Immortalization of epithelial cells.

The methodologies for isolating cell lines have become very powerful, particularly in terms of retaining differentiated features of the parent cells. Cell lines can be developed from primary or early passage cells as well as from transgenic animals that carry an immortalizing gene. Cell lines from epithelia have been selected for their polar orientation, tight junction formation, and expression of differentiated markers or functions. These cell lines provide useful models for studying cell biology of specific tissues, tumorigenicity, genetic abnormalities, or to help screen for effective methods of gene therapy.