EZH2 is overexpressed in breast tumors with a BRCA1-like DNA copy number profile

Purpose: The polycomb group protein EZH2 is an epigenetic repressor through its trimethylase activity of H3K27me3 and overexpression of EZH2 is associated with aggressive types of breast cancer. We previously reported that breast tumors deriving from a BRCA1-deficient mouse model show high levels of EZH2. Human BRCA1-mutated breast tumors carry a specific DNA copy-number signature („BRCA1-like“) which is also found in tumors with a loss of BRCA1 function by other mechanism such as BRCA1-promoter methylation. Here, we explored whether EZH2 is overexpressed in human BRCA1-like breast tumors. Patients and methods:…