P916: COEXISTENCE OF ≥2 HIGH-RISK MOLECULAR ABNORMALITIES SUPERVENES THE PROGNOSTIC VALUE OF THE REVISED INTERNATIONAL STAGING SYSTEM FOR MYELOMA: REAL-WORLD DATA ANALYSIS FROM THE GREEK MYELOMA STUDY GROUP. (23rd June 2022) - Katodritou, E.; Dalampira, D.; Triantafyllou, T.; Gavriatopoulou, M.; Delimpasi, S.; Pouli, A.; Papadopoulou, T.; Verrou, E.; Sevastoudi, A.; Tsirou, K.; Katsika, L.; Douganiotis, G.; et al.