 In standard cells, loss or disruption of occludin and other tight junction proteins leads to initiation of apoptosis through extrinsic pathways.Studies involving high levels of expression of occludin in cancer cells have shown that occludin mitigates several important cancer proliferation properties.The presence of occludin decreased cellular invasiveness and motility, enhanced cellular sensitivity to apoptogenic factors and lowered tumorigenesis and metastasis of the cancer cells.