The cause of prostate cancer is not known. There is evidence for a genetic predisposition for this disease as evidenced by the increased incidence in families with a history of the illness – some oncogene testing in the karyotype is worthwhile in some patients (e.g. BRCA-2). There are also well recognised racial and geographical differences in the incidence of the disease. For example, there is an almost two-fold higher incidence of prostate cancer amongst black Americans than amongst whites. Interestingly, environmental studies demonstrate a higher incidence of prostate cancer occurring over the generations in migrants from a lower risk area to a higher risk one. Whilst there is some epidemiological evidence for a link between exposure to some pollutants such as heavy metals and chemical fertilisers, any such link is weak and the hypothesised link between incidence and either sexual activity or some venereal diseases (e.g. herpes or cytomegalovirus ) is unfounded.
