NCAM1 and POEMS syndrome: In this study, the immunophenotype of the detected monoclonal PCs in POEMS syndrome using POEMS-flow was CD19−/CD56+ in 5/18 (27.8%), CD19−/CD56− in 12/18 (66.7%), and CD19+/CD56− in 1/18 (5.6%) cases, respectively (Fig. 2B).