Chromosome copy number variation and breast cancer risk.

Breast cancer is the most frequent cancer among women. It is caused by genetic and environmental factors. Whereas mutations in high-penetrance susceptibility genes have been identified in familial breast cancer and several single nucleotide polymorphisms (SNPs) have been shown to be associated with both familial and sporadic breast cancer risk, the impact of genomic copy number variants (CNVs) on breast cancer risk has so far poorly been studied. An example of a CNV affecting the tumor suppressor gene MTUS1 that has been shown to be associated with familial breast cancer risk is given. Moreover, we discuss CNVs affecting detoxification genes like GSTM1 and GSTT1 whose association with breast cancer risk is controversial. Finally, the potential of array-based genome-wide CNV association studies is discussed. Copyright 2009 S. Karger AG, Basel.