It is a determinant factor in the organotropism observed in cancer dissemination.215 A compromised BBB integrity, frequently associated with the upregulation of specific genes, plays a pivotal role in this process.216,217 For instance, the proteolytic action of cathepsin S, mediated by its interaction with the adhesion molecule JAM-B, can induce BBB leakage. Here, CTSS is linked to cancer.