ESR1 and breast cancer: Mavaddat et al. developed a PRS with 313 SNPs optimized for estrogen receptor (ER)-specific breast cancer, reporting an ORxSD of 1.61 (95% CI: 1.57–1.65) and an AUC of 0.630 (95% CI: 0.628–0.651) in a European cohort (Mavaddat et al., 2019).