Glutathione S-transferases M1 and T1, and Breast Cancer in the Slovak population

The glutathione S-transferase (GST) genes are involved in the metabolism of various carcinogens. Deletion polymorphisms in the genes GSTM1 (Deletions in GSTM1 occur at a frequency of about 15% in human populations. Individuals who are deletion homozygous, i.e., GSTM1 null, exhibit and absence of enzyme activity. A null allele at the GSTM1 locus is found in 40 %245 % of Caucasians. GSTM1 deficiency may be a risk factor for cancer by providing increased sensitivity to chemical carcinogens. The mechanism of carcinogenicity may be related to an increased formation of DNA adducts in the presence of the null deletion.) and GSTT1(A proportion of the population, varying from 12%–20% in Europeans to 65% in Asians carries a null polymorphism (deletion). Such people do not express the gene and therefore do not have any GSST1 enzyme activity) were investigated in relation to breast cancer risk. The study population consisted of 115 incident breast cancer cases and 132 age-matched controls with no known malignant diseases. GSTM1/T1 genotypes were determined by a multiplex polymerase chain reaction (PCR) method, and odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated by conditional logistic regression model. The relative odds ratio (95 % confidence interval) of breast cancer was 1.227 (0.68–2.22) with the GSTM1 null, 1.08 (0.64–1.81) with the GSTT1 null. The results conclusively show that single gene GST polymorphisms do not confer a substantial risk of breast cancer to its carriers.
This work was supported by grants AV4/0013/05, MVTS Bil/ČR/S/UK/06, 2005/14MFN-06 (Slovak Ministry of Health) and VEGA Fund 1/3379/06.