TP53 and poorly differentiated thyroid gland carcinoma: It has also been shown [4] that ATC or poorly differentiated thyroid carcinoma (PDTC) arises from the evolution of well-differentiated thyroid tumors, primarily through the gradual accumulation of additional genetic abnormalities, that the most typical genetic alteration leading to the development of this phenomenon is the loss of TP53 tumor suppressor, and that TP53 mutations also affect the efficacy of chemotherapy and radioiodine therapy [5].