STAT3 and cystic kidney disease: While, during the progression of ADPKD, the cleaved PC1 tail could co-activate STAT1 that had been activated by IFN, STAT3 that had been activated by IL-6, EGF, HGF (hepatocyte growth factor) signaling, STAT6 that had been activated by IL4, IL-13 signaling to promote renal cyst growth and fibrosis [108].