In addition to its direct effect on cell killing, radiation at optimal doses can cause release of proinflammatory cytokines such as IL-1β and TNFα [85,86], increase FAS expression on tumor cells rendering them susceptible to FAS-ligand-expressing lymphocytes [87], and increase MHC-I expression on tumor cells making them more readily detected by CD8+ T cells [88]. This evidence concerns the gene CD8A and neoplasm.