P855: SYNERGISTIC EFFICACY OF COMBINED SUMOYLATION AND PROTEASOME INHIBITION IN MULTIPLE MYELOMA. (23rd June 2022) - Keller, U.; Heynen, G.; Baumgartner, F.; Heider, M.; Patra, U.; Braune, J.; Mertins, P.; Müller, S.; Bassermann, F.; Krönke, J.; Wirth, M.