Objective: To assess the significance of cyclo-oxygenase 2 (COX-2) in laryngeal squamous cell carcinoma (LSCC). Study Design: An immunohistochemical study in which 39 patients with LSCC were included. Methods: Immunohistochemical staining of the paraffin-embedded tumour tissues was performed using isoform-specific COX-2 polyclonal antisera (Santa Cruz, Calif., USA). COX-2 results were compared with the clinical parameters of the patients. Results: COX-2 was detected in all tumour tissues. In the normal laryngeal tissue around the tumour area, which served as control, there was no COX-2 staining. There was no relationship between the COX-2 results and the location of the primary tumour, T stage and N stage, survival, recurrence or pulmonary metastases. Conclusion: The absence of a relation between COX-2 positivity and clinical parameters may suggest an involvement of COX-2 in laryngeal carcinogenesis. Since COX-2 positivity could be detected in all LSCC specimens studied, COX-2 could serve as a therapeutic target in LSCC. Copyright (C) 2004 S. Karger AG, Basel.