NRAS and Miyoshi myopathy: Moreover, concerning the mutational status of genes recognized in the mitogen-activated protein kinase (MAPK) signaling, such as BRAF, NRAS, and KRAS, more recently, Lionetti et al. [22] have demonstrated, in a large panel of 167 patients representative of the different forms of PC dyscrasias (132 MM, 24 pPCL, and 11 sPCL), that mutations were found in 12% (BRAF), 23.9% (NRAS), and 29.3% (KRAS) of cases, respectively.