Risk Factors for Hodgkin's Disease
Several cellular changes are associated with lymphoma; however, the reasons that these changes occur are unknown. Certain factors can increase the risk for Hodgkin's disease (HD). Some of these factors, such as age and genetics, are non-modifiable (i.e., beyond our control), and other factors, such as environment or lifestyle choices, are modifiable (i.e., able to be controlled or corrected).
All cancers, including lymphoma, begin as a mutation (change) in the genetic material—the DNA (deoxyribonucleic acid)—within certain cells. The external or internal causes of such change probably add up over a lifetime. DNA errors may occur in the form of translocations—damage produced when part of one chromosome becomes displaced and attached to another chromosome. Translocations disrupt the normal sequencing of the genes.
As a result, oncogenes (cancer-promoting genes) on the chromosomes may be switched on and tumor suppressors (cancer-preventing genes) may be switched off. These changes are common in cases of lymphoma. Physicians test for these translocations to help diagnose the type of lymphoma, determine a patient's prognosis (expected outcome), and detect cancer recurrence.
A number of factors may increase the risk for DNA damage within the body's lymphocytes (specialized white blood cells). Risk factors for Hodgkin's lymphoma include the following:
The rate of HD is high in two age groups: young adults (age 15–40) and older adults (age 55+).
In general, both Hodgkin's disease and non-Hodgkin's lymphoma affect men more often than women.
The risk of HD is somewhat higher in people who have been infected with viruses, such as Epstein-Barr virus (EBV). EBV infects the B-cells and causes an illness known as infectious mononucleosis (sometimes referred to as "mono"). In people who have mono, the infected B-cells are sought out and killed by the body's T-cells. But if the patient has a T-cell shortage, the EBV-infected B-cells build up within the bloodstream and increase the risk for genetic mutations that can cause lymphoma. It is important to note that there is no evidence of EBV infection in many HD patients, so its role in development of the disease remains uncertain.
Specific medical conditions may increase the risk for Hodgkin's disease and non-Hodgkin's lymphoma. HD and NHL are more common among patients who have a weakened immune system, such as those with:
- Acquired immunodeficiency syndrome (AIDS)—disease caused by human immunodeficiency virus (HIV);
- Autoimmune diseases (e.g., rheumatoid arthritis, lupus, multiple sclerosis, under- or overactive thyroid)—disease caused by the body's immunologic attacks against its own tissues;
- Inherited immune deficiency syndromes (e.g., ataxia telangiectasia); or
- Organ transplants that require the use of immunosuppressant drugs.
Some experts believe that HD is caused by a complex deficiency in cellular immunity. Such a deficiency may be due to chronic overstimulation by cytokines—substances that draw germ-fighting white blood cells to areas of infection.
The rates of lymphoma and leukemia (e.g., chronic lymphocytic leukemia, CLL) are especially high in some Jewish populations, whereas Asian populations rarely develop CLL. Among first-degree relatives (parents, children, siblings) of CLL patients there is a two- to four-fold increased risk for this cancer.