Lymphoma Causes

The cause (or causes) of Hodgkin’s disease and non-Hodgkin’s lymphoma are unknown. Recent research, however, points to a number of possible risk factors, as well as to an increased risk of developing lymphoma in certain age groups. Some of the potential causes and risk factors are described here.

Hodgkin’s Disease Risks

Researchers worldwide have yet to establish a specific cause or dominant susceptibility factor for Hodgkin’s disease (HD). Recent findings from several studies and clinical trials, however, have highlighted a number of potential risk factors for developing HD, including:

Age: The likelihood of developing Hodgkin’s disease increases in young adults, particularly males in their mid-20s. Risk decreases in middle age, but then increases again from the age of fifty on.

Reduced immunity: Individuals with a lowered immune response, for whatever reason, are more likely to develop HD. For example, a link has been established with the increasing number of occurrences of acquired immune deficiency syndrome (AIDS) and the onset of HD.

Drugs: Immunosuppressive drugs, such as those used for the treatment of rheumatoid arthritis, or drugs administered routinely following an organ transplant, have been shown to increase the likelihood of developing the disease.

Infection: Individuals who have had glandular fever (infectious mononucleosis), an infection caused by the Epstein-Barr virus, may be at increased risk.

Exposure to environmental carcinogens: Pesticides, herbicides, viruses, bacteria and various other environmental factors may increase the risk.

Genetics: Some studies have revealed a genetic susceptibility in identical twins. The identical twin of an affected individual appears to have a greater risk than a random individual of developing HD in young adulthood. However, more research is required to link genetics with an increased susceptibility to developing Hodgkin’s disease.

Non-Hodgkin’s Lymphoma Risks

As with HD, the causes of non-Hodgkin’s lymphoma also remain unknown. Risk factors, however, are similar to those for Hodgkin’s disease. Possible factors include:

Age: Approximately ninety percent of non-Hodgkin’s lymphomas occur in adults, and the risk increases with age. The majority of people diagnosed with the disease are over the age of fifty. NHL is more common in men than in women. Research, however, has also shown that young children may have a slightly greater risk of developing NHL if they are born with immune system deficiencies.

Defective immune system: People with immune system defects or reduced immunity are at greater risk.

HIV/AIDS: Those affected with HIV or actually suffering from acquired immune deficiency syndrome (AIDS) have an increased susceptibility to developing NHL.

Infection and Burkitt’s lymphoma: A number of recent studies have revealed that infection with the Epstein-Barr virus (the virus responsible for mononucleosis) can significantly increase an individual’s chances of developing malignancies-in particular, Burkitt’s lymphoma. In addition, people who have had infections involving other viruses-like human T-lymphotropic virus type 1-may also be at a slightly increased risk.

Drugs: The connection with drugs applies particularly to individuals who have been treated with certain drugs for other cancers. A link has also been established between the use of dilantin, an anti-seizure drug, and the likelihood of developing non-Hodgkin’s lymphoma.

Chemotherapy: Studies have shown that individuals treated with certain chemotherapy drugs may be at increased risk of developing NHL, with the likelihood peaking at around five to ten years following the initial treatment.

Radiation: Radiotherapy treatment for other cancers may slightly increase the likelihood of developing NHL in later years. This risk also applies to individuals who have been exposed to nuclear radiation in the past.

Organ transplantation: Organ transplant recipients taking immunosuppressive drugs to counteract organ rejection are at particular risk.

Carcinogens, chemicals and environmental pollutants: Frequent exposure to certain petrochemicals, herbicides and insecticides such as weed-killers, fertilizers and insect-killing chemicals, has been linked with an increased likelihood of developing NHL. The use of solvents containing phenoxy acids, as well as occupational exposure to wood may also increase the likelihood of developing NHL.

Genetics: Recent studies suggest a possible genetic susceptibility to developing NHL in those born with a deficient or reduced immune system. More research, however, is required to explore the possibility of a hereditary link.

Resources

Cogliatti, S., Schmid, U. (2002). Who is WHO and what was REAL? Swiss Medical Weekly, 132, 607-617.

Phoenix5 Prostate Cancer Glossary. (2002). Lymphatic system. Retrieved April 14, 2003, from www.phoenix5.org/glossary/lymphatic_system.html.

Phoenix5 Prostate Cancer Glossary. (2002). Lymphocytes. Retrieved April 14, 2003, from www.phoenix5.org/glossary/lymphocytes.html.

Science at a Distance. (2000). Genotype and phenotype definition. Retrieved April 14, 2003, from www.brooklyn.cuny.edu/bc/ahp/BioInfo/GP/Definition.html.

Shaffer, A., Rosenwald, A.,