Lymphomas and leukemias due to infectious organisms.

World-wide, approximately 25% of all human malignancies are caused by infectious organisms, including approximately 10% of cancers occurring in resource rich areas of the world. While some of these disorders are more likely to be seen in patients with underlying immunodeficiency, this is not a requisite for development of malignancy, and most patients, in fact, are not immune-suppressed at the time of diagnosis. In considering hematologic malignancies, several organisms have been implicated in disease etiology. These organisms include Human Herpesvirus 8 (HHV8/KSHV), which is linked to primary effusion lymphoma and to multicentric Castleman s disease, as well as to development of Kaposi's sarcoma; Epstein Barr Virus (EBV) which has been associated with Burkitt lymphoma and nasal T cell lymphoma, among others; Human T lymphotrophic virus type I (HTLV 1), which is associated with Adult T cell leukemia/lymphoma (ATLL); Hepatitis C virus, associated with splenic marginal and other lymphomas; and Helicobacter pylori, associated with gastric MALT lymphoma. The presentation will focus on the latter three disorders, describing pathogenesis of disease, clinical manifestations and therapeutic options.