We were fortunate to be able to demonstrate that the proinflammatory cytokine TNF-α induces transformation of BALB/3T3 cells initiated with 3-methylcholanthrene (MCA) (Komori et al. 1993), which showed that TNF-α is the essential cytokine in tumor promotion since okadaic acid did not show any tumor-promoting activities in TNF-α-deficient (TNF-α−/−) mice initiated with DMBA (Suganuma et al. 1999). The gene discussed is TNF; the disease is neoplasm.