OCLN and neoplasm: The tumor cell spread along the vessels involucrates three processes: first, the dissolution of the extracellular matrix and its endothelial attachments (VE-cadherin, occludin) and second, the tumor adhesion to the endothelium, by the expression of integrins, neural cell adhesion molecule 1 (L1CAM), CXC chemokine receptors (CXCR), and Epithelial Growth Factor Receptor (EGFR) [55,66,67,68,69].