While a role for FGFR4 has been previously shown [108,109], implicating the metabolic hormones FGF19, FGF23 and KLOTHO in cancer is equally intriguing; the emerging question being if dysregulation of these genes may be a direct cause of carcinogenesis or more generally a symptom of metabolic health, which in itself predisposes to cancer at a significantly younger age? This evidence concerns the gene FGF23 and cancer.