CD274 and breast carcinoma: The human breast cancer cell line MDA-MB-231, fibrosarcoma cell line HT1080, glioblastoma cell line U87MG and immortalized mesenchymal cell line SCP-1 were positive for PD-L1 expression, while the prostate cancer cell line PC-3, which had already been stably transduced to express human PSCA, was PD-L1 negative.