Developmental changes are a feature of ADPKD cells, with embryonic transcription factors such as PAX2 being persistently expressed in cystic epithelia (Stayner et al., 2006), and polarization defects such as the mis-localization of membrane bound proteins such as EGFR and the Na+K+ATPase, more closely resembling a fetal cellular distribution (Wilson et al., 1991). This evidence concerns the gene PAX2 and autosomal dominant polycystic kidney disease.