Primary immunodeficiencies: genetic risk factors for lymphoma.

It has been estimated that up to 25% of patients with certain genetically determined immunodeficiencies will develop tumors, primarily B-cell lymphomas, during their lifetime. Epstein-Barr virus appears to be an important cofactor in the development of lymphoproliferative disorders in patients with primary immunodeficiencies, as well as acquired immunodeficiencies. Additionally, host defects in immunoregulation and/or gene rearrangement, which are features of certain primary immunodeficiencies, probably contribute to the risk of lymphomagenesis in patients at risk.