Expression of aspartic proteinase in squamous cell carcinoma of the floor of the mouth.

This is the authors' abstract. We don't add key points for this paper.

Cathepsin D and E are the main aspartic proteinases, suggested to be involved in the invasion and progression of cancer cells. We immunohistochemically studied the localization of cathepsins in oral carcinoma. Specimens of SCC of the oral floor, obtained from 18 patients, were prepared. Part of the serial paraffin sections were stained with hematoxylin-eosin and classified according to Anneroth's classification. Immunohistochemical staining was performed by the labeled streptavidin-biotin method, using affinity-purified polyclonal antibodies against cathepsin D and E. The expression of cathepsin D was observed in the cancer cells and was significantly increased in the T 4 category and in clinical stage III and IV. No significant difference was observed in the expression of cathepsins among the malignancy groups classified by Anneroth's method; medium and high malignancy groups were associated with shorter survival. The expression of cathepsin E in cancer cells was very low, and there was no correlation with any clinical or histopathological factor.