A high percentage of BRAF(V600E) alleles defines a PTC molecular subtype and predicts a poorer disease outcome. The analysis of BRAF mutations by pyrosequencing is useful to refine the risk stratification of patients with PTC.

These data demonstrate that clonal BRAF(V600E) is a rare occurrence in PTC, although frequently this cancer consists of a mixture of tumor cells with wild-type and mutant BRAF. These results suggest that BRAF mutation in PTC is a later subclonal event, its intratumoral heterogeneity may hamper the efficacy of targeted pharmacotherapy, and its association with a more aggressive disease should be reevaluated.