INCREASED ACTIVITY OF CATHEPSIN-B IN FIBROBLASTS ISOLATED FROM PRIMARY MELANOMA IN COMPARISON TO FIBROBLASTS FROM NORMAL SKIN

We determined activity of cathepsin B in early-passage fibroblasts iso lated from primary melanoma and in fibroblasts from normal skin. Our r esults show an up to 5-fold increase in activity of cathepsin B in the tumor-derived fibroblasts in comparison to the fibroblasts from norma l skin. We conclude that fibroblasts isolated from melanoma tissue are altered with regard to their specific activity of cathepsin B and pre serve this elevated activity in early-passage cell culture. The data s upport the idea that stromal cells are not passive elements of the per itumoral environment but actively participate in the production of pro teolytic enzymes.