Abstract 2018: Genome-wide analysis of DNA methylation and copy number changes in breast cancers.

Abstract Epigenetic modifications are known to be critical in regulating normal developmental processes and cellular differentiation. DNA methylation of CpG dinucleotides is a well-characterized epigenetic marker frequently associated with transcriptional silencing. CpG dinucleotides are non-randomly distributed throughout the genome with regions enriched for CpGs being known as CpG islands. It is now well established that epigenetic inactivation of tumor suppressor genes can occur by CpG island promoter methylation. For example, BRCA1 promoter methylation occurs in approximately 10 - 15% of all breast cancers and is associated with gene silencing. Recent technological advances have enabled DNA methylation to be profiled genome-wide. Using the Infinium 450 thousand probe arrays, we have studied DNA methylation and copy number changes to discover new markers of potential clinical relevance in breast cancer. Expression analyses by immunohistochemisty on tissue arrays for subtype-specific markers (ER, PR, HER2, Ki-67, EGFR, CK5/6, CK8, CK18, MUC1 and Claudin-3) carried out previously were used to establish DNA methylation markers of breast cancer subtypes. This integrated approach is presented in clinical context with available data on histological grade, disease stage and breast cancer-specific survival outcomes. Citation Format: Olafur A. Stefansson, Sebastian Moran, Antonio Gomez, Sergi Sayols Puig, Jorunn Eyfjord, Manel Esteller. Genome-wide analysis of DNA methylation and copy number changes in breast cancers. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2018. doi:10.1158/1538-7445.AM2013-2018