CD274 and carcinoma: By histotype, PD-L1 expression was noted in 50.7% (604/1191) of endometrioid carcinomas, 56% (40/71) of clear cell carcinomas, 73% (102/178) of serous carcinomas, 37% (31/84) of carcinosarcomas, and 72% (21/29) of dedifferentiated carcinomas.