The effect of glutathione S-transferase gene polymorphisms on susceptibility to uterine myoma

Background: Uterine myomas are benign tumors of the uterus and the most common solid pelvic tumors causing symptoms in approximately 25% of women in their reproductive years. However, its etiology and pathogenesis remain obscure; there is increasing evidence that endometriosis is inherited as a complex genetic trait. Recent studies indicated the involvement of glutathione S-transferase M1 (GSTM1) gene in the pathogenesis of this disease and current investigations are devoted to the other members of phase II detoxification system genes such as glutathione S-transferase T1 (GSTT1). Therefore, current study was carried out to investigate the distribution of GSTM1 and GSTT1polymorphisms in Iranian population in order to estimate possible impact of null-alleles of each gene in development of this disease. Methods: In this study, 50 patients with endometriosis diagnosed by both pathology and laparoscopic findings according to the revised American Fertility Society classification of endometriosis were recruited from subjects referred to the Pasteur Institute of Iran between November 2012 to September 2013. Accordingly, controls (n=50) were subjects without any of aforementioned gynecologic conditions. The genomic DNA was extracted from peripheral blood leucocytes using the salting out method and GSTM1 and GSTT1 genotyping for gene deletions were carried out using Gap-polymerase chain re-action. Logistic regression analysis was applied to assess whether there was any significant risk increase between the case group with higher null genotypes compared to control group. The level of statistical significance was set at 0.05 and all analyses were conducted using the SPSS version 18.0 (SPSS Inc., Chicago, IL). Results: There was significant evidence that the distribution of the GSTM1 and GSTT1 genotypes differed between the patients and the controls with an allelic odds ratio (OR) of 3.56 (95%CI: 1.35-9.37, P=0.01) and 3.92 (95%CI: 1.4-10; P=0.009) respectively. Data analysis also revealed that individuals with both GSTM1 and GSTT1 null genotypes (-/-) had higher risk to develop the disease in comparison to the people with the both present (+/+) genotype (OR:19.23, P=0.007). Conclusion: The findings suggest that the GSTM1 and GSTT1 genetic polymorphisms are associated with the development of endometriosis in Iranian women which is in agreement with previous results obtained in other populations. However, the ethnic variations of polymorphisms should be evaluated in detail and differences should be incorporated into investigations of susceptibility variants for this disease