ERBB2 and breast carcinoma: Furthermore, a pooled analysis of 764 patients with pT1a-b pN0 breast cancer showed that HER2-positive status was associated with a significant detrimental effect on relapse-free and distant relapse-free survival (hazard ratio 4.68 and 5.6, respectively) and on breast cancer specific survival (hazard ratio 2.61) [8].