In most cases, the cause of lymphoma in children is unknown. It is assumed that risk factors for adult Hodkin's and non-Hodgkin disease are similar in children.
Debilitated immune system
- Immune defects/treatment with immune-suppressing drugs. Children with immune defects or children using immune suppressing medications over long periods of time have a greater risk.
The connection between this virus (the cause of mononucleosis) and lymphoma is unclear. For Hodgkin's lymphoma, the virus expresses itself in the cancer cells (Hodgkin and Reed-Sternberg cells) in some of cases, but the role it plays in the development of cancer is unknown. Burkitt's lymphoma occurs often in the belt of Africa strongly affected by malaria. This subgroup of non-Hodgkin lymphoma makes up almost half of the collective number of childhood cancer in this area. The malignant cell is almost always infected with Epstein-Barr virus, and the theory is that there is an interaction between chronic malaria infection and Epstein-Barr virus infection that can induce the development of a malignant cell (4). The Epstein-Barr virus also plays a role in the development of many lymphomas occurring in patients with immune defects or HIV infection.
Previous treatment with chemotherapy/radiation therapy
Non–Hodgkin lymphoma has been observed as a secondary cancer after treatment for Hodgkin's lymphoma. This applies to treatment with chemotherapy alone or chemotherapy combined with radiation therapy. Almost 5% of adults treated for Hodgkin's lymphoma develop non-Hodgkin lymphoma at a later point in time. For children, the risk appears to be lower (8).
There is no clear relationship between lymphomas and specific inherited genes, even if similarities are implied for certain HLA antigens. Data shows that there is an increase in incidence of Hodgkin's lymphoma in parents and siblings (about double). Certain hereditary immune defects are associated with a higher risk for lymphoma in childhood (Ataxia telangiectasia, Wiskott-Aldrich syndrome, CVID, SCID, XLP).