Almost 30 years ago, it was observed that renal-cyst lining cells of PKD patients aberrantly expressed both the mitogenic hepatocyte growth factor and its receptor tyrosine kinase Met (Horie et al., 1994), while further mechanistic studies confirmed hyperactivation of Met signalling in Pkd1 models, pharmacological inhibition of which rescued disease phenotypes (Qin et al., 2010). This evidence concerns the gene PKD1 and cyst.