ESR1 and breast neoplasm: Furthermore, we observed that higher levels of IA ancestry and a lower European ancestry fraction was associated with higher odds of ER+/HER2+ breast tumors (IA ancestry fraction: OR= 1.93, 95% CI, 1.13-3.32, p=0.0154; European ancestry fraction: OR= 0.46, 95% CI, 0.26-0.82, p= 0.00882).