Malignant lymphoma may be genetically related, and sometimes a significant family aggregation can be seen. Some studies have found that people with a family history of malignant lymphoma have a higher probability of developing malignant lymphoma. For example, people with a history of malignant lymphoma in their father or mother have a higher incidence of malignant lymphoma than the general population. It has also been found that people with 1st degree relatives who have malignant lymphoma are also more likely to develop malignant blood disorders than the general population. If one of the identical twins develops malignant lymphoma, the risk of the other one developing lymphoma is also significantly higher. So heredity plays a role in lymphoma. Of course, besides heredity, lymphoma is also related to other factors such as immune deficiency and infection.