During these process, TNF-α upregulated the expression of vascular cell adhesion molecule-1 (VCAM-1) and amino acid transporter type 2 (ASCT-2) on vascular endothelium and upregulated the expression of very late activation antigen 4 (VLA-4) and syncytin-1 on cancer cells, respectively [87, 88], which played critical roles in promoting oral cancer–endothelial cell fusion. Here, ERVW-1 is linked to lip and oral cavity carcinoma.