Epigenetic alterations to Polycomb targets precede malignant transition in a mouse model of breast cancer

Sci Rep. 2018 Apr 3;8(1):5535. doi: 10.1038/s41598-018-24005-x.


Malignant breast cancer remains a major health threat to women of all ages worldwide and epigenetic variations on DNA methylation have been widely reported in cancers of different types. We profiled DNA methylation with ERRBS (Enhanced Reduced Representation Bisulfite Sequencing) across four main stages of tumor progression in the MMTV-PyMT mouse model (hyperplasia, adenoma/mammary intraepithelial neoplasia, early carcinoma and late carcinoma), during which malignant transition occurs. We identified a large number of differentially methylated cytosines (DMCs) in tumors relative to age-matched normal mammary glands from FVB mice. Despite similarities, the methylation differences of the premalignant stages were distinct from the malignant ones. Many differentially methylated loci were preserved from the first to the last stage throughout tumor progression. Genes affected by methylation gains were enriched in Polycomb repressive complex 2 (PRC2) targets, which may present biomarkers for early diagnosis and targets for treatment.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Biomarkers, Tumor / genetics
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology*
  • DNA Methylation
  • Disease Models, Animal*
  • Epigenesis, Genetic*
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic*
  • Gene Regulatory Networks*
  • Humans
  • Mice
  • Polycomb-Group Proteins / genetics*
  • Precancerous Conditions / genetics
  • Precancerous Conditions / metabolism
  • Precancerous Conditions / pathology
  • Prognosis


  • Biomarkers, Tumor
  • Polycomb-Group Proteins