Publication Date
2020
Journal or Book Title
Epigenetics
Abstract
While changes in DNA methylation are known to occur early in breast carcinogenesis and the landscape of breast tumour DNA methylation is profoundly altered compared with normal tissue, there have been limited efforts to identify DNA methylation field cancerization effects in histologically normal breast tissue adjacent to tumour. Matched tumour, histologically normal tissue of the ipsilateral breast (ipsilateral-normal), and histologically normal tissue of the contralateral breast (contralateral-normal) were obtained from nine women undergoing bilateral mastectomy. Laser capture microdissection was used to select epithelial cells from normal tissue, and neoplastic cells from tumour for genome-scale measures of DNA methylation with the Illumina HumanMethylationEPIC array. We identified substantially more CpG loci that were differentially methylated between contralateral-normal and tumour (63,271 CpG loci q < 0.01), than between ipsilateral-normal and tumour (38,346 CpG loci q < 0.01). We identified differential methylation in ipsilateral-normal relative to contralateral-normal tissue (9,562 CpG loci p < 0.01). In this comparison, hypomethylated loci were significantly enriched for breast cancer-relevant transcription factor binding sites including those for ESR1, FoxA1, and GATA3 and hypermethylated loci were significantly enriched for CpG island shore regions. In addition, progression of shore hypermethylation was observed in tumours compared to matched ipsilateral normal tissue, and these alterations tracked to several well-established tumour suppressor genes. Our results indicate an epigenetic field effect in surrounding histologically normal tissue. This work offers an opportunity to focus investigations of early DNA methylation alterations in breast carcinogenesis and potentially develop epigenetic biomarkers of disease risk.
DOI
https://doi.org/10.1080/15592294.2020.1747748
Pages
1093-1106
Volume
15
Issue
10
License
UMass Amherst Open Access Policy
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Recommended Citation
Muse, Meghan E.; Titus, Alexander J.; Salas, Lucas A.; Wilkins, Owen M.; Mullen, Chelsey; Gregory, Kelly J.; Schneider, Sallie S.; Crisi, Giovanna M.; Jawale, Rahul M.; Otis, Christopher N.; Christensen, Brock C.; and Arcaro, Kathleen F., "Enrichment of CpG island shore region hypermethylation in epigenetic breast field cancerization" (2020). Epigenetics. 12.
https://doi.org/10.1080/15592294.2020.1747748