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October 2, 2012

What role do genes play in prostate cancer?

We are continuing with prostate cancer and what causes it. So far we discussed the effects of diet, exercise and age on prostate cancer. This week we discuss the effects of genes, as manifested by race and family history.{{more}}

Our genes are the blueprints that we come with when we are born. These blueprints exist in our cells and consist of messages from our mother and father. It determines who we are. This blueprint essentially says that whatever your parents are, so are you. Whether they are tall or short, fat or slim, black or white, have sugar or pressure or developed cancer or heart disease will affect you. In other words, its important to know your family history, because it affects you. I meet people who look only at their positive family history. They can tell you that their mother (usually) lived until she was 100 years old, but they will not tell you that their father died at 60 from cancer. These facts are important because what your mother and father died from, or suffer with, will most likely affect you, as it lives in you because it came from them. A lot of people in our society do not know their father and have no desire to. This is dangerous, because this is a situation that what you do not know affects you, so that ignorance is not bliss. What your father and your mother died from affects you.

Prostate cancer is genetic based and this is well established. It is known that men whose father had prostate cancer are four times more likely to suffer from it. Besides, if your father and a brother have prostate cancer, then you are nine times more likely to develop it. This is important, as a lot of men do not know what their father died from and with respect to prostate cancer, I have seen “prostate cancer families”. These are families where most or all of the men develop prostate cancer and usually around age 50. These cancers tend to be aggressive and spread early. So, the men in these families are encouraged to get tested earlier (from 35-40) and often (twice a year) and get biopsied earlier (at PSA 2.5 or if the PSA is rising quickly). This is different from the general guidelines in which men are advised to get tested once yearly at age 40-50 (depending on your race) and to get biopsied at a PSA of 4.0ng/ml. So, to summarize, men who have a family history of prostate cancer should not ignore it. No amount of wishing, positive thinking and ignoring it will cause it to go away! Exercise and diet may reduce the age at which it occurs or may slightly reduce your risk, but make no mistake, be sure your genes will find you out! Many men found out about their family history of prostate cancer only after they developed it at age 55 or 60.

Just as the information on genes and family history is known, so is the information on race and genes. We know that black men are two and a half (21/2) times more likely to develop prostate cancer compared to white men. The contrast is even greater for white Chinese men (four times). Clearly there is a racial component. Even when blacks and white are in the same environment, the relationship of blacks more than whites remain. In addition, blacks in the Caribbean have the highest risk, even above blacks in America and Africa. The only explanation for this racial divide is genetics. That is, blacks and whites have different gene expression for skin colour and this somehow interacts with prostate cancer. It is suggested that the link is testosterone, as black men tend to have generally higher levels of testosterone than whites and Asians. This explains why black men are generally bigger and more muscular than whites. This raised testosterone may also explain why we also have higher rates of prostate cancer, since this cancer is hormone related. This fact also explains why black men are advised to start testing for prostate cancer at age 40 and white men at 50. Next week, we look at the issue of sex and prostate cancer.

For comments or question contact:
Dr. Rohan Deshong
Tel: (784) 456-2785
email: deshong@vincysurf.com