In our research population, all the plasma cells in the donor BM samples showed the expected CD45-/CD138+/CD19dim+/CD56-/Ki-67− phenotype, while the MM patients BM demonstrated mixed characteristics, including both κ and λ clonality, abhorrent CD56, CD19 and CD117 expression and a variation in the presence of proliferating plasma cells (>20% Ki-67 positivity) (Table 2) [28–31]. This evidence concerns the gene KIT and Miyoshi myopathy.