Alterations in ultrastructure and c-met expression in a case of ocular epithelial dysplasia following topical mitomycin C treatment

Purpose: Topical mitomycin C (MMC) administration is reportedly effective i n treating ocular surface neoplasms such as squamous cell carcinoma. We tre ated a case of ocular epithelial dysplasia that had spread too diffusely to be completely removed. We examined the ultrastructure of and c-met (hepato cyte growth factor receptor) expression in dysplastic epithelial cells from this case to evaluate the efficacy of MMC treatment. Methods: Specimens of dysplastic epithelial tissue from the corneo-limbal r egion of a 62-year-old man were obtained before and after topical applicati on of MMC. Specimens were examined ultrastructurally and immunohistochemica lly with an antibody against human c-met. Results: Following topical application of MMC, the dysplastic epithelium ex hibited multilayered epithelial cells similar to those seen before treatmen t. However, ultrastructural examination showed tight interdigitation betwee n neighboring cells, with no intercellular spaces. Also, the marked immunor eactivity to c-mer in the dysplastic epithelial cells before MMC treatment was decreased after treatment. Conclusions: Ultrastructural observations indicated a restoration of epithe lial cellular differentiation following MMC application. The expression of c-mer protein was also reduced. Thus, topical MMC was effective in treating epithelial dysplasia of the ocular surface, with no recurrence 15 months p ost-therapy. (C) 2000 Japanese Ophthalmological Society.