Since MMPi was equally effective as proteinase K in blocking EV-mediated TGF-β signaling, MMP9 (or another MMP) must play an important role in facilitating TGF-β signaling by tumor cell-derived EVs, most logically, by activating the predominant latent TGF-β form (Fig. 4I). The gene discussed is TGFB1; the disease is neoplasm.