Dietary fat, fatty acids and prostate cancer.

International comparisons suggest a relationship between prostate cancer incidence and dietary fat, an inference supported by migration studies, the changing incidence rates and levels of animal fat consumption in Japan and the results from some case-control studies. Overall, however, epidemiological studies have been inconclusive, and although prostate cancer is one of the hormone-dependent tumors, evidence of interactions between dietary fats and male endocrine function is incomplete. Laboratory experimentation has shown that n-6 fatty acids stimulate and n-3 fatty acids inhibit human prostate cancer cells in culture; also, feeding diets rich in marine oils suppresses growth of these cells as solid tumors in athymic nude mice. These growth effects of polyunsaturated fatty acids appear to involve both prostaglandins and leukotrienes and to interconnect with autocrine regulation by epidermal growth factor-related polypeptides.