Bridging animal and human studies: what are the missing segments in dietary fat and prostate cancer?

Epidemiologic investigations have suggested an association of dietary fat intake with prostate cancer risk, especially risk of advanced prostate cancer. However, supporting evidence from animal studies is limited. Segments that would bridge animal and human studies on dietary fat and prostate cancer--which would determine the future directions of research--are missing. Such segments include 1) well-designed animal studies to evaluate whether dietary fat or fatty acid modulation, particularly by reducing dietary fat and supplementing n-3 fatty acids, reduces the progression of prostate cancer; 2) in vivo identification of intermediate biomarkers that are responsive to dietary fat and fatty acid treatment and may serve as surrogate endpoints in future clinical studies; 3) elucidation of mechanisms by which dietary fat or fatty acid modulation could prevent prostate cancer progression; 4) further epidemiologic studies to estimate dietary exposure more precisely to establish the correlation between dietary fat and risk of prostate cancer; 5) randomized clinical intervention trials evaluating whether dietary fat reduction combined with dietary n-3 fatty acid supplementation delays the recurrence of prostate cancer and improves survival in patients with clinical disease after therapeutic treatment, and whether it prevents or reduces the progression to clinically significant disease in men with latent disease; and 6) studies validating intermediate biomarkers as surrogate endpoints.