Motylewska E, et al. - Dysregulation of this fibroblast growth factor 19 (FGF19)/fibroblast growth factor receptor 4 (FGFR4)/βKlotho (βKL) signaling axis has been implicated in the pathogenesis of several cancers. In this current study, FGF19, FGFR4 and βKL concentrations were assessed among patients with thyroid cancer. Based on the findings, it was suggested that a disrupted FGF19/FGFR4/βKL signaling pathway could play a role in the development of thyroid cancers.