Non-Hodgkin's lymphoma is cancer of a type of white blood cell in the lymphatic system. This system includes the lymph nodes, spleen, and bone marrow. It drains fluid from tissue and returns it to the blood. It plays an important role in the body's defense against infection.
Non-Hodgkin's lymphoma is classified in several ways. One practical way to classify the disease is by how fast it grows. In this scheme, there are three grades: low-grade, intermediate-grade, and high-grade. Low-grade is the slowest-growing, and high-grade is the fastest.
What is going on in the body?
Non-Hodgkin's lymphoma begins in one type of lymph tissue. It starts either in the lymph nodes, the spleen, the bone marrow, or other less common lymph tissues. Lymph nodes are small, round glands found all over the body.
Lymphoma cells grow and cause lymph nodes and internal organs to enlarge. The lymphoma cells also infiltrate and crowd out the bone marrow. They can invade any other part of the body, including the brain, lungs, kidneys, and skin. They may also invade the hard part of the bone, the intestines, the liver, the spleen, or even the heart. Lymphomas can also cause immune system problems and unusual infections.
Autoimmune disorders are common in people with non-Hodgkin's lymphoma. Autoimmunity means that the body's immune system attacks itself. It may lead to kidney failure, anemia, blood clots, bleeding, arthritis, or nerve damage.
What are the causes and risks of the disease?
Lymphoma occurs when the genes of a white blood cell change enough that the cell grows uncontrollably. How this occurs is an important part of cancer research. Many of the genes that become abnormal and control this cell growth have been described. The exact process, as well as why some people develop lymphoma and others do not, remain unanswered parts of the cancer question.
Some of the risk factors for non-Hodgkin's lymphoma are:
exposure to radiation or certain viruses
inherited or acquired immunodeficiency disorders, such as AIDS
medicines, such as corticosteroids and medicines given after organ transplants
treatments that suppress the immune system, such as chemotherapy
Some autoimmune disorders may increase the risk of non-Hodgkin's lymphoma. Tobacco use does not seem to be a strong risk factor. There is controversy over whether some pesticides or herbicides can cause lymphoma. Non-Hodgkin's lymphoma occurs in all age groups and both genders. Some subtypes are more common in elderly people, and others are more common in young people.