Insulin resistance, insulin‐like growth factor I and breast cancer: A hypothesis

Consideration of existing data regarding clinical and biochemical risk factors for the development of breast cancer leads to the hypothesis that enhanced insulin‐like growth factor 1 (IGF‐1) activity plays a significant role in the development of this disease. Abnormal IGF‐1 activity may be related to events occurring prenatally, during puberty, or during adult life. Insulin resistance, a common feature in populations characterized by high caloric intake, may result in the amplification of IGF‐1 action at the tissue level by altering serum concentrations of IGF‐1 binding proteins. Several approaches toward testing the hypothesis are proposed, and potential opportunities for clinical application are described. © 1995 Wiley‐Liss, Inc.