Glutathione S-transferase M1, M3, P1, and T1 genetic polymorphisms and susceptibility to breast cancer

This study was undertaken to examine if glutathione S-transferase (GST) MI, M3, P1, and T1 genotypes affected breast cancer risk in Finnish women. The study population consisted of 483 incident breast cancer cases and 482 hea lthy population controls. Genotyping analyses were performed by PCR-based m ethods, and odds ratios (ORs) and 95% confidence intervals (CIs) were calcu lated by unconditional logistic regression adjusting for known or suspected risk factors for breast cancer. When the genes were studied separately, th e only significant finding was between GSTM1 null genotype and postmenopaus al breast cancer risk (OR, 1.49; 95% CI, 1.03-2,15), Conversely, when the p otential combined effects of the at-risk genotypes were examined, significa nt associations were observed only among premenopausal women. Although only a moderate risk of breast cancer was seen for premenopausal women concurre ntly carrying the GSTM3*B allele containing genotypes and the GSTP1 Ile/Ile genotype (OR, 2.07; 95% CI, 1,02-4,18), the risk rose steeply if they simu ltaneously lacked the GSTT1 gene (OR, 9,93, 95% CI, 1,10-90,0), A borderlin e significant increase in the risk of breast cancer was also seen for preme nopausal women with the combination of GSTM1 null, GSTP1 Ile/Ile, and GSTT1 null genotypes (OR, 3.96; 95% CI, 0,99-15,8), Our findings support the vie w that GST genotypes contribute to the individual breast cancer risk, espec ially in certain combinations.