12 patients who, after completing the entire complex of special treatment for breast cancer, retained BIRC5 mRNA- and HER2-neu mRNA-positive CTCs, for the eradication of the latter, 4 more weekly courses of monochemotherapy with gemcitabine in the mode of 800–1000 mg/m2 intravenously were carried out. The gene discussed is ERBB2; the disease is breast cancer.