Correlation of GSTP1 Polymorphism with Severity of Prostate Cancer in an Eastern Indian Population

Abstract

Background: GSTP1 is one of the Glutathione-S-Transferases (GSTs) which suppress tumor genesis by detoxifying toxic carcinogens and reactive oxygen species (ROS). Prostate cancer is related to several mutations affecting the expression of GSTP1. A single nucleotide polymorphism (SNP: Ile105Val) in the GSTP1 gene results insignificant reduction in its anticancer activity. The current case control study was conducted to ascertain the risk of association of GSTP1polymorphism with risk of cancer prostate in an Eastern Indian population. Materials and Methods: During a study period of 2 years, DNA was isolated using the phenol chloroform extraction method from the blood of 225 histopathologically diagnosed prostate cancer patients and 120 matched controls. The GSTP1 polymorphism was assessed by PCR amplification of the gene followed by restriction digestion with Alw261 (a restriction enzyme derived from Acinetobactro lwoffi RFL26). Histopathological grading in the case group was performed using Gleason’s scores and International Society of Urological Pathology (ISUP) grading. Results: Comparison of the distribution of different GSTP1 alleles between the case and control groups was performed by chi square test and odds ratio analysis. A χ2 value of 18.56 suggested significantly higher number of G alleles in the case group. An odds ratio of 2.25 with a confidence interval of 1.52 to 3.34 for 95% CI showed that the G allele in GSTP1 gene were linked with greater risk of prostate cancer. Post hoc ANOVA and logistic regression suggested that cases having G alleles had more progressive form of diseases as evident from ISUP grades. Conclusion: From our study we can conclude that GSTP1 polymorphism is not only significantly associated with risk of prostate cancer but also with its severity in our Eastern Indian population. GSTP1 polymorphism should be considered as a prognostic indicator for prostate cancer patients along with planning for more aggressive management of the disease.