ERBB2 and breast cancer: HER‐2 ECD is a prognosis factor that is valuable in evaluating the neoadjuvant treatment efficiency.20 HER‐2 ECD also appears to be a helpful surveillance biomarker for the early diagnosis of relapses and to predict the fate of metastases.15 Our present paper indicated that HER‐2 ECD had a high specificity to distinguish breast cancer patients from benign (5% increased HER‐2 ECD) and healthy controls (4% increased HER‐2 ECD).