The causes of malignant lymphoma are the result of multiple factors. First, it is associated with infections by bacteria or viruses, such as the well-documented chronic infection with Helicobacter pylori, which is closely related to the occurrence of lymphoma associated with the gastric mucosa. Second, immunodeficiency conditions, like in AIDS patients or those who have been taking immunosuppressive drugs for a long period, have a higher likelihood of developing malignant lymphoma compared to the general population. Third, chemical or physical factors, such as environmental carcinogens and electromagnetic radiation, can also lead to malignant lymphoma. Other factors, such as long-term use of certain drugs like phenytoin or pseudoephedrine, and a genetic predisposition, can also be causes of malignant lymphoma.