As for the receptors of the FGF ligands, four distinct FGF receptors (FGFRs), FGFR1 (Flg), FGFR2 (K-sam), FGFR3, and FGFR4 exist, and if deregulated can function as oncogenes to drive specific cancer types including GC (17, 34–36). Here, FGFR4 is linked to cancer.