PTGS2 and nasopharyngeal carcinoma: For the 143 NPC cases, 137 case showed high expression of AP-2α, an average of 96.6% of the carcinoma cells stained positive with COX-2 protein; the percentage was significantly higher than that (85.9%) in the remaining 57 cases NPCs with 49 cases of high expression of AP-2α (P<0.001, Fig. 1E).