Molecular and clinical follow-up after treatment of multiple myeloma

Multiple myeloma (MM) is a B cell malignancy characterized by accumulation of plasma cells (PCs) in the bone marrow. Traditional methods for the detection of minimal residual disease (MRD) measure the presence of monoclonal immunoglobulin protein secreted by the malignant PCs. However, changes in the level of MRD in MM may span 6 logs, and methods with a high sensitivity and dynamic range are necessary for quantitating MRD in MM. The two main technologies used in MRD detection are flow cytometry and patient-specific reverse transcription (RT) PCR. Patient-specific RT-PCR has high sensitivity and may be beneficial in monitoring patients receiving allogeneic transplantation. However, for the MRD evaluation of autotransplants, where few patients achieve molecular remission, flow cytometry monitoring seems to be sufficient.