FGF9 and cancer: Studies exploring the role of FGF ligands in cancer are mostly limited to adult cancer subtypes and include FGF2, the most commonly implicated FGF in cancer, FGF1 in ovarian, FGF4, FGF9 and FGF22 in lung, FGF5 in breast, FGF6, FGF19, and FGF21 in liver, FGF7 and FGF18 in gastric, and FGF8, FGF17, FGF19, and FGF23 in prostate cancer (reviewed in [72]).