In radiation-induced medullary carcinoma in 4W rats, the expression of Cdkn2a and Cxcr4 increased, whereas that of seven autophagy regulatory genes (Dapk1, Eif2ak3, Gaa, Hgs, Mapkl4, Mapt, and Pim2) and five autophagy machinery components (Atg4b, Atg5, Gabarapl2, Rab24, and Wipi1) decreased. The gene discussed is ATG5; the disease is medullary thyroid gland carcinoma.