PD-L1 expression was observed in 3 (75%) cases of SCC and 1 (100%) case of adenosquamous carcinoma, but it was absent in cases of adenoid cystic carcinomas and mucoepidermoid carcinomas.
PD-L1 expression was thus compared by immunohistochemistry (IHC) versus RNA in situ hybridization (ISH) in 112 lung cancers by tissue microarray: 51 adenocarcinoma, 42 squamous cell carcinoma, 9 adenosquamous carcinoma, 5 carcinoid, 3 undifferentiated large cell carcinoma, 1 large cell neuroendocrine carcinoma, and 1 small cell carcinoma.