In addition to detecting serum biomarkers for disease diagnosis, overexpressed cell-surface receptor tyrosine kinases, such as human epidermal growth factor-2 (HER2) and epidermal growth factor receptor (EGFR), have been used as predictive biomarkers for patients with different solid tumors, including non-small cell lung cancer (NSCLC). The gene discussed is ERBB2; the disease is non-small cell lung carcinoma.