Epstein-Barr virus latent membrane protein 1 (LMP1) is considered to be the major EBV oncoprotein. LMP1 is exclusively expressed in most NPC and is a potential target for biotherapy. LMP1-positive NPCs are reported to be more progressive than LMP1-negative NPCs and show an increasing tendency of lymph node metastasis. Structurally, LMP1 is an integral membrane protein consisting of a short cytoplasmic N-terminus of 20 amino acids, a transmembrane domain with 6 membrane-spanning segments that anchor LMP1 in a patchy distribution along the plasma membrane, and a long cytoplasmic C-terminus of 200 amino acids.