Based on our initial data demonstrating that trastuzumab can eliminate HER2+ CTCs57, the patient was enrolled in an open-label randomized Phase II trial of secondary adjuvant trastuzumab in early-stage breast cancer patients harboring HER2+ CTCs after the completion of adjuvant chemotherapy and radiotherapy42 and trastuzumab administration resulted in a clear decrease of the CTCs numbers lasting for 8 months. The gene discussed is ERBB2; the disease is breast cancer.