简介：Thematrixmetalloproteinases(MMPs)areafamilyofzine-dependentendopeptidasesthatplayakeyroleinbothnormalandpathologicalprocessesinvolvingtissueremodelingevents.Theexpressionoftheseproteolyticenzymesishighlyregulatedbyabalancebetweenextracellularmatrix(ECM)depositionanditsdegradation,andiscontrolledbygrowthfactors,cytokines,hormones,aswellasinteractionswiththeECMmacromolecules.Furthermore,theactivityoftheMMPsisregulatedbytheirnaturalendogenousinhibitors,whicharemembersofthetissueinhibitorofmetalloproteinases(TIMP)family.Inthenormalmammarygland,MMPsareexpressedduringductaldevelopment,lobulo-alveolardevelopmentinpregnancyandinvolutionafterlactation.Underpathologicalconditions,suchastumorigenesis,thedysregulatedexpressionofMMPsplayaroleintumorinitiation,progressionandmalignantconversionaswellasfacilitatinginvasionandmetastasisofmalignantcellsthroughdegradationoftheECMandbasementmembranes.