Can endogenous hyperinsulinaemia explain the increased risk of cancer development and mortality in type 2 diabetes: evidence from mouse models.

There is now convincing evidence of an increased risk of patients with obesity or type 2 diabetes developing cancer. To understand the possible causation, type 2 diabetic muscle lysine to arginine (MKR) mice were studied. Introduction of mammary tumour cell lines resulted in aggressive growth of the mammary tumours in the hyperinsulinaemic MKR female mice. Blocking the insulin receptor activation or reducing the hyperinsulinaemia reduced the mammary tumour burden. Thus, hyperinsulinaemia may be one of the factors in the increased breast cancer risk seen with obesity and type 2 diabetes.