Among patients with luminal and patients with HER2-positive breast cancer, tDD EC/D improved BCRFS compared to FEC/D (HR = 0.83, 95% CI 0.65–1.05, p = 0.12 and HR = 0.53, 95% CI 0.30–0.93, p = 0.026, respectively). The gene discussed is ERBB2; the disease is breast carcinoma.