Coculturing of CAFs with prostate cancer PC-3 and DU 145 cells with the KLF5KR mutant released more Fgf9 than did the WT control at both the mRNA and protein levels (Figure 6, A and B), indicating that the signal from prostate cancer cells was essential for CAFs to release FGF9. Here, FGF9 is linked to Familial prostate cancer.