Thirty seven out of eighty three (45%) tested CTCs-enriched blood fractions (further referred to as CTCs-EBF) were positive for general breast cancer markers MGB1 and HER2, and overall 19/46 (41%) preamplified samples were CTCs-positive (expressing MGB1 and/or HER2 and at least one epithelial or mesenchymal marker; Figure 1). The gene discussed is ERBB2; the disease is breast cancer.