The expression of cathepsin D in nasopharyngeal carcinoma and its clinical significance

Abstract

Objective To evaluate the expression level of cathepsin D protein in nasopharyngeal carcinoma (NPC) and to determine its relationship with clinic pathological characters. Method Immunohistochemistry was performed to detect the expression of cathepsin D in 72 cases of primary NPC and 28 cases of normal nasopharyngal epithelial tissue ( NNET), and the correlation of its expression level with clinicopathologic features and clinical outcomes was evaluated. Results Significant down-regulation of cathepsin D was observed in NPC versus NNET(x2 = 13. 55, P ＜0. 01 ). In addition, cathepsin D down-regulation was significantly correlated with poor histological differentiation ( x2 =41.47, P ＜0. 01 ). Type Ⅰ and Ⅱ (well-moderately differentiated) NPC showed more intense immunoreactivity of cathepsin D compared with type Ⅲ (poorly differentiated) NPC. Cathepsin D up-regulation was significantly correlated with clinical stage, recurrence, and lymph node and distant metastasis (x2 = 13.43,22. 86,21.61,14. 32, P ＜0. 01 ).Tumors with cathepsin D up-regulation tended to have advanced clinical stage, frequent recurrences, and metastasis to lymph node and distant organ. Conclusion The expression of cathepsin D was closely related with the differentiation, clinical stage and pathological grade of NPC. Cathepsin D could be served as an effective differentiation marker for the histopathological grading of NPC and a possible therapy target. Key words: Cathepsin D/ME ; Nasopharyngeal neoplasms/ME/PA