Glutathione S-transferase T1 polymorphism is associated with breast cancer susceptibility.

The association between present/null polymorphism of glutathione S-transferase T1 (GSTT1) and breast cancer risk are still inconclusive. We performed a meta-analysis to derive a more precise estimation of the relationship. A total of 48 studies including 17,254 cases and 21,163 controls were involved in this meta-analysis. When all studies were pooled into the meta-analysis, significantly elevated breast cancer risk was associated with null genotype (OR=1.138, 95% CI=1.051-1.232). When stratified by ethnicity, significantly increased risks were found for Caucasians (OR=1.185, 95% CI=1.075-1.306), but no statistically significantly increased risks were found in Asians (OR=1.017, 95% CI=0.846-1.223) and Africans (OR=1.160, 95% CI=0.815-1.650). In the subgroup analysis by controls source, statistically significantly elevated risks were both found in population-based studies (OR=1.123, 95% CI=1.014-1.243) and hospital-based studies (OR=1.181, 95% CI=1.056-1.321). When stratified by menopausal status, no statistically significantly increased risks were found in premenopausal women (OR=1.115, 95% CI=0.925-1.345) and postmenopausal women (OR=1.077, 95% CI=0.992-1.169). In summary, this meta-analysis suggests that the GSTT1 null genotype is a risk allele for breast cancer development. However, large sample and representative population-based studies with homogeneous breast cancer patients and well matched controls are warranted to confirm this finding.