Refining precision prognostics in multiple myeloma: loss of miR-221/222 cluster in CD138+ plasma cells results in short-term progression and worse treatment outcome

Abstract

The persistence of high relapse rates and therapy resistance continues to challenge the effective management of multiple myeloma (MM). The identification of novel MM-specific molecular markers could ameliorate risk-stratification tools and accurately identify high-risk patients towards personalized prognosis and therapy. miRNA-seq analysis of CD138+ plasma cells (n = 24) unveiled miR-221-3p and miR-222-3p (miR-221/222 cluster) as the most downregulated miRNAs in R-ISS III compared to R-ISS I/II patients. Subsequently, miR-221/222 levels were quantified by RT-qPCR in CD138+ plasma cells of our screening cohort (n = 141), assessing patients’ mortality and disease progression as clinical endpoints. Internal validation was performed by bootstrap analysis, while clinical benefit was estimated by decision curve analysis. Kryukov et al. (n = 149) and Aass et al. (n = 86) served as institutional-independent validation cohorts. Loss of miR-221/222 cluster was strongly associated with patients’ short-term progression and poor overall survival, which was confirmed by Kryukov et al. and Aass et al. validation cohorts. Intriguingly, miR-221/222-fitted multivariate models offered superior risk-stratification within R-ISS staging and risk-based cytogenetics. Moreover, miR-221/222 loss could effectively discriminate optimal 1st-line treatment responders with inferior treatment outcome. Our study identified the loss of miR-221/222 cluster as a powerful independent predictor of patients’ post-treatment progression, ameliorating prognosis and supporting precision medicine in MM.