To enhance the penetration of the drug in PCa spheroids and thus in tumor tissues, a conjugate containing a matrix metalloproteinase 2 (MMP-2)-responsive N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer linked to a tumor-homing cyclic peptide iRGD has been recently developed [102]. Here, MMP2 is linked to posterior cortical atrophy.