Plasma cell maturity as a predictor of prognosis in multiple myeloma

In this study, the impact of plasma cell maturity on the prognoses of multiple myeloma (MM) patients in the era of novel agents was investigated. Myeloma cell maturity was classified via immunophenotyping: myeloma cells showing mature plasma cell 1 (MPC-1)-positive and CD49e-positive cells were considered mature type; MPC-1-positive and CD49e-negative cells were considered intermediate type; and MPC-1-negative cells were considered immature type. This study included 87 newly diagnosed MM patients who were initially treated with bortezomib and/or chemotherapy. Myeloma cell maturity was a critical factor affecting overall survival (OS) in the cohort, with median OS not reached in mature-type, 50 months in intermediate-type, and 20 months in immature-type cells. Multivariate analysis showed that immature type and stage III according to the International Staging System were both independent prognostic factors affecting OS. The findings of this study demonstrate the clinical importance of myeloma cell classification according to immunophenotyping using MPC-1 and CD49e antibodies to determine patient prognosis in this era of novel therapeutic agents.