Lymphoma is the fifth most common cancer in the United States and represents over forty subtypes of cancers arising within the lymphatic system. The two most prevalent types are Hodgkin’s and non-Hodgkin’s lymphomas. Of the 63,700 estimated new cases of lymphoma in 2005, non-Hodgkin’s lymphoma accounts for about 88 percent of those cases. The incidence of non-Hodgkin’s has increased, nearly doubling over the past 30 years. Researchers speculate that the increase may be due in part to environmental agents triggering genetic factors which initiate malignancies. Hodgkin’s lymphoma, with 7,000 new cases predicted in 2005, is a less prevalent disease. The cause of most lymphomas is unknown, but a compromised immune system and exposure to carcinogens, bacteria and viruses may play a role. The incidence of lymphoma is increased in patients infected with Epstein-Barr virus (which causes mononucleosis) or HIV.

Lymphomas result when cells in the immune system multiply uncontrollably. The immune system is maintained by lymphocytes; T-cells and B-cells, each playing specific roles in fighting disease…