Hematologic Malignancies

Chromosome aberrations, mostly translocations, and viral infections are frequent causes for hematologic malignancies. The clonal development of T- and B-lymphocytes is physiologically associated with DNA recombination, and chromosome translocations in B- and T-cell neoplasia may reflect the aberrant activation of normal translocation processes [Tsujimoto et al. 1985]. Other pathogenetic origins for lymphoma are less common. They include occupational factors (farming, pesticide application, floor milling), exposure to certain chemicals (pesticides, herbicides, solvents), and immune deficiency. Connective tissue disorders (Sjögren syndrome, rheumatoid arthritis, chronic lymphocytic thyroiditis, systemic lupus erythematosus) are also associated with an increased risk for lymphoma. There is an increased incidence in gastrointestinal lymphomata in patients with celiac sprue and inflammatory bowel disease. Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is frequently associated with Helicobacter pylori infection.