FGFR3 and neoplasm: Moreover, both BPV-E4- and BPV-E1^E4-mediated nucleofection of equine ACFCs brought about the upregulation of FGFR3 and FGF12 (fibroblast growth factor receptor 3 and fibroblast growth factor 12), which are known as factors promoting tumor growth and metastasis [51].