Cytokines produced by tumors can attract leukocytes together; in turn, leukocytes generate a series of cytokines, such as interleukin, tumor necrosis factor-alpha, interferon, etc. One of the most persuasive examples of the “relationship between inflammation and cancer” is that individuals with inflammatory bowel disease often later develop colorectal cancer (Herszenyi et al., 2015). The gene discussed is TNF; the disease is inflammatory bowel disease.