Subtyping Burkitt Lymphoma by DNA Methylation.

Area of Science:

• Oncology
• Epigenetics
• Virology

Background:

• Burkitt lymphoma (BL) is an aggressive B-cell malignancy with historically defined variants.
• Epstein-Barr virus (EBV) positivity frequency differs across BL variants.
• Understanding BL heterogeneity is crucial for targeted therapies.

Purpose of the Study:

• To identify subgroups of Burkitt lymphoma based on DNA methylation patterns.
• To investigate the influence of Epstein-Barr virus (EBV) status on DNA methylation profiles.
• To correlate methylation subgroups with clinical and molecular features.

Main Methods:

• DNA methylation profiling of 96 BL cases, 17 BL cell lines, and 6 EBV-transformed lymphoblastoid cell lines using Illumina BeadChip arrays.
• Clustering analysis to identify methylation-based subgroups.
• Analysis of CpG methylation patterns, epigenetic age, and gene regulatory elements.

Main Results:

• Four distinct DNA methylation subgroups were identified: two predominantly EBV-positive (BL-mC1, BL-mC2) and two predominantly EBV-negative (BL-mC3, BL-mC4).
• EBV-positive subgroups exhibited increased DNA methylation and epigenetic age.
• Hypermethylated CpGs in EBV-positive BL were associated with Polycomb Repressive Complex 2 marks, while hypomethylated CpGs in EBV-negative BL linked to B-cell receptor signaling.
• EBV-associated hypermethylation impacted regulatory regions of key BL-mutated genes (e.g., CCND3, TP53) and superenhancers.

Conclusions:

• Epstein-Barr virus (EBV) status is the primary driver of DNA methylation-based subgrouping in Burkitt lymphoma.
• DNA methylation patterns reveal distinct epigenetic landscapes associated with EBV positivity.
• These findings suggest EBV-driven hypermethylation may influence oncogenic pathways and compensate for lower mutational burden in EBV-positive BL.