Among thyroid cancers, PTC is associated with marked over-expression (up to 100 folds) of the c-met proto-oncogene, which, instead, is rarely expressed in other thyroid tumors, including FTC, ATC and MTC (Di Renzo et al. 1995; Oyama et al. 1998; Trovato et al. 1998). The gene discussed is MET; the disease is thyroid cancer, nonmedullary, 2.