Lymphoma originates in lymph nodes and lymphatic tissues, primarily involving the malignant transformation of specific immune cells during lymphocyte proliferation and differentiation in the immune response process. It is a type of hematologic malignancy.
Based on histopathological changes, lymphoma can be divided into Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). In 1832, Thomas Hodgkin reported a disease characterized by lymph node enlargement and splenomegaly, now known as Hodgkin lymphoma. In 1846, Virchow distinguished a disease from leukemia, referring to it as lymphoma or lymphosarcoma, which is now recognized as non-Hodgkin lymphoma.
Etiology and Pathogenesis
Infections and immune-related factors are generally considered important in the development of lymphoma, while physical, chemical, and genetic factors also play significant roles. The viral hypothesis has gained considerable attention.
Using fluorescent immunoassays, serum from HL patients has revealed high titers of anti-EB (Epstein-Barr) virus antibodies in some cases. Electron microscopy of lymph nodes in HL patients has detected EB virus particles, and EB virus has been identified in Reed-Sternberg (R-S) cells in approximately 20% of HL cases. Over 80% of Burkitt lymphoma patients exhibit significantly elevated serum EB virus antibody titers, whereas this elevation is observed in only 14% of non-Burkitt lymphoma cases. Additionally, individuals with high EB virus antibody titers in the general population show an increased likelihood of developing Burkitt lymphoma. These findings suggest a possible etiological role of EB virus in Burkitt lymphoma. Furthermore, EB virus is also implicated in the pathogenesis of post-transplant lymphomas and AIDS-related lymphomas.
Adult T-cell leukemia/lymphoma (ATLL) in Japan demonstrates a clear familial clustering trend and regional distribution. In the late 1970s, a retrovirus known as human T-cell lymphotropic virus type I (HTLV-I) was confirmed as a causative agent for ATLL. Another retrovirus, HTLV-II, has recently been associated with the development of cutaneous T-cell lymphomas (e.g., mycosis fungoides). Marginal zone lymphomas in patients with concurrent HCV infections have shown partial or complete remission when treated with interferon and ribavirin leading to negative HCV RNA results, suggesting HCV as a contributing factor. Additionally, the presence of Helicobacter pylori (Hp) antigens is strongly linked to the development of gastric extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). Treatment targeting Hp has improved the condition, implicating Hp as a causative factor in this type of lymphoma.
Immunodeficiency is also associated with an increased risk of lymphoma development. Individuals with hereditary or acquired immunodeficiency disorders experience higher rates of lymphoma compared to the general population. Among patients receiving long-term immunosuppressive therapy after organ transplantation, one-third of observed malignancies are lymphomas. Patients with Sjögren's syndrome exhibit a higher incidence of lymphoma compared to the general population.
To be continued