A common theme in organogenesis of epithelial tubes, for the lung, liver, or kidney. The later morphogenesis of these branched epithelia dictates the final form and function of the mature tissue. Epithelial branching requires the specification of branch cells, the out-folding process itself, and, frequently, patterned morphogenesis produces branches of specific shape and orientation.  epithelial cell; Hatton-Ellis E et al 2007 Proc Natl Acad Sci USA 104:169.