As an example, Felekkis et al. used, among other cell lines, primary tubular epithelial cells from a transgenic PKD rat model expressing a truncated polycystin-2 protein, to investigate p57/Cdk2 contribution to increased cell proliferation observed in ADPKD cyst lining epithelial cells [67]. Here, PKD2 is linked to autosomal dominant polycystic kidney disease.