The M1 macrophages exhibit a strong antigen presentation ability as they express major histocompatibility complex class II and secrete various proinflammatory cytokines, including interleukin-6, interleukin-12, inducible nitric oxide synthase, reactive oxygen species, and tumor necrosis factor-alpha (TNFα), which have the potential effect of killing cancer cells [38]. This evidence concerns the gene IL6 and cancer.