Increased gelatinase-A and gelatinase-B activities in malignant vs. benign breast tumors.

Matrix metalloproteinases (MMP) types 2 and 9 (also known as gelatinase A and B) are thought to be causally involved in cancer invasion and metastasis. In normal as well as in malignant tissue, both these MMPs occur in multiple forms such as inactive precursors, active enzymes and enzyme-inhibitor complexes. Using newly developed quantitative activity assays, the levels of active MMP-2, total (active and activatable) MMP-2 and total MMP-9 were found to be significantly higher in breast carcinomas than in fibroadenomas. In addition, active MMP-2 and MMP-9 were detected more frequently in malignant than in benign breast carcinoma. These new quantitative activity assays are likely to be of use in studying the mechanism of action of both MMP-2 and -9, assessing their potential prognostic value in different cancers and in the design of MMP inhibitors for preventing cancer metastasis. Copyright 2000 Wiley-Liss, Inc.