CD274 and neoplasm: PD-L1 (also known as CD274) was only marginally overexpressed (p = 0.02) in BCC compared to healthy skin tissue in the low-As-exposure setting, suggesting potential beneficial effect, but PD-L1 was not overexpressed in tumor tissue in the high-As-exposure group (p = 0.83) possibly suggesting lack of response to PDL1 inhibitors in such cases.