Fibroblast growth factor (FGF) 19 in the exosomes of NPC mesenchymal stem cells can encourage occurrence, proliferation and metastasis of the tumor and the mechanism involves activating the FGF19-FGFR4-dependent ERK signal cascade and regulating EMT to stimulate the growth of NPC 60. The gene discussed is FGFR4; the disease is nasopharyngeal carcinoma.