Therefore, in patients with MIBC HER2−, the high serum miR-19a levels may be due to the secretion from treatment-resistant tumor cells; whereas in patients with MIBC HER2+, the high serum miR-19a levels may be due to an effective Th1-mediated immune response and cells lysis/apoptosis of treatment-sensitive tumor cells (ADCC). The gene discussed is ERBB2; the disease is neoplasm.