We tested the effect of BRAF inhibition by RNAi and sorafenib in cell lines representing the various genetic profiles found in thyroid tumours in vivo: 8505C harbours a homozygous BRAFV600E mutation, TPC1 harbours a RET/PTC1 rearrangement and wild-type for BRAF, and C643 harbours a RASG13R mutation and wild-type BRAF [21], recently demonstrated to be unique thyroid cancer cell lines origin [22]. This evidence concerns the gene BRAF and thyroid cancer.