BRAF and differentiated thyroid carcinoma: The molecular evidence comes from a histological study analyzing genetic variations of papillary thyroid carcinomas in a United States institution from 1974 to 2009, which showed sharply rising percentages of the follicular variant histology (from 18% to 44%) and RAS mutations (from 3% to 25%), overall stable prevalence of BRAF mutations but increased percentage within the classic papillary type (from 50% to 77%), and a decreased proportion of RET/PTC rearrangements (11% to 2%) [28].