Longer (TA)n Repeat but Not A49T and V89L Polymorphisms in SRD5A2 Gene May Confer Prostate Cancer Risk in South Indian Men

Testosterone is converted to 5 alpha-dihydrotestosterone (DHT) by 5 alpha-reductase enzyme, which is encoded by the SRD5A2 gene. DHT is the main androgen responsible for prostate growth. We have analyzed the complete coding region of the SRD5A2 gene in 87 histologically confirmed prostate cancer (PC) patients, 40 benign prostatic hyperplasia (BPH) cases, and 96 control samples from southern parts of India. The study revealed the A49T site to be monomorphic, the V89L site to be highly polymorphic, and the (TA)(n) repeat site to be polymorphic with only 2 alleles in our populations. The distribution of V89L alleles between PC cases and controls was not significantly different; however, (TA)(9) alleles distributed differently between the 2 groups. BPH cases exhibited alleles similar to controls at all polymorphic sites. The sequencing of the whole coding region did not reveal any other known or novel polymorphism in this gene. Our study emphasizes that the (TA)(9) allele might confer certain PC risk but that A49T and V89L polymorphisms do not confer PC risk in South Indian men.