Abstract
The clinical heterogeneity of patients with myelodysplastic syndromes suggests that there must also be a broad range of pathogenetic abnormalities that underlie this disorder. It is clear that the molecular abnormalities associated with MDS are vast, as are the functional abnormalities within the hematopoietic compartment. This implies that there may also be significant differences in the cell of origin and varying degrees of aberrant communication with the microenvironment in individual patients. It is only through recent advances in flow cytometry, DNA sequencing, and high throughput analysis of the genome, proteome, and RNA expression profiles that we can make these general but profound statements about the spectrum of abnormalities in MDS patients.