Cytogenetics as an aid in the diagnosis of lymphomas

Multiple classifications of lymphomas are available. Generally distinctions are made to identify low, intermediate, and high-risk groups. Histopatholo gic differentiation is at times difficult. The revised European-American ly mphoma classification (REAL) uses histology, clusters of differentiation ma rkers, histochemistry, and cytogenetics for definitive identification. This work reviews the karyotypic and FISH (fluorescent in situ hybridization) f indings in some common lymphomas. B-Cell lymphomas, which make up approxima tely 85-90% of lymphomas, are associated with cytogenetic changes of + 12, 13q14, 14q32, 2p11, and 22q13. Translocations help to support the diagnosis of follicular cell lymphoma t(14;18),(q32;q21), mantle cell lymphoma t(11; 14)(q13;q32), and Burkitt's lymphoma t(2;8),t(8;14) and t(8;22). T-Cell lym phomas may show changes in 14q11,7p or 7q. Many of the lymphomas are charac terized by complex karyotypic changes. Specific FISH probes are useful in d etermining characteristic or identifying marker chromosomes. Cytogenetic an d FISH studies aid in the diagnosis, correct classification, and evaluation of therapy for a variety of lymphomas.