Methylation of TET2, CBL and CEBPA in Ph-negative myeloproliferative neoplasms

Abstract

A loss-of-function mutation of TET2, CBL and CEBPA has been implicated in the pathogenesis or leukaemic transformation of myeloproliferative neoplasm. As tumour suppressor genes may potentially be inactivated by promoter hypermethylation, the authors studied the methylation status of these genes in three cell lines and diagnostic marrow samples from 45 patients with myeloproliferative neoplasm (MPN) (essential thrombocythaemia, N=34; polycythaemia vera, N=7 and primary myelofibrosis, N=4) by methylation-specific PCR. TET2 was heterozygously methylated in MEG-01 and K562 but completely unmethylated in HEL. On the other hand, both CBL and CEBPA were completely unmethylated in all three cell lines. In the primary marrow samples, methylation of TET2 occurred in two (5.9%) patients with essential thrombocythaemia (4.4% of all patients), both without JAK2 V617 mutation, but not in polycythaemia vera or primary myelofibrosis. There was no association between TET2 methylation with the type of MPN (p=0.713). Hypermethylation of CBL or CEBPA was not detected in any patients. In summary, methylation of TET2, CBL and CEBPA is infrequent in MPN at diagnosis. The role of methylation of these genes at the time of leukaemic transformation warrants further study.

Epigenomic profiling in polycythaemia vera and essential thrombocythaemia shows low levels of aberrant DNA methylation

“…In accordance with the literature, we did not find a differential methylation pattern of genes XAF1, JUNB, CDH13, TET2, CBL and CEBPA in MPN 17 18…”

“…Many other genes have already been analysed at the methylation level in MPN: XAF1, JUNB, CDH13, TET2, CBL and CEBPA among them 17 18. We analysed methylation of these genes and did not find any differential pattern (data not shown).…”

TET2 expression level and 5-hydroxymethylcytosine are decreased in refractory cytopenia of childhood

“…In fact, a predominant demethylated pattern of the promoter was found in both groups. Several studies have analyzed the methylation status of TET2 promoter with similar results in spite of different methodological approaches [15,34]. In this study methylation profile of TET2 was evaluated by an originally designed HRM PCR analysis.…”

TET2promoter methylation in low-grade diffuse gliomas lackingIDH1/2mutations: Figure 1

“…Recent studies suggest that TET2 is a tumour suppressor gene, since TET2 mutations have been detected in 10–25% of AMLs, myelodysplastic syndrome and myeloproliferative neoplasms,15 17 and TET2 promoter methylation has been reported in a small fraction (4.4%) of myeloproliferative neoplasms 20. Loss at the TET2 locus (4q24) has been observed in a small fraction of glioblastomas (2%) 33.…”

“…Methylation-specific PCR was carried out in 35 low-grade diffuse gliomas without IDH1/2 mutations and 38 low-grade diffuse gliomas with IDH1/2 mutations, to assess TET2 promoter methylation using primers reported by Chim et al 20. For each methylation-specific PCR reaction, we included universal methylated DNA (Chemicon International, Temecula, California, USA) as positive control, and normal blood DNA as negative control 24.…”