Glial cell-derived neurotrophic factor expression in normal human lung and congenital cystic adenomatoid malformation.

Abstract Context.—It has been recently suggested that dysregulation of developmental factors and disruption of cell turnover could play a role in the pathogenesis of congenital cystic adenomatoid malformation of the lung (CCAM). The glial cell–derived neurotrophic factor (GDNF) is a growth factor involved in organogenesis, and the temporal pattern of GDNF expression suggests that this factor may play a role in lung development. Design.—We studied GDNF expression by immunohistochemistry in postnatally resected CCAM of the lung (n = 10), normal fetal lung (n = 5), and normal postnatal lung (n = 5). We also studied the association between GDNF expression and both cell proliferation and apoptosis. Results.—GDNF was expressed in both epithelial and endothelial compartments of normal fetal lung, whereas no expression was found in normal postnatal lung. In contrast, in CCAM tissue, there was strong GDNF immunostaining that was restricted to epithelial cells. The percentage of proliferating epithelial cells was h...