SRRM2 and plasma cell neoplasm: As shown in Table S2 and Fig. 7, in all subgroups of plasma cell dyscrasias, the expression of SRRM2 on granulocytes, monocytes, and lymphocytes was low and mostly negative; however, in the subgroup of MM at (SD + PD) stage, we found an increased expression of SRRM2 on granulocytes and monocytes and an increased positive rate, which was still lower than the expression of SRRM2 on plasma cells, and the difference was statistically significant.