ELISA analysis showed that in the sera obtained from NPC patients, the CTSB concentration was 12.5 ± 3.5 mg/L (median, 12.4 mg/L), and the CTSD concentration was 15.7 ± 8.7 mg/L (median, 14.7 mg/L). The gene discussed is CTSB; the disease is nasopharyngeal carcinoma.