ABSTRACT
The myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematopoietic disorders with unfavorable prognosis due to complications of cytopenias or because of transformation into acute myeloid leukemia (AML) (1,2). Cells of all three hematopoietic lineages show quantitative and qualitative abnormalities. Morphological dysplasia, impaired differentiation, and defective cellular functions as well as genetic instability are the fundamental abnormalities shared by the MDS clone. Conceivably, these abnormalities represent different facets of the abnormal clone. The precise etiology of primary MDS remains unknown, but it is believed to result from transformation at the level of the pluripotent hematopoietic stem cells (1).
