MDSCs promote cancer cell invasion by establishing an immune-tolerant and inflammatory environment through the downregulation of IFNγ, overexpression of inflammatory cytokines, and inducing leaky vasculature by expressing matrix metalloproteinase 9 (MMP9) and other remodelling factors to diminish the integrity of the extracellular matrix (ECM) and the basal membrane [62]. The gene discussed is MMP9; the disease is cancer.