Results from these studies will evaluate the effects of both acute and chronic doses on radiation-induced health risks using a variety of animal models including (1) Alzheimer disease pathology using male APP/PS-1 Alzheimer disease model mice (APPswe/PS-1dE9 transgenic mice) and their wild-type littermates (C57BL/6 background); (2) radiation-induced hepatocellular carcinoma (HCC) in C3H/HeNCrl mice; and (3) radiation-induced lung cancer in male and female wild-type and LA1 mutant (a lung cancer susceptible mouse) mice on a 129 background. The gene discussed is APP; the disease is Alzheimer disease.