MMP2 and neoplasm: Interestingly, these techniques showed several advantages over the conventional PROTAC approach, including (i) prolongation of the blood circulation time; (ii) higher tumor accumulation (3.9-fold) than their small molecule counterparts; (iii) the availability of several methods of activation (extracellular MMP-2, intracellular acidity, and reduction with glutathione) to release the active PROTACs.