Planar polarity: A new player in both lung development and disease.

The clinical burden of both adult and neonatal lung disease worldwide is substantial; in the UK alone, respiratory disease kills one in four people. It is increasingly recognized that genes and pathways that regulate lung development, may be aberrantly activated in disease and/or reactivated as part of the lungs' intrinsic repair mechanisms. Investigating the genes and signaling pathways that regulate lung growth has led to significant insights into the pathogenesis of congenital and adult lung disease. Recently, the planar cell polarity (PCP) pathway has been shown to be required for normal lung development, and data suggests that this signaling pathway is also involved in the pathogenesis of some lung diseases. In this review, we summarize current evidence indicating that the PCP pathway is required for both lung development and disease.