IL21 and neoplasm: Because the type‐I interferon gene cluster on 9p21.3 is often involved in 9p21 deletions, which also involve MTAP, has been suggested that this deletion may result in reduced expression of a number of genes – for example, CXCL13, CXCL9, XCL2, CD27, and IL21 – by tumor cells and subsequently disable both cell‐intrinsic and cell‐extrinsic tumor suppression, facilitating tumor cells to escape from CD8 T‐cell surveillance [16].