Figure 1: RET protein domains. Schematic view of the RET oncoprotein showing conserved domains of signal peptide (SP), cadherin repeat domains (CAD), cysteine rich region (CYS), transmembrane domain (TM), and protein tyrosine kinase (Kinase) where reported variants associate to three specific disease phenotypes; familial medullary thyroid cancer (FMTC), multiple endocrine neoplasia type 2A (MEN2A) and multiple endocrine neoplasia type 2B (MEN2B).