ATR and colorectal carcinoma: Another recent study identified that irradiated colorectal cancer (CRC) cells use the ataxia-telangiectasia and Rad3-related (ATR)-mediated DNA double-strand break repair pathway to upregulate CD47 and PD-L1, which interact with SIRPα and PD-1, respectively, to suppress phagocytosis and tumor-associated antigens (TAA) cross-presentation by APCs (24).