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. This evidence concerns the gene CXCR4 and medullary thyroid gland carcinoma.