SDC1 and plasma cell myeloma: To profile myeloma B cell lymphopoiesis in our cohorts, we used 13 B cell stage-specific markers (CD10, CD19, CD20, CD22, CD27, CD34, CD38, CD45, CD138, IgA, IgD, IgG, and IgM) in BI and BII panels to profile B lymphoid maturation stages by spanning-tree progression analysis of density-normalized events (SPADE) clustering analysis.