Background: Many evidences showed that cyclooxygenase-2 (COX-2), an enzyme that catalyzes the synthesis of prostaglandins, has an important role in carcinogenesis. It has been observed in experimental models that selective COX-2 inhibitors suppress the formation of tumors including tongue carcinoma. The aim of this study was to investigate the immunohistochemical expression of COX-2 in oral squamous cell carcinoma (OSCC) compared to normal oral mucosa and oral dysplasia.
Materials and methods: A total of 60 paraffined blocks (20 cases of OSCC, 20 cases of oral epithelial dysplasia and 20 cases of normal oral mucosa were included in this study and immunohistochemical staining was done for COX-2 expression. From each sample, 5 high power fields were assessed to determine the percentage of stained cells and staining intensity. Immunoreactivity was obtained by multiplying the above two cases. Data were analyzed with using the Kruskal-Wallis test ANOVA, Mann-Whitney test and least significant difference and P<0.05 was declared as significant.
Results: High level of COX-2 expression was found in OSCC and dysplasia compared to normal mucosa. Furthermore, a positive correlation was found between COX-2 expression and severity of dysplasia. However, no significant difference between low grade and high grade tumors was found.
Conclusion: The result of the present study supports from the role of COX-2 in carcinogenesis and progression of premalignant lesion to malignancy.