Global hypomethylation is an independent prognostic factor in diffuse large B cell lymphoma

Eileen Wedge, Jakob Werner Hansen, Christian Garde, Fazila Asmar, Dorte Tholstrup, Søren Sommer Kristensen, Helga D Munch-Petersen, Elisabeth Ralfkiaer, Peter Brown, Kirsten Grønbaek, Lasse Sommer Kristensen

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Abstract

Global hypomethylation has been linked to disease progression in several cancers, but has not been reported for Diffuse Large B Cell Lymphoma (DLBCL). This study aimed to assess global methylation in DLBCL and describe its prognostic value. Mean LINE1 methylation, a validated surrogate measure for global methylation, was measured in DNA from 67 tumor biopsies. Additionally, cell-free circulating DNA (cfDNA) in plasma samples from 74 patients was tested to assess the feasibility of global hypomethylation as a biomarker in liquid biopsies. LINE1 methylation was assessed using a commercially available kit, based on pyrosequencing of PCR amplified bisulfite-treated DNA. Global hypomethylation was detected in a subset of cases and was associated with poor overall survival in both tumor biopsies (P = .001) and cfDNA (P = .009). It was the strongest risk factor in multivariate analysis in both biopsies (HR: 10.65, CI: 2.03-55.81, P = .005) and cfDNA (HR: 11.87, CI: 2.80-50.20, P = .001), outperforming conventional clinical risk factors. Finally, hierarchical cluster analyses were performed for the cfDNA samples using previously published gene-specific methylation data. This analysis shows that global hypomethylation co-occurs with other epigenetic abnormalities, including DAPK1 promoter hypermethylation. In conclusion, we have shown that global hypomethylation is strongly associated with poor survival in DLBCL both when present in tumor biopsy DNA and when detected in plasma cfDNA, and has potential for clinical application as a prognostic biomarker.

OriginalsprogEngelsk
TidsskriftAmerican Journal of Hematology
Vol/bind92
Udgave nummer7
Sider (fra-til)689-694
Antal sider6
ISSN0361-8609
DOI
StatusUdgivet - jul. 2017

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