Destruction of tumour parenchyma in basal cell carcinoma by tumour-associated neutral proteases: a histochemical study

Abstract

Proteolytic activity was demonstrated histochemically in frozen sections of basal cell carcinomas (BCCs). After incubation of tissue sections in 0.1 M phosphate buffer with 0.25 M NaCl the tumour epithelium was almost completely destroyed. The basal and squamous cell layers of the epidermis disintegrated to varying degrees, particularly where they were directly in contact with tumour epithelium. Serine and metalloprotease inhibitors diminished this tissue destruction. Iodoacetate enhanced tumour destruction, urea and potassium thiocyanate even more so. The high proteolytic activity of BCC demonstrated in this study may be an important factor in the proliferative, invasive and destructive behaviour of this tumour.