The regulation of cell polarity in the progression of lung cancer.

Lung cancer is the most frequent malignant disease, since it has often metastasized to distant organs by the time of diagnosis. Epithelial-mesenchymal transition (EMT) is an important process during the progression of lung cancer. Epithelial cells lose the polarity, which contributes to uncontrolled invasion and metastasis of cancer cells. Cell polarity establishment and maintenance depends upon the three complex proteins which are par, crumbs and scribble complexes, of which are reported as tumor suppressors. The cell polarity proteins could interact with cell-cell contact and cell-extracellular matrix contact and cell-intrinsic signaling. These interactions are proved to be involved in lung cancer metastasis. However, our understanding of the mechanisms by which this occurs is poor. In this review, we will discuss the regulatory network of cell polarity in the lung cancer, especially on EMT.