Cytogenetics are the main predictors of outcome in patients with AML. In fact, a monosomy 5 or del (5q) as single aberration are poor prognostic markers. Overall, the complete response rate for conventionally treated patients with newly-diagnosed AML with chromosome 5 abnormalities is about 31% to 37 % and all patients rapidly relapse if not rescued by allogeneic HSCT. The situation is almost similar in patients with high-risk MDS.Vidaza® has been shown in clinical trials to achieve remission rates in about 29% (CR+PR) of the patients while a total of 49% achieve improvement of blood counts.Revlimid® is also able to achieve complete remissions in advanced MDS and even overt leukemia with or without chromosome 5 abnormalities. Nevertheless, response rates are lower compared to low-risk MDS (IPSS Low/INT-1). Therefore, Revlimid® seems to be too weak as a single agent, but a promising compound for a combination therapy.