Although the uncontrolled growth process is understood, the precise mechanism that initiates the cancerous growth cycle in unknown. Certain risk factors associated with lymphoma have been identified. Not everyone who develops lymphoma has a recognizable risk factor, and people with one or more risk factors never go on to develop a lymphoma.
Exposure to chemicals, including pesticides and herbicides, is linked with lymphoma. Solvents, such as benzene, acetone, turpentine, toluene, and alcohols, are found in a number of commonly used products, including gasoline. The incidence of lymphoma tends to be higher in agricultural areas, largely because of chemicals found in pesticides and herbicides.
Other than chemical exposure, older age increases a person’s risk for developing lymphoma, especially NHL. Medications that suppress the immune system, such as anti-rejection drugs, also raise a person’s risk for developing lymphoma. A history of certain infections also is associated with an increased risk. Epstein-Barr virus, human immunodeficiency virus, hepatitis C, and infection with Helicobacter pylori are all linked to lymphoma.