Breast cancer (BC) and cardiometabolic diseases share a multifactorial and modifiable etiology, modulated by complex molecular pathways. Glutathione S-transferase (GST) plays a critical role, providing protection against xenobiotics and regulating levels of enzymes and proteins in the cell. GST variants have a significant impact on susceptibility to diseases whose pathogenesis involves oxidative stress, as is the case in many inflammatory diseases such as BC and cardiometabolic pathologies. However, the expression of these polymorphic variants has not been studied in BC. This study aimed to evaluate the presence of GST mRNA isoforms and their association with clinical and cardiometabolic parameters in women with BC. This was a case-control study, and a total of 57 participants were recruited. Concentrations of glucose and lipids in blood were measured in all the participants. GST variants (GSTT1, GSTM1 and GSTP1 Ile105Val polymorphism) were evaluated in all the participants by real-time PCR analysis. There was a significant association (pGSTP1 and LDL-c in the BC group. However, the control group showed significant associations between blood pressure with GSTT1 and GSTP1 variants with total cholesterol (TC), LDL-c, VLDL-c and triacylglycerols (TG). Therefore, GSTT1 and GSTP1 variants could be emerging biomarkers to discriminate between BC cases related or not to cardiometabolic disease factors. View Full-Text ►▼ Show Figures This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited