In our study, most PC subsets overexpressed CD200 (related to a poor PFS in PC1) and CD28 (related to a worse OS in PC3) in both premalignant MGUS/SMM and active MM, while fewer PC subsets showed an increase in CD117 (both premalignant and active MM stages) and CD56 (active MM) expression. This evidence concerns the gene KIT and Miyoshi myopathy.