Simultaneous expression of cyclooxygenase-2 and microsomal prostaglandin E synthase in squamous cell carcinoma of the larynx

Abstract

Conclusion. In laryngeal cancer, arachidonic acid may be metabolized to PGE₂ via the cooperative actions of COX-2 and mPGES, which are induced in response to various stimuli. The COX-2-mPGES-PGE₂ system may induce differentiation of cancer cells and prevent metastasis, thus improving the survival rate. Objective. To examine the expression of COX-1, COX-2, and two downstream enzymes – microsomal PGE synthase (mPGES) and PGD synthase (PGDS) – using immunohistochemistry in human laryngeal squamous cell carcinoma (SCC). Patients and methods. Patients with laryngeal carcinoma were referred to the Department of Otolaryngology for treatment. Formalin-fixed, paraffin-embedded laryngeal carcinoma specimens were obtained from 24 patients. Immunohistochemical expression of COX-1, COX-2, mPGES, LPGDS, and HPGDS was investigated in 24 laryngeal carcinoma samples. Results. Among the carcinomas, cytoplasmic immunoreactivity for COX-2 was found in tumor cells in 18 of 24 cases (72%) and that for mPGES in tumor cells in 23 of 24 cases (92%). The localization of mPGES was very similar to that of COX-2. COX-2 in well-differentiated SCCs was higher than in poorly/moderately differentiated SCCs. In terms of lymph node metastasis, there was a significant difference in COX-2 expression.

• Prostaglandin
• cyclooxygenase
• PGE synthase
• laryngeal cancer