In addition, serum MMP3 activity was more valuable in diagnosis of NPC than its concentration (0.86 vs. 0.78, AUC), and MMP3 activity can improve the diagnosis of NPC by combining with EBV-infection biomarkers VCA-IgA and EA-IgA with a sensitivity of 91.5% and a specificity of 92.3%. The gene discussed is MMP3; the disease is infection.