A new process of cancer prevention mediated through inhibition of tumor necrosis factor alpha expression.

Mechanisms of cancer prevention were studied using structurally different cancer-preventive agents, sarcophytol A, canventol, (-)-epigallo-catechin gallate, and tamoxifen, based on our evidence that tumor necrosis factor alpha (TNF-alpha) acts as an endogenous tumor promoter relevant to human carcinogenesis. Pretreatment with the four preventive agents commonly inhibited TNF-alpha mRNA expression and TNF-alpha release in BALB/3T3 cells induced by a tumor promoter, okadaic acid, whereas the expression of early response genes (c-jun, junB, c-fos, and fosB) was enhanced. These results strongly suggest that inhibition of TNF-alpha mRNA expression and its release is a new process of cancer prevention.