Causes of Prostate Cancer
No one knows what causes prostate cancer to develop. It becomes more common with age, is more common in some ethnic groups, such as African Americans, and is more likely to develop in men who have immediate relatives (father or brother) who have had it. In about 1 out of 10 cases, an inherited abnormal gene appears to be involved. It is also more common in some countries, such as the U.S., than others, such as Japan. But when men from other countries in which the incidence is low, such as Japan, move to the U.S., the rate of developing prostate cancer increases in their sons and grandsons. All this suggests that there is an interaction between genetics and environmental causes. Differences in diet have been suggested to be the primary environmental factor. But, on the other hand, there may be more prostate cancer in this country simply because it is detected more.
It is thought that potential causal factors act by altering the balance of male hormones in the body because prostate cancer is a hormone-sensitive cancer, like breast cancer. The male sex hormone, testosterone, produced by the testes influences the growth and spread of prostate cancer. Thus, higher testosterone levels or greater lifetime exposure to testosterone appears to contribute to its development. This has been used to explain the higher incidence rates in African Americans, who tend to have higher average testosterone levels than other ethnic groups or in tall men who may have had an earlier onset of higher testosterone levels.
