This study will evaluate the ability of people of different ethnic backgrounds to develop immune responses against the Epstein-Barr virus (EBV). A common virus, EBV is present in 90 percent of healthy people and usually does not cause problems. Most people are infected in childhood, have no symptoms, and are unaware of their infection. People infected as adolescents or adults may develop infectious mononucleosis, which usually resolves completely. However, in immune suppressed people, like those who have had a transplant, EBV can cause fatal cancers. It can also cause certain cancers such as Burkitt's lymphoma, Hodgkin's lymphoma, and nasopharyngeal carcinoma in people who are not immune suppressed. Nasopharyngeal carcinoma is 100 times more common in people of Asian origin (particularly southern Chinese) compared with Caucasians. This difference may be the result of genetic, rather than environmental, factors. This study will examine whether the same proteins produced by EBV in the cancer cells react differently in people of different ethnic background in a way that could explain the differences in predisposition for this disease.