Biomarker recommendation for PD-1/PD-L1 immunotherapy development in pediatric cancer based on digital image analysis of PD-L1 and immune cells.

Anti-PD-1/PD-L1 immunotherapy could offer an alternative to traditional chemo- and/or radiotherapy to treat pediatric cancer patients. To unveil the potential benefit of this new therapeutic approach, the prevalence of PD-L1 and other relevant immune markers using quantitative digital image analysis (DIA) could help to clarify this point. A bridging study was first conducted using commercially available normal formalin-fixed paraffin-embedded (FFPE) tonsils to compare immunostaining patterns and intensities from PD-L1, tumor infiltrating lymphocyte (TIL) markers CD3, CD8, FoxP3, CD45RO, and macrophage marker CD68 in adult (n = 5) and pediatric (n = 10) samples.