There is no evidence that either Hodgkin lymphoma or any of the non-Hodgkin lymphomas can be passed from one generation to the next. There is nothing to suggest an inherited risk for developing these types of cancer.

Over the last few decades it has become clear that non-Hodgkin lymphoma is becoming commoner (the reasons for this are not known). The fact that it is becoming more frequent does mean that very occasionally two members of the same family will develop the condition. When this does happen it is probably just pure chance, or bad luck, and in all likelihood not a result of any genetic link in the family leading to the cancer.

There are, however, a few rare disorders of the immune system, which are caused by abnormal genes, which can be passed from one generation to the next and which carry an increased risk of developing non-Hodgkin lymphoma. These include:

• Wiskott-Aldrich syndrome
• hereditary ataxia telangiectasia
• common variable immunodeficiency
• X-linked lymphoproliferative syndrome

These are all very rare conditions. When they do occur they lead to 'clusters' of non-Hodgkin lymphoma within a family so there is always an obvious history of a number of family members having lymphomas.