The area under the ROC curve (AUC) was 0.679 for CDC6 (p = 0.032), 0.808 for CDT1 (p = 0.000), 0.933 for MCM2 (p = 0.000) and 0.836 for CDC45 (p = 0.000), indicating that MCM2 and CDC45 were superior to CDC6 and CDT1, and could be used as useful tumor markers in diagnosing tongue SCC. The gene discussed is CDT1; the disease is tongue squamous cell carcinoma.