Immunoglobulin gene IGKV1-33 is specifically expressed in P23 multiple myeloma patients (Figure 1, P = 5.3E-30, one-way analysis of variance), while IGHV4-28 is specifically expressed in P21 multiple myeloma patients (Figure 1, P = 1.8E-12, one-way analysis of variance). Here, IGHV4-28 is linked to plasma cell myeloma.