ERBB2 and breast cancer: ,2 Overactivation of this pathway is often found in hormone receptor (HR) positive, human epidermal growth factor receptor-2 (HER2) negative breast cancer.3, 4, 5 In November 2023, the US Food and Drug Administration granted approval of capivasertib for use in combination with fulvestrant for the treatment of HR-positive, HER2-negative breast cancer.