Cyclooxygenase-1 is upregulated in squamous cell carcinoma of the head and neck

BM Erovic MD^a, S Kandutsch MD^b, M Woegerbauer MS^f, F Frommlet PhD^c, E Selzer MD^d, GV Kornek MD^e, C Neuchrist MD^a, MC Grasl MD^a, D Thurnher MD^a

^aDepartment of Otorhinolaryngology, Head and Neck Surgery, Austria, ^bClinical Pathology, ^cMedical Statistics, ^dRadiotherapy and Biology, ^eInternal Medicine, Division of Oncology; University of Vienna Medical School, Austria, ^fDepartment of Research and Development, Birkmayer Laboratories

Aim: Cyclooxygenase-1 is reported to be constitutively expressed as a housekeeping gene in most tissues. However, there are only a few publications demonstrating that this enzyme might be overexpressed in squamous cell carcinoma compared to normal tissue. Therefore the aim of this study was to investigate whether cyclooxygenase-1 is overexpressed in tumor specimens of the head and neck compared to normal oral mucosa. Material & Methods: Immunohistochemistry of cyclooxygenase-1 was performed in 43 paraffin-embedded tumor biopsies and 12 samples of normal oral mucosa. Using 5 fresh frozen tumor and oral mucosa samples, respectively cyclooxygenase-1 mRNA was quantified by real-time RT-PCR. Protein expression of Cyclooxygenase-1 was determined using western blotting. Results: Expression of Cyclooxygenase-1 mRNA protein was significantly upregulated in all tumor biopsies compared to normal oral mucosa (p < 0.0001). Conclusion: We could show for the first time that cyclooxygenase-1 is overexpressed in head and neck squamous cell carcinoma. This result could explain that non-selective cyclooxygenase inhibitors act almost as cytotoxic on tumor cells of the head and neck as the “older” non-selective cyclooxygenase inhibitors.

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in oral session 993 (Molecular pathology - Part II).