ERBB2 and metastatic malignant neoplasm in the lymph nodes: The following six variables were chosen as prognostic factors for inclusion in the Cox proportional hazard model: age (<35 vs ⩾35 years), clinical stage at diagnosis (IIA and IIB, or IIIA vs IIIB or IIIC), histological grade (1 vs 2 and 3), HER2 status (positive vs negative), clinical response (CR, PR vs SD, PD), and the number of lymph node metastases (0 vs 1–3 vs ⩾4).