TP53 and thyroid cancer, nonmedullary, 2: TP53 mutations can be found in ATC either associated with other genetic alterations typical of PTC or FTC, thus suggesting that ATC can derive from the dedifferentiation of well-differentiated longstanding thyroid cancer or as a unique genetic event, thus suggesting a direct role of these mutations in transforming the normal follicular cell into an undifferentiated tumoral cell.