Lack of influence of glutathione S-transferase gene deletions in sporadic breast cancer in Pakistan

Glutathione S-transferases constitute the phase II detoxification enzymes involved in the metabolism and detoxification of a wide range of potential environmental carcinogens. GSTM1 and GSTT1 are polymorphic and their deletions have been found to be associated with breast cancer risk in some of the world populations. The current study was aimed at evaluation of GSTM1 and GSTT1 gene deletions in 150 unrelated breast cancer patients and 150 healthy controls from Pakistani population. Multiplex PCR assay along with CYP1A1 exon 7 as an internal control was used. Our sampled patients and controls had a mean age of 48 (+11.8) and 45 (+7.9) years respectively. The analysis suggested that only 2% breast cancer patient and 8% controls had homozygous GSTM1 gene deletions (OR 0.23, 95% CI 0.06-0.85). A total of 8.7% patients and 18.6% controls had homozygous GSTT1 deletion (OR 0.41, 95% CI 0.25-0.83). The statistical analysis suggest that a non significant number (P>0.05) of individuals compared to controls have GSTM1 and GSTT1 gene deletions. Deletion in both genes was not observed in any of the patients or controls. The present case control study suggests no association of GSTM1 and GSTT1 gene deletions with sporadic form of breast cancer in Pakistani population.