CD274 and cancer: Copy number amplifications of 9p24.1 have been associated with increased PD-L1 expression in several cancers, and occur most commonly in mediastinal large B-cell lymphoma, classical Hodgkin’s lymphoma [56] and triple-negative breast cancer [57], but have also been described in ovarian, head and neck, bladder, cervical cancers, sarcomas and colorectal cancers, albeit at lower frequencies [8,58].