Gene polymorphisms in the human progesterone receptor gene (PROGINS) and glutathione S-transferase (GST) and risk of breast cancer: a literature review

Abstract

Breast cancer genetic susceptibility shows two opposite extremes: 1) monogenetic diseases with high penetration, i.e., the inherited mutations in the BRCA1 and BRCA2 genes related to hereditary breast cancers and 2) polymorphisms, which are highly frequent mutations, including 40 to 50% of the population (e.g., polymorphism in the glutathione-S enzyme super-family, glutathione-S transferase (GST) class, present in 50% of Caucasians), with a slightly increased individual risk. Polymorphisms refer to variations in the DNA sequence of genes that code for certain enzymes. Such sequence variations give rise to proteins with variable activity and with different metabolic capacities in population subgroups or single individuals. Based on an extensive review of the Lilacs and Medline databases, where the main studies on this subject were published, the current article aims to provide a comprehensive view of this vast and increasingly important theme. Due to the large number of polymorphisms, the focus was limited to two classes associated with the greatest breast cancer risk: PROGINS and GST. Data in the literature show some disagreement, and national studies are necessary to determine the real prevalence of such polymorphisms in Brazil and to analyze their correlations with breast cancer.