What Is Non-Hodgkin's Lymphoma?
Non-Hodgkin's lymphoma (also called NHL) is cancer that begins in the lymphatic system. To understand this disease, it is helpful to know about the lymphatic system.
The Lymphatic System
The lymphatic system is part of the body's immune system. The immune system fights infections and other diseases.
In the lymphatic system, a network of lymph vessels carries clear fluid called lymph. Lymph vessels lead to small, round organs called lymph nodes. Lymph nodes are filled with lymphocytes (a type of white blood cell). The lymph nodes trap and remove bacteria or other harmful substances that may be in the lymph. Groups of lymph nodes are found in the neck, underarms, chest, abdomen, and groin.
Other parts of the lymphatic system include the tonsils, spleen, and thymus. Lymphatic tissue is also found in other parts of the body including the stomach, skin, and small intestine.
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| Lymphatic system. |
Non-Hodgkin's Lymphoma
There are many types of non-Hodgkin's lymphoma. All types of lymphoma begin in cells of the lymphatic system. Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place. Sometimes this process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor.
Non-Hodgkin's lymphoma begins when a lymphocyte (a
B cell or
T cell) becomes
abnormal. Usually, non-Hodgkin's lymphoma starts in a B cell in a lymph node. The abnormal cell divides to make copies of itself. The new cells divide again and again, making more and more abnormal cells. The abnormal cells are cancer cells. They do not die when they should. They do not protect the body from infections or other diseases. Also, the cancer cells can spread to nearly any other part of the body.
| | Risk Factors Doctors can seldom explain why one person develops non-Hodgkin's lymphoma and another does not. But research shows that certain risk factors increase the chance that a person will develop this disease. In general, the risk factors for non-Hodgkin's lymphoma include the following: Researchers are studying obesity and other possible risk factors for non-Hodgkin's lymphoma. People who work with herbicides or certain other chemicals may be at increased risk of this disease. Researchers are also looking at a possible link between using hair dyes before 1980 and non-Hodgkin's lymphoma. NCI's booklet Cancer and the Environment has more information about risk factors. Most people who have known risk factors do not get non-Hodgkin's lymphoma. On the other hand, people who do get the disease often have no known risk factors. If you think you may be at risk, you should discuss this concern with your doctor. |
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