DNA defects, epigenetics, and gene expression in cancer-adjacent breast: a study from The Cancer Genome Atlas

RNA expression patterns in the breast tissue adjacent to where tumors are surgically removed are linked to patient survival outcomes. A research team led by Melissa Troester from the University of North Carolina at Chapel Hill, USA, looked for genomic alterations in the healthy, benign-looking breast tissue found more than 2 centimeters from the margin of where cancer had been cut out and treated with radiation. Approximately 40% of the 142 tissue samples analyzed harbored defects in DNA copy number, sequence, methylation, or RNA sequence. However, the only characteristic significantly associated with 10-year survival rates in patients was a particular expression profile of messenger RNA known as “active” and this connection held up only in women with a subtype of breast cancer called ER-positive. In this population, RNA profiling could help predict survival outcomes.