In two studies of the effects of HFD initiated at 4 weeks of age in mice overexpressing HER2/Neu in the mammary gland [14,15], HFD promoted tumor development by increasing tumor incidence, but without increasing tumor cell proliferation; there was only a small increase in body weight and no insulin resistance or hyperinsulinemia. The gene discussed is ERBB2; the disease is Hyperinsulinemia.