The MEK inhibitor PD184352 ameliorated PKD in pcy mice (Omori et al., 2006), but the MEK inhibitor UO126 had no effect on cystogenesis in Pkd1 knockout mice at doses sufficient to reduce phospho-ERK1/2 in cystic kidneys (Shibazaki et al., 2008). This evidence concerns the gene PKD1 and Renal cyst.