ICAM3 and plasma cell myeloma: Our results from targeted profiling of ~87,000 cells show BCMA, ICAM3, CD221, and CS1 (SLAMF7) as the most abundantly expressed markers on PCs across all myeloma stages, with BCMA, ICAM3, and CD221 having significantly higher expression levels on overt disease conditions, while also being expressed in precursor states.