Previous studies have shown that mucositis is not only a manifestation of tissue change, but also with systemic effects, with elevation of proinflammatory cytokines in serum, such as TNF-α, IL-1β, and IL-6 of 5-FU-treated patients, in association with the chemotherapy toxicity without any improvements in its anti-tumor activity [39]. The gene discussed is IL6; the disease is neoplasm.