Apport de l'hybridation in situ en fluorescence (FISH) pour la détection des anomalies cytogénétiques dans les syndromes myélodysplasiques

The myelodysplastic syndromes (MDS) are heterogeneous group of clonal disorders characterized by cytopenias due to ineffective hematopoiesis and increased apoptosis. New treatments are now available. The therapeutic decision depends on the type of MDS and the International Prognosis scoring System (IPSS) based on the cytopenias, the percentage of blasts in the bone marrow and cytogenetic abnormalities. Younger “high risk” patients can benefit of cytotoxic drugs (as leukemic patients) and other available new treatments including demethylating agents (5-azacytidine). Low risk patients with the chromosome 5 long arm deletion can benefit of immunomodulatory agent as Lenalidomide (Revlimid®) alone or in combination with other drugs. Cytogenetic study of the bone marrow is used in clinical practice to identify abnormal clones at diagnosis and to establish the prognostic score. Performed on proliferate cells, metaphase cytogenetic identify clonal abnormalities in about 50% of cases. Those abnormalities are various at diagnosis and could be used to evaluate the efficacy of treatments. Fluorescence in situ hybridization (FISH) with specific gene target probes improve the abnormalities detection and contribute to the better follow-up.