Etiologic Heterogeneity Among Non-Hodgkin Lymphoma Subtypes: The InterLymph Non-Hodgkin Lymphoma Subtypes Project

Non-Hodgkin lymphoma (NHL) is the most common hematologic malignancy and the fifth most common type of cancer in more developed regions of the world (1). Numerous NHL subtypes with distinct combinations of morphologic, immunophenotypic, genetic, and clinical features are currently recognized (2,3). The incidence of NHL subtypes varies substantially by age, sex, and race/ethnicity (4–7). However, the etiological implications of this biological, clinical, and epidemiological diversity are incompletely understood. The importance of investigating etiology by NHL subtype is clearly supported by research on immunosuppression, infections, and autoimmune diseases, which are the strongest and most e…