Breast cancer is the most common invasive cancer in females worldwide and in Asian countries. Common variants found by genome-wide association studies (GWAS) only explain approximately 16% of the heritability of breast cancer: therefore, it is important to examine rare/low-frequency variants in GWAS-identified loci which may also contribute to breast cancer risk. Previous studies have reported that genetic variants with lower allele frequency are more likely to be functional than common variants in coding regions. In future studies, the contribution of observed rare variants will be estimated more clearly when additive and recessive genetic variants will be investigated using sequencing technology, eQTL studies, and improved statistical methods in large samples.
Keywords: Breast cancer; Genome-wide association studies (GWAS); Rare coding variant.