EFFICACY OF CURRENT MOLECULAR CYTOGENETIC PROTOCOLS FOR THE DIAGNOSISOF CHROMOSOME-ABERRATIONS IN TUMOR SPECIMENS

Molecular cytogenetics provides a powerful link between molecular gene tic analysis and chromosome morphology, allowing one to pinpoint struc turally aberrant chromosome regions on the molecular level. Fluorescen ce in situ hybridization with selected DNA probes allows the design of efficient and sensitive tools for the diagnosis of chromosomal aberra tions present in tumor cells. Comparative genomic hybridization (CGH) allows the identification of chromosomal imbalances in a comprehensive manner, and is applied to solid tumors and hematological malignancies in order to (i) identify clonal differences within a specimen, (ii) c ontribute to tumor classifications, (iii) identify recurrent chromosom al gains and losses as starting points for the characterization and is olation of pathogenetically relevant genes, such as proto-oncogenes an d tumor suppressor genes respectively, (iv) identify imbalances of pro gnostic relevance, (v) detect high-copy-number amplifications and othe r markers of genetic instability, and (vi) analyze chromosomal imbalan ces during tumor progression.