Evaluating polymorphic status of glutathione-S-transferase genes in blood and tissue samples of prostate cancer patients.

Prostate cancer is the most common urologic malignancy, involving multiple factors. There is evidence that suggests that detoxification enzymes and growth factors may play a role in its development . The glutathione S-transferase (GST) enzymes detoxify several carcinogens and genetic polymorphisms in GSTM1, T1, and P1 (Ile105Val) have been reported to be associated with prostate cancer, mainly from blood samples. As expression studies suggest differential expression of different genes in tissues, we hypothesize that polymorphic status may be differently expressed for GSTM1, GSTT1 and GSTP1 gene in blood and tissues of prostate cancer patients and BPH controls, impacting on the development of prostate cancer. To study this, we extracted DNA from blood and tissue samples of patients undergoing biopsy procedures or transurethral resection of prostate tissue. Genotyping for GSTM1 and T1 was conducted by multiplex PCR and for GSTP1 by the PCR-RFLP method. Our results suggested no significant differences in frequency distribution of M1, T1 and P1 between blood and tissue samples of patients and controls, but in a few patients differences in polymorphic status were observed. However, they were not significant. Furthermore, we observed a significant risk of prostate cancer with null allele of GSTT1 and GSTM1 and Val allele of GSTP1, supporting our previous findings. A study with large sample size using radical prostectomy tissue now needs to be performed to attain a specific conclusion.