Home > Research > Cancer chemoprevention Prevention, delay or reversal of the process of carcinogenesis through the administration of one or more chemical entities, either as individual drugs or as naturally occurring constituents of the diet. Multistage Process of Carcinogensis Chemopreventative Agents Is the primary cause of cancer mortality. Occurs by a complex multistep process (cell adhesion, invasion, proliferation, and vessel formation). Proteolytic enzyme degradation of the extracellular matrix (ECM) is a crucial step of tumor invasion and metastasis. Matrix metalloproteinases (MMPs) comprise a family of zinc-dependent endopeptidases that have been associated with tumor cell invasion and metastasis, owing to their capacity to degrade extracellular matrix components.