While among the patients with HER2-positive breast cancer, 15-year OS was 70% (95% CI: 57–83) in the FEC14 group and 57% (95% CI: 43–72) in the FEC21 group (HR = 0.72, 95% CI: 0.39–1.35, p = 0.30); 15-year EFS was 57% (95% CI: 39–74) in the FEC14 group and 23% (95% CI: 7–39) in the FEC21 group (HR = 0.48, 95% CI: 0.28–0.84; p = 0.01). Here, ERBB2 is linked to breast cancer.