Furthermore, use of the Mantel-Haenszel method (χ2=11.48; P<0.01) and adjusted Mantel-Haenszel method [OR, 4.29 (95% CI, 1.85–9.95)] indicate that HER2 expression is associated with patient survival rate and, therefore, is one of the important risk factors of mortality rate in breast cancer. The gene discussed is ERBB2; the disease is breast cancer.