title: Aberrant methylation of the negative regulators RASSFIA, SHP-1 and SOCS-1 in myelodysplastic syndromes and acute myeloid leukaemia.
abstract: Mutations in the receptor tyrosine kinase (RTK/RAS) signalling pathway frequently provide a proliferative signal in myeloid malignancies. However, the role of RASSF1A, SHP-1 and SOCS-1, negative regulators of RTK/RAS signalling, has not been extensively investigated in the myelodysplastic syndromes (MDS) or acute myeloid leukaemia (AML). This study employed methylation-specific polymerase chain reaction (MS-PCR) to determine if aberrant promotor methylation of RASSF1A, SHP-1 and SOCS-1 is involved in the pathogenesis of myeloid malignancies. Patients with MDS (n = 107), AML (n = 154) and juvenile myelomonocytic leukaemia (JMML, n = 5) were investigated, together with 15 normal controls. Primers were located in the promotor region of each gene as well as within exon 2 of SOCS-1. Methylation of RASSF1A was found in five of 55 (9%) MDS cases, but not in any of 57 AML cases studied. RASSF1A methylation was present in one case (20%) of JMML. SHP-1 methylation was present in 13 of 121 (11%) AML cases but was not found in MDS or JMML. SOCS-1 promoter methylation was present in eight of 74 (11%) MDS patients but was not seen in JMML or AML. Importantly, RAS mutations and RASSF1A and SOCS-1 methylation were mutually exclusive indicating that approximately 30% of MDS cases had a defect of the RTK/RAS pathway and its negative regulation. Finally, SOCS-1 exon 2 methylation may not be pathogenetically relevant, since it was detected in samples from normal individuals and did not correlate with promotor methylation.
authors.affiliation: Academic Unit of Haematology, Division of Genomic Medicine, Henry Wellcome Laboratories for Medical Research, Sheffield, UK.
authors.forename: M F
authors.initials: MF
authors.lastname: Johan
authors.forename: D T
authors.initials: DT
authors.lastname: Bowen
authors.forename: M E
authors.initials: ME
authors.lastname: Frew
authors.forename: A C
authors.initials: AC
authors.lastname: Goodeve
authors.forename: J T
authors.initials: JT
authors.lastname: Reilly
mesh_terms: D000208:Acute Disease; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D007951:Leukemia, Myeloid / Q000235:genetics; D009190:Myelodysplastic Syndromes / Q000235:genetics*; D009363:Neoplasm Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000379:methods; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: D004273:DNA, Neoplasm; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; C411762:RASSF1 protein, human; D012097:Repressor Proteins; C108944:SOCS1 protein, human; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D025521:Tumor Suppressor Proteins; C509249:PTPN6 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases