BRAF and differentiated thyroid carcinoma: For example, when using the criteria proposed by Turin to define poorly differentiated thyroid carcinoma, which include a solid growth pattern, absence of nuclear features of papillary thyroid carcinoma, and presence of necrosis with a mitotic index of ≥3/10 high-power fields (HPF) or convoluted nuclei, a high frequency of RAS mutations (42-64%) and a low frequency of BRAF V600E mutations (6-9%) are observed 139.