Large-scale genetic studies conducted over the last decade discovered dozens of genetic variants that are associated with increased risk for breast cancer (BC). These BC-risk variants can be used to calculate a genetic risk score (called ‘polygenic risk score’ – PRS) which has the predictive capacity to detect women with significantly elevated genetic risk for BC. However, these genetic studies were mostly done on women of European (EUR) ancestry, and the predictive performance of EUR-based BC PRS declines when applied to women of other ethnicities. Here, we systematically evaluated the performance of EUR-based BC PRS on Ashkenazi Jewish (AJ) women in Israel. Our results demonstrate that these BC PRSs perform well on this ethnic group, and can identify AJ women with markedly elevated risk for BC.  Our study holds promise for improving early detection of breast cancer in Israel. (By Prof. Rani Elkon, https://jmg.bmj.com/content/early/2023/07/13/jmg-2023-109185 )