In papillary thyroid cancers (PTCS), the new gene fusion involves exons 1–4 from the 5′ end of the TFG fused to the 3′ end of RET tyrosine kinase, leading to a TFG-RET fusion that transforms immortalized human thyroid cells in a kinase-dependent manner (34). Here, RET is linked to thyroid gland papillary carcinoma.