Collagenolytic activity by malignant tumours.

Five carcinomas and 5 sarcomas were investigated in relation to their production of neutral proteases capable of digesting polymeric collagen. The carcinomas were far more active than the sarcomas but all the malignant tumours produced enzymes which were capable of causing collagenolysis in vitro. collagenolytic enzymes were recovered from extracts of neoplastic cells from long-term culture, from the media in which these cells were cultured, from the media of mixed cell cultures (neoplastic, stromal and inflammatory cells from minced tumours), and from normal fibroblasts cultures. In contrast to the cultures of non-neoplastic fibroblasts, the tumour cells produced active enzymes, since limited proteolysis with trypsin or treatment with p-aminophenyl-mercuric acetate (APMA) caused no increase in enzyme activity. These tumours possess collagenolytic ability in vitro which may be partly responsible for their invasive nature in vivo.