MMP9 and cancer: Moreover, downregulation of miR-21-5p has been found to inhibit cancer cell proliferation and induce apoptosis by suppressing the ERK and PI3K/Akt signaling pathways, elevating full-length E-cadherin expression, reducing the expression of the mesenchymal marker vimentin as well as MMP-2 and MMP-9, and acting as an extracellular inducer of MMPs [67].