mRNA Expressions of Specific Gamma-Glutamyl Transferases in Molecular Subtypes of Breast Cancer

Abstract

An increased risk of breast cancer has been reported in individuals with elevated levels of gamma-glutamyl transferase (GGT). GGT1 was the only enzyme used for diagnosis in clinic and human genome contains additional related genes or sequences besides GGT1. From the perspective of amino acid sequences, genes showing substantial similarity (GGT5, GGT6, and GGT7) to GGT1 have been identified. The aim of this study was to investigate the mRNA expressions of GGT1, GGT5, GGT6, and GGT7 in 58 breast cancer patients’ tissue samples by qRT-PCR method. In total, mRNA expressions of GGT5 and GGT7 increased and GGT6 decreased in tumor tissues than those in normal tissues of the same patients (p<0.145, p<0.003 and p<0.05, respectively). Among molecular subtypes, GGT7 expressions were significantly higher in tumor tissues than those in normal tissues of the patients in Luminal A group (p<0.009). Over-expression of GGT7 was observed in almost half of the patients. The research showed mRNA expressions of GGT1, GGT5, GGT6, and GGT7 in breast cancer. Among the four genes, we obtained surprising results for GGT7 and we believe that the activity of this gene should be examined in breast cancer