Mantle cell lymphoma, a cancer that is a type of non-Hodgkin's lymphoma, affects the white blood cells, which are cells that respond to infections in the body, according to WebMD. Mantle cell lymphoma is specific to the type of white blood cells called lymphocytes.
The small immune system glands that are found throughout the body, the lymph nodes, contain the lymphocytes. When some of the lymphocytes known as "B-cell" lymphocytes become cancerous and begin to grow uncontrollably, this is called mantle cell lymphoma. In time, the cancerous cells turn into lymph node tumors. These can spread through the bloodstream to other lymph nodes, and to other parts of the body such as the liver, spleen, bone marrow and digestive tract. In many cases, this happens before someone is even diagnosed with mantle cell lymphoma.
The exact cause of mantle cell lymphoma is unknown as of 2015, but it is thought that most people who contract this condition have a genetic mutation that affects the B-cell lymphocytes by triggering the release of a surplus of cyclin D1, a protein which controls the growth of cells. This increase causes mantle cell lymphoma by making a particular type of B-cell grow uncontrollably. In most cases, this condition is incurable, but with treatment, patients can often have a better quality of life and live longer.