We previously described discordance between gene expression and protein measurement for CRBN in MM cell lines.25 Thus, we next analyzed the expression of Ikaros, Aiolos, c-Myc and IRF4 using analytically validated semi-quantitative immunohistochemical assays in primary bone marrow samples of normal (n=10) versus malignant (n=24) plasma cells by co-staining for CD138 and either Ikaros, Aiolos, c-Myc or IRF4, respectively (Figure 1b). The gene discussed is CRBN; the disease is Miyoshi myopathy.