ERBB2 and breast cancer: The mean 5-year DRFS was 80.9% ± 2.1% for HR+/HER2+ breast cancer, 82.1% ± 0.7% for HR+/HER2− breast cancer, 69.9% ± 3.9% for HR−/HER2+, and 65.9% ± 2.3% for HR−/HER2− breast cancer in stage B.