Based on these long-term safety analyses of three randomized phase II and III studies (PALOMA1, 2, 3), palbociclib plus endocrine therapy has not shown specific cumulative or delayed toxicities to HR-positive, HER2-negative ABC, supporting the ongoing investigation of palbociclib plus endocrine therapy in early breast cancer (NCT02513394) 63. The gene discussed is ERBB2; the disease is breast cancer.