Update on burkitt lymphoma and leukemia.

DH Burkitt lymphoma and Burkitt leukemia (also called mature B-cell acute lymphocytic leukemia [ALL]) have identical cytogenetic aberrations, surface markers, and molecular genetics. The clinical manifestations of Burkitt lymphoma resemble more of high grade malignant lymphomas, whereas B-cell ALL is similar to other subtypes of ALL. Additionally, there is a substantial difference in epidemiology. Burkitt lymphoma is endemic in Africa and a rare disease entity in western countries. In HIVinfected patients, Burkitt lymphoma is one of the most predominant malignancies as a secondary event. The cytogenetic aberrations are identical in Burkitt lymphoma and mature B-cell ALL: the translocations t(8;14)(q24;q32), t(8;22)(q24;q11), the latter reflecting chromosome 8q24 juxtaposed to the immunoglobulin heavy chain gene locus on chromosome 14q32, and least frequently, the translocation t(2;8)(p12;q24) involving the immunoglobulin kappa gene locus on 2p12. The surface immunoglobulin is present in both mature B-cell ALL and Burkitt lymphoma, whose cells are usually terminal deoxynucleotidyl transferase (TdT)-negative. The CD19 antigens, as well as the CD20 antigens, are expressed in more than 90% of cells in both disease entities, which are of potential interest for the development of specific antibody therapies.