Expression of cathepsin L in nasopharyngeal carcinoma and its clinical significance

Xu X., Yuan G., Liu W., Zhang Y., Chen W.

Aim: To study the expression of cathepsin L in nasopharyngeal carcinoma (NPC), and analyze its relationship with clinicopathologic factors. Methods: The expression of cathepsin L was determined immunohistochemically in NPC, adjacent normal nasopharyngeal tissues and metastatic cervical lymph nodes. The correlation between its protein expression and clinicopathologic parameters as well as with long term follow-up data in NPC was analyzed. Results: The protein of cathepsin L was overexpressed in 47% primary tumor tissues, and in 89% metastatic cervical lymph node samples. Overexpression of cathepsin L was found to correlate with lymph node metastasis (P = 0.04) and distant metastasis (P = 0.01), and marginally with clinical stage and T classification, but not with patient age, gender and histological classification of tumor. Patients with overexpression of cathepsin L in tumor tissue had worse 5-year survival than those without such expression pattern (P = 0.033). Multivariate survival analysis showed that cathepsin L protein expression level had a marginal significant correlation with prognosis of NPC. Conclusion: Cathepsin L is a potential biomarker for prognosis of NPC and contributes to NPC metastasis.