DNA methylation dynamics during B cell maturation underlie a continuum of disease phenotypes in chronic lymphocytic leukemia

Nat Genet. 2016 Mar;48(3):253-64. doi: 10.1038/ng.3488. Epub 2016 Jan 18.

Abstract

Charting differences between tumors and normal tissue is a mainstay of cancer research. However, clonal tumor expansion from complex normal tissue architectures potentially obscures cancer-specific events, including divergent epigenetic patterns. Using whole-genome bisulfite sequencing of normal B cell subsets, we observed broad epigenetic programming of selective transcription factor binding sites coincident with the degree of B cell maturation. By comparing normal B cells to malignant B cells from 268 patients with chronic lymphocytic leukemia (CLL), we showed that tumors derive largely from a continuum of maturation states reflected in normal developmental stages. Epigenetic maturation in CLL was associated with an indolent gene expression pattern and increasingly favorable clinical outcomes. We further uncovered that most previously reported tumor-specific methylation events are normally present in non-malignant B cells. Instead, we identified a potential pathogenic role for transcription factor dysregulation in CLL, where excess programming by EGR and NFAT with reduced EBF and AP-1 programming imbalances the normal B cell epigenetic program.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • B-Lymphocytes / immunology
  • B-Lymphocytes / metabolism*
  • Binding Sites
  • CpG Islands / genetics
  • DNA Methylation / genetics*
  • Epigenesis, Genetic*
  • Female
  • Gene Expression Regulation, Leukemic
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Leukemia, Lymphocytic, Chronic, B-Cell / genetics*
  • Leukemia, Lymphocytic, Chronic, B-Cell / immunology
  • Leukemia, Lymphocytic, Chronic, B-Cell / pathology
  • Male
  • Middle Aged
  • Neoplasm Proteins / biosynthesis
  • Neoplasm Proteins / genetics
  • Phenotype
  • Promoter Regions, Genetic

Substances

  • Neoplasm Proteins