STROMAL PROTEINASES AND TUMOR PROGRESSION

Recent observations, based on mRNA in situ hybridization studies, have shown that the main source of extracellular proteolytic activity in m ost human carcinomas comes from stromal cells of tumors and not from c ancer cells as was believed. These observations suggest that the role of extracellular proteinases during tumor progression may be more comp lex than previously proposed, and strengthen the concept that future a pproaches to cancer treatment should be directed at molecular mechanis ms specifically interfering with the tumor stroma.