Indeed, the analysis highlighted miR-221/222 loss in CD138+ plasma cells as a potent predictor of worse survival (HR: 2.720; 95% CI: 1.464–5.052; p = 0.003; Fig. 3F, Supplementary Table 2) and higher risk for post-treatment progression (HR: 1.718; 95% CI: 1.057–2.794; p = 0.029; Fig. 4C, Supplementary Table 2) of MM patients, independently of R-ISS stage, high-risk cytogenetics [t(4;14), t(14;16), del(17p13), gain/amp(1q21)], B2M, LDH, creatinine levels, HDM/ASCT, patients’ gender and age. This evidence concerns the gene SDC1 and Miyoshi myopathy.