NordicQC 2017 Abstract
Enabling PD-L1 IHC standardisation using defined reference standards and digital pathology
Delphine Cougot, Farah Patell-Socha, Philippe Colin, Colin Barker, Paul Morrill and Karin Schmitt
There is growing concern regarding intra‐ and inter‐laboratory reproducibility of
Immunohistochemistry (IHC) assays performed with Formalin‐Fixed Paraffin Embedded (FFPE) tissue
sections. The subjective interpretation and scoring of positive immunostaining presents significant
challenges to even established biomarker targets. For new targets such as Program cell Death Ligand1 (PD-L1) this need is becoming crucial, especially given the breadth of potential variables, including
the range of companion diagnostic assays (including those in development). There is a growing need
to have defined, consistent and sustainable reference materials to support reproducibility and
methodology transfer. Using CRISPR gene editing technology, we have developed precisely defined
PD-L1, IHC HDx™ Reference Standards with a range of controlled protein expression to understand
the differences in assay performance, establish the practical lower limit of detection, support
laboratories with tools to routinely monitor and standardize workflows, from instrumentation to assay
to antibody. Cell lines are extensively characterised by molecular and protein assays. In addition, we
use quantitative digital pathology to further define positive and negative core for each biomarker,
providing the tools to validate the laboratory workflow. Differences in the four PD-L1 IHC assay will
evaluated and discussed.