Association of GSTM1 , GSTT1 , and GSTM3 gene polymorphisms and susceptibility to cervical cancer in a North Indian population

Objective The objective of the study was to evaluate the influence of genetic polymorphisms of GSTM1 , GSTT1 , and GSTM3 on the susceptibility of cervical cancer. Study Design Blood samples from 150 women with biopsy-confirmed cervical cancer and 168 healthy controls were analyzed by multiplex polymerase chain reaction (PCR) to detect the presence or absence of GSTM1 and GSTT1 . Insertion/deletion polymorphism in intron 6 of GSTM3 was determined by PCR. Results The frequencies of homozygous GSTM1 null and GSTT1 null genotypes were found to be significantly higher in cancer patients as compared with healthy controls ( P = .009, odds ratio [OR] 1.52, 95% confidence interval [CI], 1.1 to 2.0 and P = .0004, OR 2.4, 95% CI: 1.4 to 4.0, respectively). The AB genotype of GSTM3 also conferred higher risk of cancer ( P = .053, OR 1.64, 95% CI, 1.0 to 2.6). However, no significant association of at-risk genotypes was observed with any stages of cervical cancer. Interactions among GSTM1 null , GSTT1 null , and AB genotype of GSTM3 resulted in additive predictive risks of cervical cancer. In case-only analysis, carriers of the AA genotype of GSTM3 among tobacco users were at elevated risk of cervical cancer ( P = .024, OR 2.1, 95% CI, 1.0 to 4.1) as compared with AB and BB genotypes. Conclusion GSTM1 null , GSTT1 null , and GSTM3 * AB genotypes may confer higher susceptibility to cervical cancer and cancer risk because at-risk genotypes are additive. Tobacco usage by carriers of GSTM3 * AA has enhanced the risk of cervical cancer as compared with nonusers.