Matrix metalloproteinase-2 and -9 expression in sinonasal inverted papilloma.

STATEMENT OF PROBLEM

Inverted papilloma (IP) is a proliferative lesion of the epithelium lining the sinonasal tract, characterized by marked propensity for recurrence and association with carcinoma. To determine a putative role of matrix metalloproteinase-2 (MMP-2) and MMP-9 in the establishment of IP, their expression was studied in IP.

METHODS

Archived surgical specimens from 15 IPs were studied using immunohistochemistry and compared to 12 nasal polyps (NP), a model of chronic respiratory mucosal inflammation, and to 6 control nasal mucosa (CM) samples obtained from snorers during turbinectomy. Within IP, MMP-2 and -9 expression was compared between tumoral areas with hyperplastic epithelium and non tumoral areas with nonhyperplastic epithelium.

RESULTS

In IP, MMP-2 and MMP-9 epithelial expression was not different compared to CM and NP. MMP-9 expression in submucosal inflammatory cells was not different between IP and CM or NP. However, within IP, a significantly increased number of MMP-9 positive inflammatory cells in the lamina propria adjacent to the hyperplastic epithelium was observed compared to the lamina propria adjacent to nonhyperplastic epithelium.

CONCLUSION

Our findings suggest that MMP 9 expressing inflammatory cells may be involved in the pathophysiology of IP.