IDENTIFICATION OF GENETIC IMBALANCES IN MALIGNANT-LYMPHOMA USING COMPARATIVE GENOMIC HYBRIDIZATION

In comparison to leukemias, the clinical relevance of chromosomal aber rations in non-Hodgkin's lymphoma (NHL) is not as well understood. Thi s is primarily due to limitations of chromosomal banding techniques wh ich have been the central methods for cytogenetic analysis. These tech niques depend on the availability of fresh tumor tissue and the examin ation of metaphase cells which may not be representative for the major cell clone in vivo. In contrast, the new technique of comparative gen omic hybridization (CGH) allows researchers to obtain a comprehensive view of chromosomal gains and losses by analyzing tumor DNA, which can be prepared from archival tissue samples. Results of CGH studies in t hree different types of lymphoproliferative disorders are outlined in this paper demonstrating that: (1) in chronic B cell leukemias, chromo somal aberrations are missed by banding analysis in a high proportion of cases, (2) CGH on paraffin-embedded tissue samples can be used for cytogenetic analysis within clinical multicenter trials and (3) DNA am plifications are more frequent in NHL than previously assumed, Thus, i t can be expected that CGH will contribute both to the understanding o f pathogenetic mechanisms and the identification of clinically relevan t chromosome aberrations in NHL.