Concentration of these cells in cord blood is strongly positively associated with both cord blood levels of insulin-like growth factor 1 (IGF-1) (Savarese et al, 2007) and birth weight (Strohsnitter et al, 2008), suggesting that IGF-1 may be an important factor in the intrauterine origin of breast cancer. The gene discussed is IGF1; the disease is breast carcinoma.