To extend findings of breast cancer association studies that have primarily been conducted in European-ancestry populations, Wei Zheng and colleagues systematically examined the association of known breast cancer susceptibility loci in east Asian women (Hum. Mol. Genet. doi:10.1093/hmg/ddt089, 27 March 2013). They genotyped 70 SNPs at 67 known susceptibility loci in 23,637 breast cancer cases and 25,579 controls of east Asian ancestry from the Asia Breast Cancer Consortium (ABCC) as well as Asian samples from COGS. They found that variants at 31 of these loci showed nominal association with breast cancer risk and that 21 of these met a Bonferroni-corrected significance level. This study offers the most comprehensive analysis of breast cancer risk variants in east Asians so far, but further studies and fine mapping of these regions in both European and Asian populations are needed to characterize population-specific differences in breast cancer susceptibility.