The numbers and strengths of those interactions in each kidney group were summarized (Figure 6b); the numbers of cell-to-cell interactions are higher in Pkd1 HET-7 and Pkd1 HOMO-14 kidneys (1601 and 1597, respectively) than in the other four kidney groups, whereas the strengths of those interactions were gradually increased in Pkd1 HOMO kidneys from day 7 to day 21, which might have been mediated by an increase in the expressions of either ligands, receptors or both in Pkd1 HOMO kidneys during cyst progression. Here, PKD1 is linked to cyst.