ESR1 and breast cancer: As to BC subtypes, TILs also indicated survival benefit in TNBC (HR = 0.82; 95% CI, 0.76–0.88 for DFS; HR = 0.79; 95% CI, 0.71–0.87 for OS) and HER2+ patients (HR = 0.90; 95% CI, 0.82–0.99 for DFS), but not in estrogen-receptor positive (ER+) patients (HR = 1.01; 95% CI, 0.94–1.07 for DFS; HR = 1.09; 95% CI, 0.98–1.21 for OS; Fig 3).