Prior to the establishment of bone metastases circulatingPCa cellsmust first enter the bone microenvironment by migrating across thesinusoidal wall.54 We have previously shownthat increased KLK14 activity drives PCa cell migration and colonizationof mineralized bone matrices.15 However,the specific contributions of the KLK activome (KLK2, KLK3, and KLK14)toward PCa cell migration are yet to be elucidated. Here, KLK2 is linked to posterior cortical atrophy.