ErbB receptor tyrosine kinases (EGF receptor or EGFR, ErbB2, ErbB3, and ErbB4) and their ligands play important roles in renal development, in renal electrolyte homeostasis and tubule repair following injury.[4], [5], [6], [7], [8], [9], [10] EGFR is normally sorted to basolateral membranes in mature tubular epithelial cells.[8] However, numerous primary PKD causing mutations alter EGFR polarity, leading to increased apical expression and activity.[11] Cystic epithelial cells from ADPKD patients are unusually susceptible to the proliferative stimulus of EGF. Here, EGF is linked to autosomal dominant polycystic kidney disease.