What Is Non-Hodgkin Lymphoma?
Lymphoma refers to a malignancy of the lymphatic system. The lymphatic system is a network of nodes (knots of tissue) connected by vessels. Together, the lymph nodes drain fluid and waste products from the body. The lymph nodes act as tiny filters, removing foreign organisms and cells.
Lymphocytes are a type of white blood cell that helps fight infections caused by bacteria, viruses, or fungi. The lymph node function is to prevent infections from entering the bloodstream. When the lymphatic system is fighting an active infection, you may notice that some of the lymph nodes in the area of the infection become swollen and tender. This is the body’s normal reaction to an infection.
Lymphoma occurs when the lymph-node cells or the lymphocytes begin to multiply uncontrollably, producing cancerous cells that have the abnormal capacity to invade other tissues throughout the body. The two main types of lymphoma are Hodgkin lymphoma and non-Hodgkin lymphoma. The differences in these two types of lymphoma are certain unique characteristics of the different lymphoma cells.
Non-Hodgkin lymphoma is further classified into a variety of subtypes based on the cell of origin (B-cell or T-cell), and the cell characteristics. The subtype of Non-Hodgkin lymphoma predicts the necessity of early treatment, the response to treatment, the type of treatment required, and the prognosis.
Non-Hodgkin lymphoma is much more common than Hodgkin lymphoma. Non-Hodgkin lymphoma is the seventh most common cause of cancer-related deaths in the United States. The risk of developing non-Hodgkin lymphoma increases with age and it is more common in males than in females and in Caucasians. North America has one of the highest incidence of non-Hodgkin lymphoma.
What Causes Non-Hodgkin Lymphoma?
The exact cause of non-Hodgkin lymphoma is unknown. However, there are multiple medical conditions that are associated with an increased risk of developing the disease:
- Inherited immune deficiencies
- Genetic syndromes: Down syndrome, Klinefelter's syndrome (a genetic condition in men caused by an extra X chromosome)
- Immune disorders, and their treatments: Sjögren's syndrome (an immune disorder characterized by unusual dryness of mucous membranes), rheumatoid arthritis, systemic lupus erythematosus
- Celiac disease, a disease involving the processing of certain components of gluten, a protein in grains
- Inflammatory bowel disease, particularly Crohn’s disease, and its treatment
- Family history of lymphoma
- Bacteria: Helicobacter pylori, associated with gastritis and gastric ulcers; Borrelia burgdorferi, associated with Lyme disease; Campylobacter jejuni; Chlamydia psittaci
- Viruses: HIV, HTLV-1, SV-40, HHV-8, Epstein Barr virus, hepatitis virus
- Non-random chromosomal translocations and molecular rearrangements
Other Factors Include:
- Regular exposure to certain chemicals, including insect and weed killers, and a number of chemicals used in industries such as farming, welding, and lumber
- Exposure to nuclear accidents, nuclear testing, or underground radiation leaks
- Treatment with immunosuppressant drugs, for prevention of organ transplantation rejection, or for treatment of inflammatory and autoimmune disorders
- Tumor necrosis factor agents used to treat psoriatic and rheumatoid arthritis and inflammatory bowel disease
- Prior exposure to chemotherapy and/or radiation used to treat a prior diagnosis of cancer
- Treatment with a medication called Dilantin (phenytoin), commonly used to treat seizure disorders
- Use of hair dyes, especially dark and permanent colors, used before 1980 (research is inconclusive)
- High levels of nitrates found in drinking water
- Diets high in fat and meat products
- Ultraviolet light exposure
- Alcohol intake