South Indian men more prone to prostate cancers than their counterparts in the north

By Syed Akbar
Hyderabad: South Indian men are relatively more prone to prostate cancers than their counterparts in the north. This is because of their distinct ethnic identity and genetic make-up.
According to a study conducted by the city-based Centre for Cellular and Molecular Biology, the repeat of nucleotides - cytosine, adenine and guanine - on chromosomes has a direct bearing on the onset of prostate cancer in men belonging to certain ethnic communities. The androgen receptor gene possesses polymorphic cytosine, adenine and guanine or CAG tandem repeats and the repeat length has been inversely related to the risk of prostate cancer.
"The distinct ethnic variation in the CAG repeat length may be correlated to differences in prostate cancer risk in different populations, says Dr Thangaraj Kumarasamy of CCMB.
As many as 87 prostate cancer patients and 120 control subjects from South India were studied for the purpose. Prostate cancer, one of the most common malignancies in men, exhibits obscure aetiology. The growth of the prostate gland is dependent on circulating androgens and intracellular steroid signalling pathways. The effects of androgen are mediated through the androgen receptor. Moreover, androgen receptor gene transactivation is important for the normal growth and function of the prostate.
He said studies on CAG repeat variation in prostate cancer risk had been inconsistent. In India the one study conducted on the north Indian population showed significant association. However, there have been no studies on South Indian men to date. Since India is known for its unique population structure, having about 5000 endogamous populations, one would expect CAG repeat length variation among South Indians to be different.
"Therefore, we have attempted to analyse the association of CAG repeat number in the androgen receptor gene of the prostate cancer patients as well as control men from the same ethnic background, and to understand whether repeat length is associated with the age of onset and or cancer progression," he pointed out.