Dietary fish oil reduces colon cancer risk

It is now well accepted that colon cancer evolves from a multi-step process and is a disease strongly influenced by environmental factors, with diet b eing one of the most important modifying agents. Among dietary factors, the re is cogent evidence indicating a protective effect of fish oil feeding wi th respect to colonic tumor development. We have recently demonstrated that the balance between colonic epithelial cell proliferation and programmed c ell death (apoptosis) can be favorably modulated by feeding fish oil, conta ining n-3 polyunsaturated fatty acids, specifically, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We propose that the suppression of co lonic tumor development by dietary n-3 polyunsaturated fatty acids may be d ue to an effect on the subcellular localization of oncogenic p21 ras. The p otential for fish oil feeding to antagonize ras-dependent signal transducti on is significant because the acquisition of chronically activated ras via mutation or overexpression is a relatively early step in colorectal cancer development.