FGFR3(K650E), a mutant found in multiple myelomas and skeletal dysplasia patients, is localized on the Golgi, then autophosphorylated,51, 52 and PDGFRα(mut) and Kit(mut) expressed in HEK293 or NIH3T3 localize to the Golgi region.29, 35, 53 H-Ras and SFKs, which are downstream molecules of RTKs, can initiate mitogenic signaling from the Golgi apparatus.49, 50, 54, 55 However, there has been no direct evidence that the mutant receptors cause oncogenic signaling on the Golgi apparatus. This evidence concerns the gene PDGFRA and plasma cell myeloma.