Exome Sequencing Analysis Identifies Copy Number Variants Linked to Breast Cancer Susceptibility

Researchers from the University of Oulu in Finland investigate the role of copy number variants (CNVs) in inherited breast cancer susceptibility in a paper in PLOS Genetics. While CNVs are known to cause or predispose people to various diseases, their role in breast cancer susceptibility is largely unexplored. Through a whole-exome sequencing-based analysis of rare CNVs in 98 high-risk Northern Finnish breast cancer cases, the researchers aimed to tease out the role in breast cancer risk. They uncovered three recurrent alterations within this cohort: a 31 kb deletion co-occurring with a retrotransposon insertion in RAD52, a 13.4 kb deletion in HSD17B14, and a 64 kb partial duplication of RAD51C. These genes each encode proteins involved in pathways previously found essential for breast cancer development. By further genotyping a cohort of geographically matched cases and controls, the researchers found that the RAD52 and HSD17B14 deletions were significantly enriched among cases thought have higher risk of hereditary breast cancer. According to the authors, their findings highlight the importance of studying CNVs alongside single nucleotide variants when searching for genetic factors underlying hereditary disease predisposition.