Virology and immune mechanisms.

Epstein-Barr virus and hepatitis B virus are two agents which chronically infect man and have been associated with specific neoplasms. Such findings point the way to new methods of control and detection of human malignancies. Furthermore, immunosuppression is another major factor underlying the development of certain malignancies in human populations. It is clear that congenital immunodeficiency states as well as organ transplant recipients requiring iatrogenic immunosuppression and cancer patients requiring chemotherapy and/or x-irradiation are susceptible to particular malignancies at a higher rate than the normal population. Such findings also provide not only clues as to the mechanisms which control tumor development but argue for certain limitations to the extent of immunosuppressive therapy utilized for treatment of cancer.