5-Hydroxymethylcytosine Profiling of Cell-Free DNA Identifies Bivalent Genes That Are Prognostic of Survival in High-Risk Neuroblastoma [5-hmC]

Using bivalent genes defined in vitro, a bivalent signature was established in three publicly available cohorts of patients with neuroblastoma through gene set variation analysis. Differences between tumors with high or low bivalent signatures were assessed by the Kaplan-Meier method and Cox proportional hazards models. Results: In cfDNA compared with tumor biopsy derived 5-hmC profiles, we found in- creased 5-hmC deposition on Polycomb Repressive Complex 2 target genes, a finding previously described in the context of bivalent genes.

We identified 313 genes that bore bivalent chromatin marks, were enriched for mediators of neuronal differentiation, and were transcriptionally repressed across a panel of heterogeneous neuroblastoma cell lines. In three distinct clinical cohorts, low bivalent signature was significantly and independently associated with worse clinical outcome in patients with high-risk neuroblastoma. Conclusion: Low expression of bivalent genes is a biomarker of worse outcome in patients with high-risk neuroblastoma.