The incidence of
oral cancer is high in certain parts of the world including Southeast Asia. Smokeless tobacco and areca nut chewing is proposed as a possible factor.
Cyclooxygenase 2 (COX-2) receptors are present on neoplastic cells and are proposed to participate in initiation, transformation, progression and
metastasis of
cancer. In a prospective case-controlled study, 42 cases of
squamous cell carcinoma of the oral cavity, 13 cases of oral premalignant lesions, and oral mucosa from 32 normal subjects were evaluated for COX-2 gene expression using
reverse transcriptase polymerase chain reaction. The mean age of the patients with
oral cancer was 60.2 years. The majority of
cancer patients were males while the majority of controls were females. A significantly higher expression of COX-2 was found in
cancer patients compared to both normal controls (p=0.0001) and patients with premalignant lesions (0.015). The expression in premalignant lesions was higher compared to healthy subjects (p=0.05). COX-2 expression in
oral cancer was found to be independent of grade of
tumor and stage of disease. These results show up-regulation of the COX-2 gene in
oral cancer and precancer. This suggests a role for COX2 receptors in
oral cancer carcinogenesis, and provides the foundation for a large randomized trial to determine the role
COX2 inhibitors may play in prevention of oral
carcinogenesis.