The ability of a new Gal-3 antagonist, GCS-100, to induce myeloma cell death by modulating MCL1 apoptosis regulator BCL2 family member (MCL-1), phorbol-12-myristate-13-acetate-induced protein 1 (NOXA), and the cell cycle was assessed in the U266 and RPMI 8226 cell lines. The gene discussed is PMAIP1; the disease is plasma cell myeloma.