IL-1α, a proinflammatory cytokine, plays a divergent role in tumorigenesis; pro- as well as anti-tumor effects are described: while IL-1α may support cell cycle arrest, T-cell activation, and tumor regression in some studies, tumor-promoting effects in other studies include induction of proliferation, angiogenesis, and lymph angiogenesis. This evidence concerns the gene IL1A and neoplasm.