Utility of Flow Cytometry to Classify Abnormal Plasma Cell Populations in Marrow Samples Collected from Patients with Putative Plasma Cell Neoplasms

Plasma cell neoplasms comprise a spectrum of diseases that include monoclonal gammopathy of undetermined signi-ficance (MGUS) and multiple myeloma (MM). Flow cytometric immunophenotyping has become an invaluable tool as an ancillary and diagnostic test for hematologic malignancies and is being used with increasing frequency in the diag-nosis and monitoring of plasma cell neoplasms. As multiparameter flow cytometry has evolved, faster fluidics and detection systems facilitate the screening of a large number of events and the detection of multiple antigens simultaneously. This review addresses the approaches used to evaluate clonal plasma cell neoplasms and describes different surface and cytoplasmic markers and techniques that are important for the study of these diseases.