EXPRESSION OF CATHEPSIN-D AND CATHEPSIN-B IN INVASION AND METASTASIS OF SQUAMOUS-CELL CARCINOMA

To determine the involvement of proteinases with hydrolytic activity t owards extracellular matrix and basement membrane, in invasion and met astasis of tumour cells, the expression of cathepsin D, an aspartic pr oteinase, and cathepsin B, a cysteine proteinase, was studied, Formali n-fixed paraffin-embedded specimens from 13 patients who had squamous cell carcinomas (SCC) with local recurrence, skin and/or lymph node me tastasis were examined, Cathepsin D stained intensely as a granular pa ttern (mature enzyme) in tumour cells of 69% of primary lesions and al l the secondary lesions of the patients with SCC. Cathepsin B stained more intensely in SCC cells of all of the primary and secondary lesion s than in normal epidermis: staining patterns were almost diffuse (pro cathepsin B), Granular and diffuse patterns (mature enzyme of cathepsi n D and procathepsin B, respectively) appeared in the outer and inner parts of tumour islands, respectively. The presence of the active matu re form of cathepsin D and procathepsin B in metastatic skin lesions o f SCC was confirmed by Western blotting analysis, The presence and loc alization of the active mature form of cathepsin D suggests that activ ated cathepsin D may be involved in the invasion and metastasis of SCC .