PEG was modified on the surface of the vesicle through the MMP-responsive linker—GALGLPG (A short peptide), and when the vesicles reached tumor site, the GALGLPG peptide (Figure 1D) was cleaved by MMP-2 and then removed PEG to increase the endocytosis of the vesicles. This evidence concerns the gene MMP2 and neoplasm.