Myelodysplastic Syndrome with Deletion 5q Abnormality and Its Treatment

The clinical features of myelodysplastic syndrome (MDS) associated with an interstitial deletion of chromosome 5q(31-33) are well characterized; however, the underlying molecular events of pathogenesis remain elusive. This class of immunomodulatory drugs has gained much interest after the report of high hematologic and cytogenetic response rates in patients with MDS and 5q abnormalities treated with lenalidomide. Lenalidomide demonstrates potent immunomodulatory properties through several pathways, including enhanced T-cell activation and augmentation of natural killer cell activity. Recent studies also report potential selectivity of lenalidomide on cell lines with 5q abnormality. This review outlines the mechanism of action of lenalidomide and the key trials in MDS associated with 5q deletion syndrome. Potential candidate genes mapped to the critically deleted region of chromosome 5q are described, and the roles of gene expression profiling and single-nucleotide polymorphism analysis are summarized herein.