Presence of high levels of MT1-MMP protein in fibroblastic cells of human invasive carcinomas

Matrix metalloproteinase 2 (MMP2) activity is associated with the aggressiv eness of human cancers. Therefore, the mechanisms regulating its activation are of great interest for a better understanding of malignant invasive pro cesses. MT1-MMP, a membrane-bound MMP, is involved in the conversion of the latent form of MMP2 to the active one. In the present study, we have raise d 3 monoclonal antibodies (Mabs) directed against 3 different epitopes of h uman MT1-MMP, which we used to investigate the expression and cellular loca lization of MT1-MMP protein in human carcinomas. MT1-MMP protein was presen t in all invasive carcinomas tested, and it was almost exclusively located to the stromal cells and not to cancer cells as previously reported, sugges ting that MMP2 activation might be a peri-fibroblastic event. (C) 1999 Wile y-Liss, Inc.