ESR1 and breast cancer: Among breast cancer cases, triple negative hormone receptor status (ER− PR− HER2−) patients and HER2+ patients had higher IPR (0.50%, 95% CI: 0.38–0.62 and 0.49%, 95% CI: 0.39–0.59, respectively) compared to those with ER+ PR+ HER2− status (0.10%, 95% CI: 0.08–0.12).