Null polymorphism of GSTM1 gene in susceptibility of breast cancer

evidence based on meta-analysis

Abstract

Introduction: Breast cancer is the second most common cancer worldwide and the first more common in females. Epidemiological data show the effect of carcinogens and environmental factors in the increased susceptibility of developing breast cancer. In the context of molecular assessments, the null polymorphism of GSTM1 gene is commonly studied in an attempt to associate with the development of this neoplasm. Objective: To evaluate whether individuals with the GSTM1-null polymorphism possess susceptibility to breast cancer. Methods: It was conducted a meta-analysis of 10 case-control studies, which had patients with histological confirmed breast cancer and used PCR and/or DNA sequencing to determine the null polymorphism of GSTM1 gene. The analysis was performed after gathering the necessary data (author, publication year, country and results). Statistical calculations and the representation of the data were obtained with the help of BioEstat® 5.0 software. Results: The total number of individuals, after grouping the data was 7,607 (3,759 cases and 3,848 controls). The frequencies for the null polymorphism of GSTM1 gene were, respectively, 51.0% in the case group and 50.3% in the control group. The analysis of the obtained data revealed OR: 0.967 and 95%CI 0.883–1.060. Conclusion: According to the data obtained by meta-analysis it was not found significant association between GSTM1-null polymorphism and the development of breast cancer. Thus, the results of this study revealed that the polymorphism in question did not change the susceptibility to breast cancer, so it should be considered other factors with greater significance, such as smoking, other genetic markers like BRCA1 and BRCA2, parity, among others.