In this study, we applied laser capture microdissection and a proteomic approach to identify novel nasopharyngeal carcinoma (NPC) biomarkers. Proteins from pooled microdissected NPC and normal nasopharyngeal epithelial tissues (NNET) were separated by two-dimensional gel electrophoresis, and differential proteins were identified by mass spectrometry. Expression of the differential protein cathepsin D in the above two tissues as well as four NPC cell lines was determined by Western blotting. Next, siRNA was used to inhibit the expression of cath...