MMP9 and cancer: KCs relase oxygen metabolites, cytotoxic cytokines, proteases, TNF-α and IL-1β to damage disseminated tumor cells (53, 85, 87, 88); KCs decrease cancer cells by promoting secreting GM-CSF and IFN-γ (53); KCs release growth factors (HGF, VEGF), cytokines (TNF-α, Il-1, IL-1β, IL-6 and IL-10), MMP9 and MMP14 to promote extravasation (49–51, 53) and outgrowth of metastases (53, 59–61)