Expression of Metalloproteinases MMP-2 and MMP-9 in Antrochoanal Polyps

BACKGROUND: Matrix metalloproteinase (MMP) 2 and MMP-9 are known to cleave specifically type 4 collagen, which is a major structural component of basement membrane. This is an early step of inflammation. Because of this property they have been studied in chronic sinonasal disorders. The aim of this study was to determine the MMP-2 and MMP-9 expressions in an antrochoanal polyp (ACP). METHODS: We examined tissue samples from 10 ACPs, 10 diffuse nasal polyps, and 10 control nasal mucosa (CM) by immunohistochemistry for MMP-2 and MMP-9 expression. RESULTS: Most of epithelial and endothelial cells showed positive immunostaining for MMP-2 and MMP-9 in all tissue samples. MMP-2 staining of inflammatory cells showed no difference among the groups (p > 0.05). On the other hand, MMP-9+ inflammatory cells were found to be significantly increased in ACP and diffuse nasal polyps when compared with CM (p < 0.05). CONCLUSION: MMP-9-expressing inflammatory cells could play a role in the pathophysiology of ACP as well as nasal polyps.