A previous study demonstrated a requirement of Jnk for hepatic cyst formation in models of mitochondrial redox stress-induced cholangiocarcinoma [78] However, this role of JNK to promote cystogenesis appears to be dependent on physiological context because Jnk deletion alone was sufficient to cause hepatic cyst formation in another study of aged mice [79–81] JNK signaling may have tissue-specific roles in ADPKD that will be important to evaluate for therapeutic development. The gene discussed is MAPK8; the disease is cholangiocarcinoma.