In experimental cancer cell systems, knockdown of occludin has been linked to decreased epithelial cell-cell adhesion and reduced susceptibility to apoptosis induction in human keratinocytes [8], disoriented epithelial cell migration in Madin-Darby canine kidney (MDCK) cells [9], increased apoptosis and reduced invasion ability of lung cancer cell lines [10], epithelial-mesenchymal transition (EMT) in epithelial cell cultures [11] and increased cell migration and invasion in colon cancer cells [12]. Here, OCLN is linked to lung cancer.