A protein associated with conditions of metabolic imbalance, such as diabetes and obesity, may play a role in the development of aggressive forms of breast cancer, according to new findings by researchers at the National Cancer Institute (NCI), part of the National Institutes of Health, and their colleagues. Metabolic imbalance is often caused by elevated carbohydrate intake, which can lead to over-activating a molecule called C-terminal binding protein (CtBP). This over-activation, in turn, can increase the risk of breast cancer. Results of their work appeared in Nature Communications, Feb. 5, 2013.
"Modifying diet and maintaining a healthy diet, combined with developing pharmacological ways of lessening CtBP activity, may one day lead to a way to break the link between cancer and obesity," said Kevin Gardner, M.D., Ph.D., head of NCI's Transcription Regulation Section, Genetics Branch.
It has been known, primarily through population based studies, that there is a strong link between obesity and cancer. But the mechanism behind this link has been uncertain. A previous study conceived and carried out in Gardner's laboratory found that CtBP repressed expression of a gene associated with breast cancer (BRCA1) at an early age by sensing when the cell was in a high metabolic state that, in turn, led to processing large amounts of carbohydrates in the body.
This early study suggested that obesity and weight gain may contribute to breast cancer by decreasing the level of the BRCA1 tumor suppressor gene expression in response to high carbohydrate intake. This explains, in part, why women who have hereditary mutations of BRCA1 also experience an increased risk of breast cancer if they gain weight.