ERBB2 and breast cancer: However, HR+/HER2− breast cancer showed a significantly better DRFS rate than did HR+/HER2+ breast cancer in stage A. Mean 5-year DRFS in stage A was 86.7% ± 1.1% for HR+/HER2+ breast cancer, 91.4% ± 0.3% for HR+/HER2− breast cancer, 84.5% ± 1.9% for HR−/HER2+ breast cancer, and 87.9% ± 0.6% for HR−/HER2− breast cancer.