CD274 and breast cancer: To determine whether the P2Et-mediated modulation of PD-L1 could be generalized or is specific to these cell lines, we assessed PD-L1 expression on the murine melanoma cell line (Mel-Rel), the murine breast cancer cell line (TS/A), the human melanoma (LAU 145 and Me 290), and the human breast (MCF-7 and MDA-MB-468) cancer cell lines.