PD-L1 testing using the clone 22C3 pharmDx kit for selection of patients with non–small cell lung cancer to receive immune checkpoint inhibitor therapy: are cytology cell blocks a viable option?

摘要

IntroductionProgrammed death ligand 1 (PD-L1) testing of non-small cell lung cancer (NSCLC) specimens helps select patients most likely to respond to immune checkpoint inhibitors. PD-L1 immunohistochemical testing is approved for formalin-fixed, paraffin-embedded (FFPE) surgical pathology specimens; however, the testing performance on FFPE cytology cell block specimens is unknown.