It was found that PCa-derived exosomes do express MMP-9 and MMP-14 by stimulating ERK1/2 phosphorylation, inhibiting the apoptosis of PCa cells, enhancing their migration rate, and preparing for invasion and metastasis (Wang et al., 2009; Vlaeminck-Guillem, 2018). Here, MMP9 is linked to posterior cortical atrophy.