In NK cells derived from the CRC tissue, genes associated with cytotoxic features such as FCGR3A (also known as CD16) and PRF1 (encoding perforin) decreased, and inhibitory markers such as TIGIT, FAS, and PDCD1 (also known as PD-1) increased (Figure 4A). The gene discussed is PRF1; the disease is colorectal carcinoma.