BRAF and thyroid cancer, nonmedullary, 2: The HTh7, C643 and HTh83 anaplastic cell lines, the TPC papillary cell line and the FTC133, FTC236, FTC238, ML1 and TT2609 follicular cell lines harbored only wildtype alleles for BRAF. These findings fit well with experimental and pathological evidence indicating an involvement of BRAF mutation in the pathogenesis of about 50% of PTCs and the progression of PTC to ATC, but no occurrence of BRAF mutations in FTC [9,10,12,49].