How non-Hodgkin lymphoma develops
Non-Hodgkin lymphoma, like other cancer types, is a disease of the body's cells.
The body is made up of cells that need to be replaced as they age or are damaged. This happens by cell division, which is when a cell divides and makes a new copy of itself.
Normally, cell division is carefully controlled so the right amount of cells are made to meet the needs of the body. However, if for some reason this process gets out of control, too many cells are made and a cancer can develop.
In NHL, blood cells called lymphocytes become abnormal. These abnormal lymphocytes (lymphoma cells) keep dividing and grow out of the body’s control. Over time, the number of lymphoma cells increases and they form a lump called a tumour. It can help to understand more about the lymphatic system.
The most common place for this to happen is in the lymph nodes. But, NHL can begin in almost any part of the body including in the stomach, small bowel, skin, tonsils, thyroid or testicles. Lymphoma that grows outside the lymph nodes is called extranodal lymphoma.
Because lymphocytes travel around the body, NHL can spread from where it first started. It can spread through the lymphatic system from lymph nodes in one part of the body to lymph nodes elsewhere. Lymphoma cells can also travel in the bloodstream to organs such as the spleen, bone marrow, liver or lungs. When the lymphoma cells reach a new area, they may carry on dividing and form a new tumour.
Lymphoma cells generally start to grow in lymph nodes, which are part of the lymphatic system. Usually NHL affects groups of lymph nodes in one area of the body. However, the lymphoma cells can sometimes spread through the lymphatic system to lymph nodes in other parts of the body. They can also go into the bloodstream, which may carry them to other organs. When the cells reach a new area they may go on dividing and form a new tumour.
To find out more about how cancer develops, watch our introduction to cancer, cancer treatments and living with cancer.