Nobody knows what causes lymphoma.

It is more common in people who:

• have a weakened immune system from conditions such as an inherited immune disorder, an autoimmune disease or HIV infection or AIDS
• take medicines that suppress the immune system after having an organ transplant
• are infected with the Epstein-Barr virus (which causes glandular fever, especially if the immune system is already weakened) or some other viruses or bacteria
• have a family history of lymphoma
• are exposed to some toxins in the environment
• smoke cigarettes.

Even if you have one or more of these risk factors, it does not mean you will develop lymphoma. If you suspect you or some you know has lymphoma, it is important to see your doctor soon as possible.