Characterization of Cyclooxygenase in Laryngeal Papilloma by Molecular Techniques

AbstractObjectives: Demonstrate the induction of cyclooxygenase‐2 (COX‐2) in laryngeal papilloma. Discuss the possible causal role of COX‐2 in papilloma formation. Consider the potential for treatment of papilloma using selective COX‐2 inhibitors. Study Design: Molecular biological analysis of COX‐1 and COX‐2 in laryngeal papilloma. Methods: Tissue samples from five patients with recurrent respiratory papillomatosis (RRP) were analyzed by in situ hybridization, immunohistochemical staining, and reverse transcription polymerase chain reaction (RTPCR) techniques. Results: In situ hybridization to COX‐2 mRNA showed strong autoradiographic signal surrounding fibrovascular cores. COX‐1 autoradiographic signal was low intensity or nondetectable. Normal buccal mucosa biopsies showed low‐density or nondetectable autoradiographic signal for both COX‐1 and COX‐2 mRNAs. In situ hybridization results were corroborated by RT‐PCR studies. Levels of COX‐2 mRNA were 13‐fold more than those in normal mucosa. Immunohistochemical staining for COX‐1 and COX‐2 showed a similar pattern to that seen with in situ hybridization in both normal and papilloma tissues. Conclusions: There is an elevation of COX‐2 expression in papilloma tissues. This may represent a causal role of COX‐2 in the formation and proliferation of laryngeal papilloma. There may also be a role for selective COX‐2 inhibition for the treatment of RRP.