Frequency of Genetic Polymorphism in Gstm1, Gstt1 and Gstp1 Genes Associated With Breast Cancer in Women: A Review

Abstract

Genetic polymorphisms in genes related to the metabolism of xenobiotics, how the genes of the glutathione S-transferases superfamily (GSTM1, GSTT1 and GSTP1) have been associated with an increased risk for breast cancer (BC). A literature review was performed using the database PubMed, verifying the frequency of GSTM1, GSTT1 and GSTP1 polymorphisms in studies associated with breast cancer in the last decade, including 27 studies, 14 verified the frequency of GSTM1 and GSTT1 null polymorphisms in women without cancer and 22 in women with cancer; and for the GSTP1 gene, 12 studies verified the genotypic frequency of GSTP1 A/G in women without breast cancer and 18 in women with breast cancer. The mean frequency of the GSTT1 and GSTM1 null genes found in studies with women without breast cancer was 28% and 45% and the mean allele frequencies of the GSTP1 gene for women without breast cancer was 57.7% for the Ile allele and 34% for the Val allele, and the mean frequency of the GSTT1 and GSTM1 null genes found in studies with women with breast cancer was 34.7% and 41.4% and the mean allele frequencies of the GSTP1 gene for women with breast cancer was 59.8% for the Ile allele and 40.2% for the Val allele. Therefore, considering the importance of these genes in carcinogen metabolism, together with the allelic and genotypic frequencies of the polymorphisms studied in this review that differ from one study to another, we suggest that other factors may influence this distribution.