ERBB2 and breast carcinoma: In a multivariable analysis of a retrospective cohort study of 3333 women with stage I–II (cT1–T2) HER2+ breast cancer treated with upfront surgery without neoadjuvant therapy, T1c and T2 patients had a 3.4- and 6.3-fold increased incidence of node-positive disease relative to T1a patients (T1c odds ratio [OR]: 3.37, 95% CI 2.35–4.85; T2 OR: 6.34, 95% CI 4.41–9.10) [17].