Epstein-Barr virus (EBV) is a type of virus that infects many people around the world. It is related to viruses that cause cold sores and chickenpox. Infection with this virus usually occurs in childhood as a throat infection, but can occur in adolescence or adulthood. In adolescence it causes "glandular fever."
What makes EBV special is that it has a unique set of genes that causes a growth activation of the cells that it infects. EBV mainly infects B-cells (a type of white blood cell). While most of the time the infection causes little damage, sometimes the growth activating genes may cause the infected B-cells to turn into cancers in certain people.
EBV and Lymphoma Cancers
The most common cancers caused by EBV are lymphomas. At least 3 types of lymphoma have a definite link to EBV infection. Another cancer that can be caused by EBV infection is cancer of the nasopharynx (the upper part of the throat behind the nose).
Post-Transplant Lymphoma and AIDS-Associated Lymphoma
EBV is strongly related to developing lymphoma after organ transplants. After any sort of organ transplantation, those receiving the transplant have to be given drugs that prevent an immune response to foreign material (that will cause a rejection of the transplant). These drugs unfortunately can weaken the immune system and make the body susceptible to different viral infections, including EBV. During AIDS too, there is a loss of immune control over viral infections in the body. Viruses like EBV can cause abnormal growth of infected B-cells and turn them into cancer cells of lymphoma.
Burkitt's Lymphoma and Malaria
In many parts of Africa, EBV is also strongly linked to a second lymphoma - the endemic type of Burkitt’s lymphoma. This lymphoma is the most common cancer of childhood in many parts of Africa. EBV causes specific genetic changes that turn B-cells into cancer. Repeated malarial infection helps EBV to cause lymphomas by activating B-cells and making them more prone to abnormal change by EBV.
Hodgkin's lymphoma is a third lymphoma that is linked to EBV. In western countries, nearly 40% of individuals with Hodgkin's are also infected with EBV. The infection rate may be even higher in many other parts of the world. The exact mechanism by which EBV may cause Hodgkin's lymphoma is not well understood, but it is becoming very evident that EBV has an important role to play in the development of this lymphoma.