271 ACQUISITION OF CYTOGENETIC ABNORMALITIES IN PATIENTS WITH IPSS LOW AND INTERMEDIATE-1 RISK. STUDY FROM THE SPANISH GROUP OF MYELODYSPLASTIC SYNDROME. Issue 1 (April 2015) - Merchan, B.; Ortega, M.; Llamas-Poyato, M.J.; Cortés, M.; Arnan, M.; Cerveró, C.; Montoro, J.; Gimenez, T.; López, M.; Arenillas, L.; Valcarcel, D.