Down-regulation of gelsolin may play a role in the progression of inverted papilloma through an antiapoptotic mechanism.

BACKGROUND

Gelsolin is an actin-binding protein with multiple cellular functions including apoptosis and is reported to be down-regulated in various cancers and premalignant lesions. The objective of this study was to identify gelsolin and caspase-3 expression in inverted papilloma (IP) and investigate the role of gelsolin in the progression of IP related to apoptosis.

METHODS

Specimens from 30 patients with nondysplastic IP were retrieved. The percentage of surface epithelium covered with squamous metaplastic epithelium was assessed. Immunohistochemically demonstrated gelsolin and caspase-3 expression were compared between IP and adjacent control mucosa. We analyzed the correlations among gelsolin expression, caspase-3 expression, and the degree of squamous metaplasia in IP.

RESULTS

The degree of squamous metaplasia of surface epithelium was inversely correlated with gelsolin (r = -0.610; p < 0.001) and caspase-3 expression (r = -0.433; p = 0.017). Gelsolin expression in IP was significantly lower than that in the control when >50% of surface epithelium showed squamous metaplasia (p = 0.015). Caspase-3 also showed diminished expression when >50% of surface epithelium had undergone squamous metaplasia (p = 0.035). Gelsolin and caspase-3 expression showed no significant differences when the degree of squamous metaplasia was ≤50%. Gelsolin and caspase-3 expression levels in IP had a positive relationship (r = 0.557; p = 0.001).

CONCLUSION

Progression of IP may be related to an insidious decrease in caspase-3-mediated apoptosis, and down-regulated gelsolin expression may be correlated with the decrease in apoptosis, especially in more highly progressed IP in which >50% of surface epithelium has undergone squamous metaplasia.