The Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) is expressed in 
multiple human malignancies and has potent effects on cell growth. It has been 
detected in exosomes and shown to inhibit immune function. Exosomes are small 
secreted cellular vesicles that contain proteins, mRNAs, and microRNAs (miRNAs). 
When produced by malignant cells, they can promote angiogenesis, cell 
proliferation, tumor-cell invasion, and immune evasion. In this study, exosomes 
released from nasopharyngeal carcinoma (NPC) cells harboring latent EBV were 
shown to contain LMP1, signal transduction molecules, and virus-encoded miRNAs. 
Exposure to these NPC exosomes activated the ERK and AKT signaling pathways in 
the recipient cells. Interestingly, NPC exosomes also contained viral miRNAs, 
several of which were enriched in comparison with their intracellular levels. 
LMP1 induces expression of the EGF receptor in an EBV-negative epithelial cell 
line, and exosomes produced by these cells also contain high levels of EGF 
receptor in exosomes. These findings suggest that the effects of EBV and LMP1 on 
cellular expression also modulate exosome content and properties. The exosomes 
may manipulate the tumor microenvironment to influence the growth of neighboring 
cells through the intercellular transfer of LMP1, signaling molecules, and viral 
miRNAs.