The only known curative therapy is an allogeneic bone marrow transplant of which the vast majority of patients with this disorder are not candidates. Currently three drugs have been approved for the treatment of MDS: azacytidine, decitabine and lenalidomide for low grade patients with a chromosome 5q abnormality. Azacytidine and decitabine have been demonstrated to improve blood counts, improve the quality of life, and decrease the risk of progression to AML or death in a sizable minority of MDS patients. A recent study of MDS patients who had responded clinically to decitabine revealed that their bone marrow biopsies still showed stromal abnormalities such as increased angiogenesis. Lenalidomide acts at the level of the stromal - marrow cell interaction. It is hypothesized that the combination of decitabine with lenalidomide may show synergistic results.