The link appears to be vitamin D specific at least for colorectal cancer as shown by PMID  I have seen some papers discussing the theory behind the link but I havent really looked into it in much detail Maybe someone else can comment on this  But if large epidemilogical studies are showing that vitamin Dsunlight is a factor in reducing cancer risk is this not enough to at least mention it Do we know the exact biological mechanism behind the other cancer risks My contribution which was removed by jfdwolff was just a short paragraph summary taken from a recent review and I think it is appropriate to put it back in