Objective  To investigate the relationship between the expression of Yes associated protein (YAP), carbonic anhydrase Ⅸ protein and occurrence, development of nasopharyngeal carcinoma.

  Methods  Totally 80 tissue specimens of nasopharyngeal carcinoma were selected as nasopharyngeal carcinoma group, and 80 chronic inflammation tissues of nasopharyngeal mucosa were selected as control group. The expression of YAP protein and carbonic anhydrase IX protein in both groups were detected by immunohistochemistry, and the differences of YAP protein and carbonic anhydrase Ⅸ protein expression in nasopharyngeal carcinoma tissues with different age, gender and pathological characteristics were analyzed.

  Results  The positive expression rates of YAP protein and carbonic anhydrase Ⅸ protein in the nasopharyngeal carcinoma group were 76.25% and 58.75% respectively, which were significantly higher than 36.25% and 20.00% in the control group (P < 0.05).The positive expression rates of YAP protein in the non-differentiated and pathological phase Ⅲ to Ⅳ nasopharyngeal carcinoma tissues were significantly higher than those in the differentiated and pathological phase Ⅰ to Ⅱ nasopharyngeal carcinoma tissues (P < 0.05). There were no significant differences in the positive expression rate of carbonic anhydrase Ⅸ protein in nasopharyngeal carcinoma tissues of patients with different ages, gender, maximum diameter of focus, condition of lymph node metastasis, pathological differentiation and pathological phase (P>0.05).

  Conclusion  The expressions of YAP protein and carbonic anhydrase Ⅸ protein in nasopharyngeal carcinoma tissues are significantly up-regulated, and YAP protein expression is closely related to the occurrence and development of tumor.