Toward the DNA methylation haplotype map of 11 common solid cancers

Area of Science:

• Genomics
• Epigenetics
• Cancer Biology

Background:

• Heterogeneous tumors exhibit methylation haplotype blocks (MHBs) at adjacent CpG sites, reflecting local epigenetic concordance.
• The pan-cancer dynamics and clinical significance of MHBs in gene dysregulation are not fully understood.

Purpose of the Study:

• To investigate the pan-cancer landscape of MHBs.
• To explore the association of MHBs with gene expression and tumor heterogeneity.
• To evaluate MHBs as potential biomarkers for cancer detection.

Main Methods:

• Profiling of 110 primary tumors across 11 common solid cancer types.
• Identification and characterization of 81,567 MHBs.
• Integrative bulk and single-cell analyses to link MHBs with gene expression.
• Analysis of MHB discordance in relation to driver mutations and inflammatory pathways.

Main Results:

• MHBs demonstrate high cancer-type specificity and enrichment in regulatory elements.
• MHBs associate with gene expression independently of mean methylation changes.
• MHB-associated genes are implicated in key oncogenic pathways (G2/M checkpoint, MYC targets, E2F signaling).
• MHB discordance correlates with driver mutations and inflammatory pathways.
• MHBs show promise as effective biomarkers for cancer detection.

Conclusions:

• MHBs are multimodal epigenetic regulators influencing transcriptional control and tumor heterogeneity.
• MHBs represent a valuable resource for understanding cancer epigenetics.
• MHBs hold potential for advancing liquid biopsy diagnostics and cancer detection.