RET and differentiated thyroid carcinoma: The molecular pathogenesis of papillary thyroid carcinomas (PTC) is largely associated with genetic alterations in the RET-RAS-RAF-MAPK pathway usually caused by RET/PTC rearrangements (13%–43%) or activating point mutations in the BRAF (29%–83%) or RAS-family genes (0 %–21 %).