www.genpathdiagnostics.com
G E N A R R AY ™
Molecular
Karyotyping
A leap in cancer diagnosis
we see what others don’t
Molecular Karyotyping: Beyond Conventional Cytogenetics
• Cytogenetic analysis provides valuable diagnostic and prognostic information for the evaluation of hematologic
malignancies. Traditional and new techniques have been applied in clinical oncology with a variable range of
resolution and sensitivity, including chromosome analysis and fluorescence in situ hybridization (FISH).
• However, the resolution of these techniques is still low since the detection of unbalanced rearrangements is
not well defined. In addition, chromosome analysis cannot be performed when the culture fails.
• Recently, the application of DNA array-based technologies such as array comparative genomic hybridization (aCGH)
has enabled the detection of previously undetected copy number changes CNCs and the more precise determination
of genomic break points of regions that are gained or lost with an increased resolution and sensitivity.
GenArray™ is a custom-design microarray
that contains 64,000 DNA oligonucleotide
probes spaced at approximately 50Kb
intervals across the genome. There is a
higher probe density in cancer-relevant
regions, resulting in higher sensitivity and
greater resolution allowing for the
detection of even the smallest genomic
variations with clinical relevance.
Gains or losses greater than 1Mb and
observed in at least 30%–40% of the
patient DNA sample are reported.
Figure 1: A molecular karyotype showing gains and losses across the
genome. Gains are depicted in green and losses in red.
• Array CGH technology does not rely on metaphase chromosomes, and, therefore, the DNA sample can
be obtained from cells in any stage of growth.
• Use of oligonucleotide array allows greater coverage and probes may be present every 21Kb, as opposed to
Bacterial Artificial Chromosome (BAC) arrays, which have a 1Mb–2Mb coverage.
This technology should be used in conjunction with cytogenetic analysis, as it cannot detect balanced
translocations and inversions.
For further information, please contact us at 1 800 627 1479
or visit our website, www.genpathdiagnostics.com.
™
Clinical Indications
Myeloproliferative Neoplasms: In a number of cases, patients with Polycythemia Vera (PV) and Essential
Thromobocythemia (ET) show normal cytogenetics even though array CGH analysis can detect a number
of chromosomal aberrations.
Lymphoproliferative Disorders: Lymphoid malignancies and plasma cell disorders that involve end-stage cells
are difficult to analyze using cytogenetics.
Myelodysplastic Syndrome (MDS): Normal karyotypes in chromosome-banding analysis represent 40%– 45%
of MDS and Acute Myeloid Leukemia (AML) patients.3 GenArray™ currently facilitates the genetic diagnosis of
patients with MDS where chromosome analysis was not successful due to the nature of the disease (culture failures,
low resolution karyotypes or normal results). MDS patients are at high risk of developing AML, and it is important to
screen these patients for any chromosomal abnormalities that cannot be detected by standard cytogenetics.
Array CGH also has proven utility in Chronic Lymphocytic Leukemia (CLL) and other leukemias.
Figure 2: A GenArray™ result showing a 2.9MB deletion on chromosome 4.
References:
1. Rucker F.G., Bullinger L., et al. Disclosure of Candidate Genes in Acute Myeloid Leukemia With Complex Karyotypes
Using Microarray-Based Molecular Characterization J Clin Oncol 2008: 24 (24): 3887– 3894
2. Tefferi A., Sirhan S., et al. Oligonucleotide Array CGH Studies in Myeloproliferative Neoplasms: Comparison With
Conventional Cytogenetic Analysis and JAK2V61-7F Mutational Status Blood 2007: 110 (11)
3. Suela J., Alavarez S., et al. DNA Profiling by Array CGH in Acute Myeloid Leukemia and Myelodysplastic Syndromes.
Cytogenet Genome Res 2007: 118; 304– 309
www.genpathdiagnostics.com
Ordering Information
Test Name
GenArray™ Molecular Karyotyping
Test Code
5306-6
Method
Array CGH
Specimen
Bone Marrow
Turnaround
7 Days
487 Edward H Ross Drive
Elmwood Park, NJ 07407
1 800 627 1479 tel
A business unit of BioReference Laboratories, Inc.
© 2009 BioReference Laboratories, Inc. All rights reserved. 90277–2009/11
1 201 791 8760 fax
www.genpathdiagnostics.com