Since the relationship between kidney fibrosis and mitogen-activated protein kinase (MAPK) pathway is well established27, we first evaluated p38 MAPK activation in TECs with HIF-2α activation, and found that phosphorylation of p38 MAPK was significantly associated with HIF-2α activation in TECs, suggesting that stimulation of p38 MAPK pathway by HIF-2α activation is, at least in part, could be related to the induction of renal fibrosis. Here, EPAS1 is linked to renal fibrosis.