<p>Epstein-Barr virus was the first human virus to be directly implicated in cancer development. Most adults are infected with the Epstein-Barr virus, but relatively few will ever develop the cancers of which this virus is a contributory or necessary cause. Other factors beyond infection with the virus are needed to lead to the development of cancer. Environmental factors including some dietary factors are thought to render precancerous epithelial cells sensitive to Epstein-Barr virus infection, which then triggers malignancy.</p><p>Epstein-Barr virus is a DNA virus of the herpes family. It is now known that Epstein-Barr virus infects >90% of the worlds adults population. Upon infection, the individual remains a lifelong carrier of the virus. It is transmitted by salivary contact. It primarily infects B lymphocytes (white blood cells that produce antibodies), though it can also infect epithelial cells. Infection usually occurs in childhood and does not usually produce symptoms, but in adults it can cause infectious mononucleosis or glandular fever. It is particularly associated with undifferentiated nasopharyngeal carcinoma, the most prevalent type.</p><p>In nasopharyngeal carcinoma, all of the tumor cells carry viral DNA in a monoclonal form. This means that Epstein-Barr virus infection must have occurred quite early in the cancer process, before rapid growth. It is not normally possible to detect Epstein-Barr virus infection in non-cancerous nasopharyngeal cells.</p><p> </p><p>Janey Mulkerin</p>
