Recurrent chromosome aberrations in cancer

Cytogenetic investigations of neoplastic cells during the past 25 years hav e revealed more than 600 acquired, recurrent, balanced chromosome rearrange ments, and it has been established that every tumor type, studied in a suff icient number to permit conclusions, may be subdivided on the basis of spec ific, and even pathognomonic, abnormalities. At the molecular level, the ba lanced rearrangements exert their action through one of two alternative mec hanisms: Deregulation of one gene by relocation to an immunoglobulin or T-c ell receptor gene, or the creation of a hybrid gene by the fusion of parts of two genes. At present, nearly 100 genes have been found to be involved i n neoplasia-associated chromosomal rearrangements, the great majority in he matological disorders. At the same time, the clinical usefulness of various cytogenetic abnormalities as diagnostic and prognostic aids has been incre asingly appreciated. The identification of a recurring chromosome abnormali ty can assist in the diagnosis and subclassification of a malignant disease and, hence, in the selection of the appropriate treatment. The karyotype i s also an independent prognostic factor. In hematological neoplasms, where the knowledge of chromosome abnormalities still is much more complete than is the case with solid tumors, cytogenetic analysis now plays an integral p art in the diagnostic work-up of individual patients. Data obtained during recent years strongly suggest that corresponding breakthroughs will be achi eved in solid tumors within a not-too-distant future. (C) 2000 Elsevier Sci ence B.V. All rights reserved.