A risk factor [2] is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do.

The cause of Hodgkin lymphoma is unknown, although infection with the Epstein-Barr virus may play a role in the development of the cancer in approximately 30% of children and teens. People with immune system problems also have a higher risk of developing Hodgkin lymphoma. This group includes:

• Children born with the hereditary condition of ataxia telangiectasia [3], which causes immune system problems
• Children with human immunodeficiency virus (HIV) [4], the virus that causes acquired immune deficiency syndrome (AIDS)

Children who are taking drugs that suppress the immune system following an organ transplant