FGFR2 and cyst: We focused on exploring the relationships between cyst cells and the other cell types, and we found that CDPC, PT, and the rest of the DCTs express Fgf9, which can bind to the Fgfr2 receptor in cyst cells; FGF9/FGFR2 interactions have been reported to induce cell proliferation (Chang et al., 2018).