZ, peritumoral brain zone; Tc, capillary transit time; TZ, tumor zone; Ve, extracellular volume.
a humanized monoclonal antibody against VEGF, found that
this treatment increased progression-free survival, but not
overall survival.73,74 Other GB-targeted therapies focus on the
interleukin 13 receptor alpha 2 (IL13Ra2) and EGFR variant III
(EGFRvIII).75,76 These targeted therapies showed promising results in preclinical rodent glioma models but demonstrated limited success in human clinical trials due in part to intratumoral
heterogeneity in the expression of these targets.
It is important to further characterize the cellular and molecular components of the PBZ to identify new targets and to
develop new treatments for GB. Indeed, this region contains
1326
the residual disease from which treatment-resistant recurrent
disease emerges.
Cuddapah et al (2014)38 indicated in a recent review that invading GB cells retain numerous biological traits inherited from
their neural ancestors (eg, Ca2+-AMPA receptors and the Ca2+activated K+ channel KCa3.1) that should be exploited therapeutically to impair the migration of these cells.38,77,78 Ruiz-Ontanon
et al (2013) also found that aVb3 integrin, low levels of cytoplasmic p27, and their downstream effector proteins Rac and RhoA
GTPases are needed for residual tumor cells from the PBZ to acquire an invasive advantage.40 These signaling pathways may
Lemée et al.: The peritumoral brain zone in glioblastoma
Fig. 2. Nano-biotechnological approaches to target the glioblastoma peritumoral brain zone (GB PBZ). Lipid nanocapsules are promising nanoscale
systems for delivering therapeutic molecules to the GB PBZ. They can encapsulate many compounds including drugs, radionuclides, DNA, siRNA,
and nuclease-resistant locked nucleic acids. Their association with antibodies against molecular components overexpressed in the PBZ such as
aVb3 integrin, KCa3.1, CD146, and CSPG4/NG2 can be used to specifically target the tumor cells and/or GASCs present in the PBZ. Their
combination with mesenchymal stem cells, which have endogenous tumor-homing activity and are targeted to the peritumoral region, is
another strategy to improve the delivery of therapeutic agents to the PBZ. Abbreviations: Ca-AMPA, Ca2+ permeable AMPA receptor; CSF-1R,
colony stimulating factor 1 receptor; CSPG4, chondroitin sulfate proteoglycan; GASC, GB-associated stromal cells; GFAP, glial fibrillary acidic
protein; KCa3.1, Ca2+-activated K+ channel.
provide targets for novel anti-invasive therapies for the treatment of GBs. Glycogen synthase kinase-3 (GSK-3) and STAT-3
are other important molecules that modulate GB invasion and
proliferation. Preclinical studies involving the inhibition of these
molecules with specific drugs have shown promising results.79 – 81 The miRNA, miR-625, was recently reported to be
downregulated in the PBZ but not in the tumor.69 The aberrant
downregulation of miR-625 is associated with the local invasion
of gastric cancer cells.82 Therefore, this miRNA may be informative for clinical purposes and for diagnostic and potentially therapeutic applications. We identified 2 subtypes of GASCs in the
surgical margins of GB patients: one subtype with tumor-
Neuro-Oncology
promoting and angiogenic properties and the other without
these pro-oncogenic properties.16 The procarcinogenic GASC
subtype overexpressed several markers including CSPG4/NG2,
nestin, and CD146. These molecules may be prognostic biomarkers of GB and/or targets for GB treatment, as described for other
cancers.83 – 86 Macrophages detected in the PBZ may also be useful targets. Further investigation is needed to determine their
phenotype and function in the PBZ.
Technological approaches should also be developed to target the cellular and molecular components of the PBZ. All attempts to target drugs to the brain are faced with the serious
challenge of crossing the blood-brain-barrier (BBB) that
1327
Lemée et al.: The peritumoral brain zone in glioblastoma
separates the blood from the cerebral parenchyma.87 – 89 Several strategies have been developed to bypass the BBB such as
specific drug formulations able to cross the BBB,6 local disruption of the BBB through focalized ultrasound,90,91 direct intratumoral drug delivery using convection-enhanced delivery
(CED),92,93 and cellular vectors with endogenous tumor-homing
activity such as MSCs.94 To target the delivery of diagnostic and
therapeutic drugs to the PBZ of GB, Chekhonin et al (2012) produced immunoliposomal nanocontainers based on antibodies
against GFAP and the E2 extracellular fragment of connexin
4395 recognizing reactive astrocytes and migrating glioma
cells. Our laboratory has developed and patented a novel nanoscale drug encapsulation system, called lipid nanocapsules
(LNCs).90 These LNCs have the advantage of being prepared
without organic solvent using a low-energy process and are
able to encapsulate various compounds including drugs,96,97
radionuclides,98 DNA,99 siRNA,100 and nuclease-resistant
locked nucleic acids.101 These LNCs, which showed promising
results in glioma models,96 – 98,102 could be used to target the
cellular and molecular components of the GB PBZ through
the grafting of antibodies onto their surface or the use of
MSCs (Figure 2). We recently demonstrated that these cells,
which have endogenous tumor-homing activity and are preferentially found throughout the PBZ, can target the delivery of
LNCs to the tumor.16,94,103 – 105
Glioblastoma Peritumoral Brain Zone: Intraoperative
Assessment for Optimal GB Resection?
Clearly, the quality of the surgical resection is critical for the
overall survival of the patient and the patient’s quality of life
and response to adjuvant therapies.106 – 108 The intraoperative
assessment of the GB PBZ to detect tumor infiltration is extremely important to optimize surgical resection. The PBZ is
typically assessed preoperatively by extemporaneous histopathological examination with a smear test, which provides initial information about the histological nature of the sampled
tissue and the presence of tumor cell infiltration. However,
this examination lacks sensitivity, and the sample is not representative of the entire resection cavity. Thus, new techniques
are required to identify tumor infiltration in the area surrounding the tumor.
Besides examining the PBZ via the preoperative MRI sequences described above, the development of intraoperative
MRI in glioma surgery is also a potentially valuable option for
optimizing the quality of surgical resection. Intraoperative
MRI has shown promising results with a gross total resection
rate of 96% in high-grade glioma, which is substantially higher
than the classical resection rates of 27% –35% reported in the
literature.106,108,109 However, intraoperative MRI has less
influence on patient survival, with one controlled study reporting an average intraoperative survival of 226 days in the intraoperative MRI group vs 154 days in the control group.109
Discussion is ongoing to determine whether intraoperative
MRI is useful for neurosurgery because similar results in
terms of survival can be obtained using alternative techniques
(eg, fluorescence-guided surgery with 5-aminolevulinic acid) at
a much lower cost.110,111 However, fluorescence-guided surgery is unable to remove the entire tumor because isolated
tumor cells may remain outside the fluorescent tumor in the
PBZ.39 Thus, spectroscopic devices capable of detecting and
quantifying fluorescent signals more precisely than the surgeon’s eyes are needed.42,112
A new technique for analyzing the PBZ, optical biopsy, is
emerging in different stages of development (Table 2). These
optical biopsy techniques are divided into 2 categories: in vivo
and ex vivo.
Ex vivo optical biopsies require that brain tissue be sampled
during surgery because of technical limitations. However,
thanks to recent technological advances, in vivo optical biopsies
may hopefully replace ex vivo optical biopsies. Among these
techniques, optic coherence tomography imaging uses interference for precise localization of light deep inside tissue. This
technique enables noncontact assessment of the brain surface
up to 200 mm deep with a spatial resolution of 1 mm, thus allowing discrimination between normal brain, tumor tissue, necrosis, and peripheral infiltrated brain.113,114
Biphotonic microscopy is also currently under evaluation for
analysis of the PBZ. This technique allows fast and label-free
analysis of brain samples, identifies non-centrosymmetrical
structures of the brain (eg, collagen), and provides an overview
of the extracellular matrix architecture with a resolution below
1 mm and a depth of 400 mm.115,116
In vivo optical biopsies allow assessment of tumor infiltration during surgery, thus enabling optimal surgical resection.
One promising in vivo technique is near-infrared confocal endomicroscopy, which can identify isolated tumor cells in the PBZ
during surgery at a precision less than 1 mm and a depth of
250 mm.117,118 This technique, however, is not label-free and
requires intravenous injection of dyes such as indocyanine
green during surgery. Raman spectroscopy is another in vivo
optical biopsy technique based on modification of a laser’s
wavelength to reflect the brain parenchyma at an axial and
depth resolution of 1 mm. This technique has been used in
Table 2. Description of the different techniques available for intraoperative peritumoral brain zone analysis
Technique
Type of
Technique
Spatial
Resolution
Depth of
Penetration
Acquisition
Surface
Time for Image
Acquisition & Processing
Optic coherence tomography
Biphotonic microscopy
Confocal endomicroscopy
Raman spectrometry
Intraoperative MRI
Ex vivo
Ex vivo
In vivo
In vivo
In vivo
1 mm
0.7 mm
1 mm
1 mm
,1 mm
200 mm
400 mm
250 mm
1 mm
Whole brain
Whole brain sample
Whole brain sample
Probe surface
Probe surface
Whole brain
,5 min
5 –45 min
Real time
Real time
15– 20 min
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Lemée et al.: The peritumoral brain zone in glioblastoma
preliminary studies to assess the histological nature of brain
samples and to identify tumor remnants in the surgical resection cavity.119 – 121 Karabeber et al (2014) have used gold-silica
surface-enhanced Raman scattering nanoparticles and a
hand-held Raman scanner to perform image-guided surgical
resection of GBs in a transgenic murine model.122
Conclusion
We have much to learn from the PBZ about the recurrence of
GB. The PBZ contains specific tumor and stromal cells that promote GB growth and invasion. Given the interpatient heterogeneity of GB PBZ, large-scale studies are required to further
characterize this area in order to identify new molecular targets
that could be translated into routine clinical practice. Technical
progress is also needed to assess the presence of tumor infiltration in the PBZ during surgery and thus optimize the quality of
surgical resection. In our opinion, intraoperative MRI is currently the most reliable, easy-to-use technique for analyzing and
delineating brain tumors. This recent progress regarding GB
and its peritumoral characteristics will facilitate development
of personalized targeted therapy and adjuvant treatments of
GB after surgery.
10.
Eder K, Kalman B. Molecular heterogeneity of glioblastoma and
its clinical relevance. Pathol Oncol Res. 2014;20(4):777– 787.
11.
Sottoriva A, Spiteri I, Piccirillo SGM, et al. Intratumor heterogeneity
in human glioblastoma reflects cancer evolutionary dynamics.
Proc Natl Acad Sci USA. 2013;110(10):4009–4014.
12.
Aubry M, de Tayrac M, Saikali S, et al. “From the core to beyond
the margin”: a genomic picture of glioblastoma intratumor
heterogeneity. Oncotarget. 2015;6(14):12094 –12109.
13.
Stieber D, Golebiewska A, Evers L, et al. Glioblastomas are
composed of genetically divergent clones with distinct
tumourigenic potential and variable stem cell-associated
phenotypes. Acta Neuropathol. 2014;127(2):203–219.
14.
Petrecca K, Guiot M-C, Panet-Raymond V, et al. Failure pattern
following complete resection plus radiotherapy and
temozolomide is at the resection margin in patients with
glioblastoma. J Neurooncol. 2013;111(1):19–23.
15.
Clavreul A, Etcheverry A, Chassevent A, et al. Isolation of a new
cell population in the glioblastoma microenvironment. J
Neurooncol. 2012;106(3):493– 504.
16.
Clavreul A, Guette C, Faguer R, et al. Glioblastoma-associated
stromal cells (GASCs) from histologically normal surgical
margins have a myofibroblast phenotype and angiogenic
properties. J Pathol. 2014;233(1):74– 88.
17.
Com E, Clavreul A, Lagarrigue M, et al. Quantitative proteomic
Isotope-Coded Protein Label (ICPL) analysis reveals alteration
of several functional processes in the glioblastoma. J
Proteomics. 2012;75(13):3898– 3913.
18.
Lemée J-M, Com E, Clavreul A, et al. Proteomic analysis of
glioblastomas: what is the best brain control sample? J
Proteomics. 2013;85:165– 173.
19.
De Tayrac M, Etcheverry A, Aubry M, et al. Integrative
genome-wide analysis reveals a robust genomic glioblastoma
signature associated with copy number driving changes in
gene expression. Genes Chromosomes Cancer. 2009;48(1):
55–68.
20.
De Tayrac M, Aubry M, Saı̈kali S, et al. A 4-gene signature
associated with clinical outcome in high-grade gliomas. Clin
Cancer Res. 2011;17(2):317–327.
Funding
The first author, J.-M.L., has received grants from the Société Française
de Neurochirurgie and the Institut National de la Santé et de la Recherche Médicale.
Conflict of interest statement. The authors have no conflict of interest to
disclose.
References
1.
Loiseau H, Huchet A, Rué M, et al. [Epidemiology of primary brain
tumor] [in French]. Rev Neurol (Paris). 2009;165(8 –9):650– 670.
2.
Stupp R, Mason WP, van den Bent MJ, et al. Radiotherapy plus
concomitant and adjuvant temozolomide for glioblastoma. N
Engl J Med. 2005;352(10):987– 996.
21.
De Tayrac M, Saikali S, Aubry M, et al. Prognostic significance of
EDN/RB, HJURP, p60/CAF-1 and PDLI4, four new markers in
high-grade gliomas. PloS One. 2013;8(9):e73332.
3.
Aum DJ, Kim DH, Beaumont TL, et al. Molecular and cellular
heterogeneity: the hallmark of glioblastoma. Neurosurg Focus.
2014;37(6):E11.
22.
Etcheverry A, Aubry M, de Tayrac M, et al. DNA methylation in
glioblastoma: impact on gene expression and clinical outcome.
BMC Genomics. 2010;11:701.
4.
Friedmann-Morvinski D. Glioblastoma heterogeneity and cancer
cell plasticity. Crit Rev Oncog. 2014;19(5):327– 336.
23.
5.
Burger PC, Kleihues P. Cytologic composition of the untreated
glioblastoma with implications for evaluation of needle
biopsies. Cancer. 1989;63(10):2014 –2023.
Lemée J-M, Clavreul A, Aubry M, et al. Characterizing the
peritumoral brain zone in glioblastoma: a multidisciplinary
analysis. J Neurooncol. 2015;122(1):53 –61.
24.
Clavreul A, Etcheverry A, Tétaud C, et al. Identification of two
glioblastoma-associated stromal cell subtypes with different
carcinogenic properties in histologically normal surgical
margins. J Neurooncol. 2015;122(1):1 – 10.
25.
Glas M, Rath BH, Simon M, et al. Residual tumor cells are unique
cellular targets in glioblastoma. Ann Neurol. 2010;68(2):
264–269.
6.
Patel AP, Tirosh I, Trombetta JJ, et al. Single-cell RNA-seq
highlights intratumoral heterogeneity in primary glioblastoma.
Science. 2014;344(6190):1396 –1401.
7.
Scherer HJ. The forms of growth in gliomas and their practical
significance. Brain. 1940;63(1):1–35.
8.
Meyer M, Reimand J, Lan X, et al. Single cell-derived clonal
analysis of human glioblastoma links functional and genomic
heterogeneity. Proc Natl Acad Sci USA. 2015;112(3):851– 856.
26.
Silbergeld DL, Chicoine MR. Isolation and characterization of
human malignant glioma cells from histologically normal
brain. J Neurosurg. 1997;86(3):525– 531.
9.
Soeda A, Hara A, Kunisada T, et al. The evidence of glioblastoma
heterogeneity. Sci Rep. 2015;5:7979.
27.
Nakai K, Nawashiro H, Shima K, et al. An analysis of T2 mapping
on brain tumors. Acta Neurochir Suppl. 2013;118:195– 199.
Neuro-Oncology
1329
Lemée et al.: The peritumoral brain zone in glioblastoma
28.
Pauleit D, Langen K-J, Floeth F, et al. Can the apparent diffusion
coefficient be used as a noninvasive parameter to distinguish
tumor tissue from peritumoral tissue in cerebral gliomas? J
Magn Reson Imaging. 2004;20(5):758 –764.
44.
Lin Q, Balasubramanian K, Fan D, et al. Reactive astrocytes
protect melanoma cells from chemotherapy by sequestering
intracellular calcium through gap junction communication
channels. Neoplasia. 2010;12(9):748 –754.
29.
Min Z, Niu C, Rana N, et al. Differentiation of pure vasogenic
edema and tumor-infiltrated edema in patients with
peritumoral edema by analyzing the relationship of axial and
radial diffusivities on 3.0 T MRI. Clin Neurol Neurosurg. 2013;
115(8):1366–1370.
45.
Fitzgerald DP, Palmieri D, Hua E, et al. Reactive glia are recruited
by highly proliferative brain metastases of breast cancer and
promote tumor cell colonization. Clin Exp Metastasis. 2008;
25(7):799– 810.
46.
30.
Wijnen JP, Idema AJS, Stawicki M, et al. Quantitative short echo
time 1H MRSI of the peripheral edematous region of human brain
tumors in the differentiation between glioblastoma, metastasis,
and meningioma. J Magn Reson Imaging. 2012;36(5):
1072 –1082.
Seike T, Fujita K, Yamakawa Y, et al. Interaction between lung
cancer cells and astrocytes via specific inflammatory cytokines
in the microenvironment of brain metastasis. Clin Exp
Metastasis. 2011;28(1):13– 25.
47.
Rath BH, Fair JM, Jamal M, et al. Astrocytes enhance the invasion
potential of glioblastoma stem-like cells. PloS One. 2013;8(1):
e54752.
48.
Kim J-K, Jin X, Sohn Y-W, et al. Tumoral RANKL activates
astrocytes that promote glioma cell invasion through cytokine
signaling. Cancer Lett. 2014;353(2):194– 200.
49.
Nagashima G, Suzuki R, Asai J, et al. Immunohistochemical
analysis of reactive astrocytes around glioblastoma: an
immunohistochemical study of postmortem glioblastoma
cases. Clin Neurol Neurosurg. 2002;104(2):125–131.
50.
Charles NA, Holland EC, Gilbertson R, et al. The brain tumor
microenvironment. Glia. 2012;60(3):502–514.
51.
Glass R, Synowitz M. CNS macrophages and peripheral
myeloid cells in brain tumours. Acta Neuropathol. 2014;128(3):
347–362.
52.
Deng Z, Yan Y, Zhong D, et al. Quantitative analysis of glioma cell
invasion by diffusion tensor imaging. J Clin Neurosci. 2010;
17(12):1530 –1536.
Nishie A, Ono M, Shono T, et al. Macrophage infiltration and heme
oxygenase-1 expression correlate with angiogenesis in human
gliomas. Clin Cancer Res. 1999;5(5):1107–1113.
53.
Lu S, Ahn D, Johnson G, et al. Diffusion-tensor MR imaging of
intracranial neoplasia and associated peritumoral edema:
introduction of the tumor infiltration index. Radiology. 2004;
232(1):221 –228.
Komohara Y, Ohnishi K, Kuratsu J, et al. Possible involvement of
the M2 anti-inflammatory macrophage phenotype in growth of
human gliomas. J Pathol. 2008;216(1):15 –24.
54.
Engler JR, Robinson AE, Smirnov I, et al. Increased microglia/
macrophage gene expression in a subset of adult and pediatric
astrocytomas. PloS One. 2012;7(8):e43339.
31.
32.
Zhang N, Zhang L, Qiu B, et al. Correlation of volume transfer
coefficient Ktrans with histopathologic grade s of gliomas. J
Magn Reson Imaging. 2012;36(2):355– 363.
Jensen RL, Mumert ML, Gillespie DL, et al. Preoperative dynamic
contrast-enhanced MRI correlates with molecular markers of
hypoxia and vascularity in specific areas of intratumoral
microenvironment and is predictive of patient outcome. Neuro
Oncol. 2014;16(2):280– 291.
33.
Jalali S, Chung C, Foltz W, et al. MRI biomarkers identify the
differential response of glioblastoma multiforme to
anti-angiogenic therapy. Neuro Oncol. 2014;16(6):868–879.
34.
Sundgren PC, Fan X, Weybright P, et al. Differentiation of recurrent
brain tumor versus radiation injury using diffusion tensor
imaging in patients with new contrast-enhancing lesions. Magn
Reson Imaging. 2006;24(9):1131 –1142.
35.
36.
37.
Kinoshita M, Goto T, Okita Y, et al. Diffusion tensor-based tumor
infiltration index cannot discriminate vasogenic edema from
tumor-infiltrated edema. J Neurooncol. 2010;96(3):409–415.
55.
Pyonteck SM, Akkari L, Schuhmacher AJ, et al. CSF-1R inhibition
alters macrophage polarization and blocks glioma progression.
Nat Med. 2013;19(10):1264–1272.
38.
Cuddapah VA, Robel S, Watkins S, et al. A neurocentric
perspective on glioma invasion. Nat Rev Neurosci. 2014;15(7):
455–465.
56.
Bowman RL, Joyce JA. Therapeutic targeting of tumorassociated macrophages and microglia in glioblastoma.
Immunotherapy. 2014;6(6):663 – 666.
39.
Piccirillo SGM, Dietz S, Madhu B, et al. Fluorescence-guided
surgical sampling of glioblastoma identifies phenotypically
distinct tumour-initiating cell populations in the tumour mass
and margin. Br J Cancer. 2012;107(3):462– 468.
57.
Parney IF, Waldron JS, Parsa AT. Flow cytometry and in
vitro analysis of human glioma-associated macrophages.
Laboratory investigation. J Neurosurg. 2009;110(3):572–582.
58.
40.
Ruiz-Ontañon P, Orgaz JL, Aldaz B, et al. Cellular plasticity confers
migratory and invasive advantages to a population of
glioblastoma-initiating cells that infiltrate peritumoral tissue.
Stem Cells. 2013;31(6):1075–1085.
Román-Pérez E, Casbas-Hernández P, Pirone JR, et al. Gene
expression in extratumoral microenvironment predicts clinical
outcome in breast cancer patients. Breast Cancer Res. 2012;
14(2):R51.
59.
41.
Toussaint LG, Nilson AE, Goble JM, et al. Galectin-1, a gene
preferentially expressed at the tumor margin, promotes
glioblastoma cell invasion. Mol Cancer. 2012;11:32.
Mangiola A, Lama G, Giannitelli C, et al. Stem cell marker nestin
and c-Jun NH2-terminal kinases in tumor and peritumor areas of
glioblastoma multiforme: possible prognostic implications. Clin
Cancer Res. 2007;13(23):6970 –6977.
42.
Rampazzo E, Della Puppa A, Frasson C, et al. Phenotypic and
functional characterization of Glioblastoma cancer stem cells
identified through 5-aminolevulinic acid-assisted surgery. J
Neurooncol. 2014;116(3):505– 513.
60.
Sica G, Lama G, Anile C, et al. Assessment of angiogenesis by
CD105 and nestin expression in peritumor tissue of
glioblastoma. Int J Oncol. 2011;38(1):41 –49.
61.
43.
Sofroniew MV, Vinters HV. Astrocytes: biology and pathology.
Acta Neuropathol. 2010;119(1):7 –35.
Lama G, Mangiola A, Anile C, et al. Activated ERK1/2 expression in
glioblastoma multiforme and in peritumor tissue. Int J Oncol.
2007;30(6):1333–1342.
1330
Lemée et al.: The peritumoral brain zone in glioblastoma
62.
Dehnhardt M, Zoriy MV, Khan Z, et al. Element distribution is
altered in a zone surrounding human glioblastoma multiforme.
J Trace Elem Med Biol. 2008;22(1):17– 23.
63.
Haybaeck J, Obrist P, Schindler CU, et al. STAT-1 expression in
human glioblastoma and peritumoral tissue. Anticancer Res.
2007;27(6B):3829–3835.
64.
and stromal endothelial cell compartments. Cancer Res. 2011;
71(16):5374– 5380.
81.
Agudelo-Garcia PA, De Jesus JK, Williams SP, et al. Glioma cell
migration on three-dimensional nanofiber scaffolds is
regulated by substrate topography and abolished by inhibition
of STAT3 signaling. Neoplasia. 2011;13(9):831 –840.
Synowitz M, Glass R, Färber K, et al. A1 adenosine receptors in
microglia control glioblastoma-host interaction. Cancer Res.
2006;66(17):8550– 8557.
82.
Wang M, Li C, Nie H, et al. Down-regulated miR-625 suppresses
invasion and metastasis of gastric cancer by targeting ILK.
FEBS Lett. 2012;586(16):2382– 2388.
65.
Verhaak RGW, Hoadley KA, Purdom E, et al. Integrated genomic
analysis identifies clinically relevant subtypes of glioblastoma
characterized by abnormalities in PDGFRA, IDH1, EGFR, and
NF1. Cancer Cell. 2010;17(1):98 –110.
83.
Svendsen A, Verhoeff JJC, Immervoll H, et al. Expression of the
progenitor marker NG2/CSPG4 predicts poor survival and
resistance to ionising radiation in glioblastoma. Acta
Neuropathol. 2011;122(4):495– 510.
66.
Sturm D, Witt H, Hovestadt V, et al. Hotspot mutations in H3F3A
and IDH1 define distinct epigenetic and biological subgroups of
glioblastoma. Cancer Cell. 2012;22(4):425 –437.
84.
67.
Mangiola A, Saulnier N, De Bonis P, et al. Gene expression profile
of glioblastoma peritumoral tissue: an ex vivo study. PloS One.
2013;8(3):e57145.
Chekenya M, Enger PØ, Thorsen F, et al. The glial precursor
proteoglycan, NG2, is expressed on tumour neovasculature by
vascular pericytes in human malignant brain tumours.
Neuropathol Appl Neurobiol. 2002;28(5):367–380.
85.
Hatanpaa KJ, Hu T, Vemireddy V, et al. High expression of the
stem cell marker nestin is an adverse prognostic factor in WHO
grade II-III astrocytomas and oligoastrocytomas. J Neurooncol.
2014;117(1):183–189.
86.
Akiyama M, Matsuda Y, Ishiwata T, et al. Inhibition of the stem
cell marker nestin reduces tumor growth and invasion of
malignant melanoma. J Invest Dermatol. 2013;133(5):
1384– 1387.
68.
Gill BJ, Pisapia DJ, Malone HR, et al. MRI-localized biopsies reveal
subtype-specific differences in molecular and cellular
composition at the margins of glioblastoma. Proc Natl Acad Sci
USA. 2014;111(34):12550–12555.
69.
Piwecka M, Rolle K, Belter A, et al. Comprehensive analysis of
microRNA expression profile in malignant glioma tissues. Mol
Oncol. 2015;pii:S1574 –7891(15)00056-3.
87.
70.
Godlewski J, Nowicki MO, Bronisz A, et al. MicroRNA-451 regulates
LKB1/AMPK signaling and allows adaptation to metabolic stress
in glioma cells. Mol Cell. 2010;37(5):620–632.
Stockwell J, Abdi N, Lu X, et al. Novel central nervous system drug
delivery systems. Chem Biol Drug Des. 2014;83(5):507 –520.
88.
Godlewski J, Newton HB, Chiocca EA, et al. MicroRNAs and
glioblastoma; the stem cell connection. Cell Death Differ. 2010;
17(2):221 –228.
Tajes M, Ramos-Fernández E, Weng-Jiang X, et al. The
blood-brain barrier: structure, function and therapeutic
approaches to cross it. Mol Membr Biol. 2014;31(5):152– 167.
89.
Bastien JIL, McNeill KA, Fine HA. Molecular characterizations of
glioblastoma, targeted therapy, and clinical results to date.
Cancer. 2015;121(4):502– 516.
Bhowmik A, Khan R, Ghosh MK. Blood brain barrier: a challenge
for effectual therapy of brain tumors. BioMed Res Int. 2015;
2015:320941.
90.
Huynh NT, Passirani C, Saulnier P, et al. Lipid nanocapsules: a new
platform for nanomedicine. Int J Pharm. 2009;379(2):201– 209.
71.
72.
73.
Chinot OL, Wick W, Mason W, et al. Bevacizumab plus
radiotherapy-temozolomide for newly diagnosed glioblastoma.
N Engl J Med. 2014;370(8):709 –722.
91.
Burgess A, Hynynen K. Drug delivery across the blood-brain
barrier using focused ultrasound. Expert Opin Drug Deliv. 2014;
11(5):711 –721.
74.
Gilbert MR, Sulman EP, Mehta MP. Bevacizumab for newly
diagnosed glioblastoma. N Engl J Med. 2014;370(21):
2048– 2049.
92.
Lonser RR, Sarntinoranont M, Morrison PF, et al.
Convection-enhanced delivery to the central nervous system. J
Neurosurg. 2015;122(3):697– 706.
75.
Thaci B, Brown CE, Binello E, et al. Significance of interleukin-13
receptor alpha 2-targeted glioblastoma therapy. Neuro Oncol.
2014;16(10):1304 –1312.
93.
Vogelbaum MA, Aghi MK. Convection-enhanced delivery for the
treatment of glioblastoma. Neuro Oncol. 2015;17(Suppl 2):
ii3 –ii8.
76.
Addeo R, Zappavigna S, Parlato C, et al. Erlotinib: early clinical
development in brain cancer. Expert Opin Investig Drugs. 2014;
23(7):1027 –1037.
94.
77.
Cuddapah VA, Turner KL, Seifert S, et al. Bradykinin-induced
chemotaxis of human gliomas requires the activation of
KCa3.1 and ClC-3. J Neurosci. 2013;33(4):1427– 1440.
Roger M, Clavreul A, Venier-Julienne M-C, et al. The potential of
combinations of drug-loaded nanoparticle systems and adult
stem cells for glioma therapy. Biomaterials. 2011;32(8):
2106– 2116.
95.
Chekhonin VP, Baklaushev VP, Yusubalieva GM, et al. Targeted
delivery of liposomal nanocontainers to the peritumoral zone
of glioma by means of monoclonal antibodies against GFAP
and the extracellular loop of Cx43. Nanomedicine. 2012;8(1):
63– 70.
78.
Ishiuchi S, Tsuzuki K, Yoshida Y, et al. Blockage of
Ca(2+)-permeable AMPA receptors suppresses migration and
induces apoptosis in human glioblastoma cells. Nat Med. 2002;
8(9):971– 978.
96.
79.
Nowicki MO, Dmitrieva N, Stein AM, et al. Lithium inhibits invasion
of glioma cells; possible involvement of glycogen synthase
kinase-3. Neuro Oncol. 2008;10(5):690– 699.
Allard E, Huynh NT, Vessières A, et al. Dose effect activity of
ferrocifen-loaded lipid nanocapsules on a 9L-glioma model. Int
J Pharm. 2009;379(2):317–323.
97.
80.
Williams SP, Nowicki MO, Liu F, et al. Indirubins decrease glioma
invasion by blocking migratory phenotypes in both the tumor
Laine A-L, Huynh NT, Clavreul A, et al. Brain tumour targeting
strategies via coated ferrociphenol lipid nanocapsules. Eur J
Pharm Biopharm. 2012;81(3):690– 693.
Neuro-Oncology
1331
Lemée et al.: The peritumoral brain zone in glioblastoma
98.
Vanpouille-Box C, Lacoeuille F, Belloche C, et al. Tumor
eradication in rat glioma and bypass of immunosuppressive
barriers using internal radiation with (188)Re-lipid
nanocapsules. Biomaterials. 2011;32(28):6781–6790.
99.
David S, Montier T, Carmoy N, et al. Treatment efficacy of DNA
lipid nanocapsules and DNA multimodular systems after
systemic administration in a human glioma model. J Gene
Med. 2012;14(12):769 –775.
100.
Resnier P, David S, Lautram N, et al. EGFR siRNA lipid
nanocapsules efficiently transfect glioma cells in vitro. Int J
Pharm. 2013;454(2):748– 755.
101. Griveau A, Bejaud J, Anthiya S, et al. Silencing of miR-21 by locked
nucleic acid-lipid nanocapsule complexes sensitize human
glioblastoma cells to radiation-induced cell death. Int J Pharm.
2013;454(2):765– 774.
102. Vinchon-Petit S, Jarnet D, Michalak S, et al. Local implantation of
doxorubicin drug eluting beads in rat glioma. Int J Pharm. 2010;
402(1– 2):184– 189.
103.
Roger M, Clavreul A, Venier-Julienne M-C, et al. Mesenchymal
stem cells as cellular vehicles for delivery of nanoparticles to
brain tumors. Biomaterials. 2010;31(32):8393 –8401.
104. Roger M, Clavreul A, Sindji L, et al. In vitro and in vivo interactions
between glioma and marrow-isolated adult multilineage
inducible (MIAMI) cells. Brain Res. 2012;1473:193–203.
105.
Roger M, Clavreul A, Huynh NT, et al. Ferrociphenol lipid
nanocapsule delivery by mesenchymal stromal cells in brain
tumor therapy. Int J Pharm. 2012;423(1):63 –68.
106.
Orringer D, Lau D, Khatri S, et al. Extent of resection in patients
with glioblastoma: limiting factors, perception of resectability,
and effect on survival. J Neurosurg. 2012;117(5):851–859.
107. Chaichana KL, Jusue-Torres I, Navarro-Ramirez R, et al. Establishing
percent resection and residual volume thresholds affecting survival
and recurrence for patients with newly diagnosed intracranial
glioblastoma. Neuro Oncol. 2014;16(1):113–122.
108. McGirt MJ, Chaichana KL, Gathinji M, et al. Independent association
of extent of resection with survival in patients with malignant brain
astrocytoma. J Neurosurg. 2009;110(1):156–162.
111.
Barone DG, Lawrie TA, Hart MG. Image guided surgery for the
resection of brain tumours. Cochrane Database Syst Rev. 2014;
1:CD009685.
112.
Valdés PA, Kim A, Brantsch M, et al. d-aminolevulinic
acid-induced protoporphyrin IX concentration correlates with
histopathologic markers of malignancy in human gliomas: the
need for quantitative fluorescence-guided resection to identify
regions of increasing malignancy. Neuro Oncol. 2011;13(8):
846– 856.
113. Assayag O, Grieve K, Devaux B, et al. Imaging of non-tumorous
and tumorous human brain tissues with full-field optical
coherence tomography. NeuroImage Clin. 2013;2:549 –557.
114.
Chen Y, Aguirre AD, Ruvinskaya L, et al. Optical coherence
tomography (OCT) reveals depth-resolved dynamics during
functional brain activation. J Neurosci Methods. 2009;178(1):
162– 173.
115.
Debarbieux F. [Towards a dynamic anatomopathology of
glioblastoma in mice thanks to in vivo biphotonic microscopy].
Ann Pathol. 2010;30(5 Suppl 1):53–55.
116.
Lemée J, Clavreul A, Rakotoarimalala S, et al. P16.20 analysis
of glioblastoma’s peritumoral brain zone using biphotonic
microscopy. Neuro Oncol. 2014;16(suppl 2):ii82– ii83.
117.
Martirosyan NL, Cavalcanti DD, Eschbacher JM, et al. Use of in
vivo near-infrared laser confocal endomicroscopy with
indocyanine green to detect the boundary of infiltrative tumor.
J Neurosurg. 2011;115(6):1131– 1138.
118.
Böhringer HJ, Lankenau E, Stellmacher F, et al. Imaging of
human brain tumor tissue by near-infrared laser coherence
tomography. Acta Neurochir (Wien). 2009;151(5):507–517.
119. Kalkanis SN, Kast RE, Rosenblum ML, et al. Raman spectroscopy
to distinguish grey matter, necrosis, and glioblastoma
multiforme in frozen tissue sections. J Neurooncol. 2014;
116(3):477 – 485.
120.
Rutka JT, Kim B, Etame A, et al. Nanosurgical resection of
malignant brain tumors: beyond the cutting edge. ACS Nano.
2014;8(10):9716– 9722.
109.
Senft C, Bink A, Franz K, et al. Intraoperative MRI guidance and
extent of resection in glioma surgery: a randomised, controlled
trial. Lancet Oncol. 2011;12(11):997– 1003.
121. Tanahashi K, Natsume A, Ohka F, et al. Assessment of tumor cells
in a mouse model of diffuse infiltrative glioma by Raman
spectroscopy. BioMed Res Int. 2014;2014:860241.
110.
Stummer W, Pichlmeier U, Meinel T, et al. Fluorescence-guided
surgery with 5-aminolevulinic acid for resection of malignant
glioma: a randomised controlled multicentre phase III trial.
Lancet Oncol. 2006;7(5):392 –401.
122.
1332
Karabeber H, Huang R, Iacono P, et al. Guiding brain tumor
resection using surface-enhanced Raman scattering
nanoparticles and a hand-held Raman scanner. ACS Nano.
2014;8(10):9755– 9766.