Constitutional and somatic methylation status of DMRH19 and KvDMR in Wilms tumor patients

Abstract

The most frequent epigenetic alterations in Wilms tumor (WT) occur at WT2, assigned to 11p15. WT2 consists of two domains: telomeric domain 1 (DMRH19) that contains the IGF2 gene and an imprinted maternally expressed transcript (H19) and centromeric domain 2 (KvDMR) that contains the genes KCNQ1, KCNQ1OT1 and CDKN1C. In this work, we used pyrosequencing and MS-MLPA to compare the methylation patterns of DMRH19/KvDMR in blood and tumor samples from 40 WT patients. Normal constitutional KvDMR methylation indicated that most of the epigenetic alterations in WT occur at DMRH19. Constitutional DMRH19 hypermethylation (HM DMRH19) was observed in two patients with Beckwith-Wiedemann syndrome. Pyrosequencing and MS-MLPA showed HM DMRH19 in 28/34 tumor samples: 16/34 with isolated HM DMRH19 and 12/34 with concomitant HM DMRH19 and KvDMR hypomethylation, indicating paternal uniparental disomy. With the exception of one blood sample, the MS-MLPA and pyrosequencing findings were concordant. Diffuse or focal anaplasia was present in five tumor samples and was associated with isolated somatic HM DMRH19 in four of them. Constitutional 11p15 methylation abnormalities were present in 5% of the samples and somatic abnormalities in the majority of tumors. Combined analysis of DMRH19/KvDMR by pyrosequencing and MS-MLPA is beneficial for characterizing epigenetic anomalies in WT, and MS-MLPA is useful and reliable for estimation of DNA methylation in a clinical setting.

Promoter hypermethylation using 24-gene array in early head and neck cancer

“…We believe these high correlation percentages justify the reliability of MS-MLPA. [18][19][20][21][22][23][24][25] The presence of two or more hypermethylated genes proved to be an independent predictor for better disease specific survival in our cohort of early OSCC, which seems paradoxical since promoter hypermethylation leads to gene silencing, as mentioned above. However, multiple studies found correlations between promoter hypermethylation of TSGs and increased survival in lung, oral and gastric cancer.…”

Beckwith-Wiedemann Syndrome: Growth Pattern and Tumor Risk according to Molecular Mechanism, and Guidelines for Tumor Surveillance

“…These types of tumors frequently displayed 11p15 pUPD (i.e. loss of the maternal 11p15 and duplication of the paternal allele) or a loss of imprinting in the telomeric domain (ICR1 GOM) [1,2,5,38,40,41,42,43,44,45,46]. …”

The pathophysiology of bilateral and multifocal Wilms tumors: What we can learn from the study of predisposition syndromes

“…Another study found 11p15.5 alterations in blood in four out of 105 (3.8%) patients with WT who did not meet diagnostic criteria for BWSp 18 . Several smaller single institutional studies each reported a similar prevalence of constitutional 11p15.5 alterations (3–5%), although syndromic features were not reported in the patients included 19,20 . One study suggested that up to 25% of nonsyndromic patients with WT may have ICR1 mGOM in blood when a lower cut‐off than two standard deviations from normal for methylation levels is used 21 .…”