Aberrant methylation of tumor suppressor genes in patients with refractory anemia with ring sideroblasts.
ABSTRACT This study evaluates the incidence and prognostic impact of aberrant methylation of 25 tumor suppressor genes in 40 patients with RARS, a MDS subtype, by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) assay. Methylation of at least one gene was detected in 18 patients (45%). The genes methylated were CDKN2B (20%), RASSF1 (18%), RARB (10%), CDH13 (7.5%) and FHIT (5%). Patients with at least one methylated gene had a significantly shorter OS than patients without methylated genes. Aberrant methylation is a frequent event in patients with RARS as in patients with high-risk MDS appears to confer a worse prognosis.
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ABSTRACT: Multiplex Ligation-dependent Probe Amplification (MLPA) assay is a recently developed technique able to evidence variations in the copy number of several human genes. Due to this ability, MLPA can be used in the molecular diagnosis of several genetic diseases whose pathogenesis is related to the presence of deletions or duplications of specific genes. Moreover, MLPA assay can also be used in the molecular diagnosis of genetic diseases characterized by the presence of abnormal DNA methylation. Due to the large number of genes that can be analyzed by a single technique, MLPA assay represents the gold standard for molecular analysis of all pathologies derived from the presence of gene copy number variation. In this review, the main applications of the MLPA technique for the molecular diagnosis of human diseases are described.International Journal of Molecular Sciences 01/2012; 13(3):3245-76. · 2.46 Impact Factor
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ABSTRACT: Myelodysplastic syndromes (MDS) are clonal stem cell disorders which frequently show a hypercellular dysplastic bone marrow (BM) associated with inefficient hematopoiesis and peripheral cytopenias due to increased apoptosis and maturation blockades. Currently, little is known about the role of cell proliferation in compensating for the BM failure syndrome and in determining patient outcome. Here, we analyzed the proliferation index (PI) of different compartments of BM hematopoietic cells in 106 MDS patients compared to both normal/reactive BM (n = 94) and acute myeloid leukemia (AML; n = 30 cases) using multiparameter flow cytometry. Our results show abnormally increased overall BM proliferation profiles in MDS which significantly differ between early/low-risk and advanced/high-risk cases. Early/low-risk patients showed increased proliferation of non-lymphoid CD34(+) precursors, maturing neutrophils and nucleated red blood cells (NRBC), while the PI of these compartments of BM precursors progressively fell below normal values towards AML levels in advanced/high-risk MDS. Decreased proliferation of non-lymphoid CD34(+) and NRBC precursors was significantly associated with adverse disease features, shorter overall survival (OS) and transformation to AML, both in the whole series and when low- and high-risk MDS patients were separately considered, the PI of NRBC emerging as the most powerful independent predictor for OS and progression to AML. In conclusion, assessment of the PI of NRBC, and potentially also of other compartments of BM precursors (e.g.: myeloid CD34(+) HPC), could significantly contribute to a better management of MDS.PLoS ONE 01/2012; 7(8):e44321. · 3.73 Impact Factor