gamma-glutamyl transferase and risk of breast cancer

摘要

gamma-glutamyl transferase (GGT), which is found in both serum and cell plasma membrane, has an important antioxidant effect through the metabolism of gluta-thione. Conversely, pro-oxidant species, including superoxide and hydrogen peroxide, are produced during glutathione catabolism as a result of interaction with trace levels of cellular iron ions. Because of its protective role in oxidative stress, serum GGT has been found to be elevated in many pathological processes, including liver disease, cardiovascular disease, renal disease, diabetes, kidney disease and cancer. There is also mounting evidence to suggest that elevated GGT may be associated with an increase in risk of breast cancer. In a population-based cohort of over 90,000 Austrian women, serial serum GGT levels were measured and the participants were followed for a median of 13.5 years. During this time, 4884 cancers were diagnosed. When women with low normal GGT levels (<18 U/l) were compared with all higher categories, there was a highly significant elevation of cancer risk (p < 0.0001).