Relationship between Epstein-Barr virus infection and nasopharyngeal carcinoma pathogenesis.

Nasopharyngeal carcinoma (NPC) is one of the common cancers among Chinese living in South China, Taiwan, Singapore, and several other countries or regions in distinct areas. The etiological factors have not been clearly identified yet. So far, no major gene related with hereditary factor has been identified in NPC carcinogenesis; however, some environmental factors, such as consumption of salted fish and long-term exposure to sulfuric-acid vapor, have been tentatively linked to NPC induction, while research has proposed that there is a close association between Epstein-Barr virus (EBV) and NPC pathogenesis. To investigate the relationship between NPC and EBV, we have established ten NPC cell lines. After extensive investigation, we conclude that EBV may establish an infection only in nasopharyngeal neoplastic cells, not in metaplastic epithelial cells, through the IgA receptor (secretory component protein)-mediated endocytosis. Our observations indicate that EBV plays an important role in enhancement of NPC progression, but is involved in neither the initiation nor the promotion of NPC pathogenesis.