FISH: a useful technique in the verification of clonality of random chromosome abnormalities

Random chromosome abnormality is an important issue in clinical cytogenetics, especially in cancer cytogenetics. The significance of random abnormalities needs to be well defined. In the present study, ten patients with malignant hematologic disorders were analyzed by classical cytogenetic techniques and fluorescence in situ hybridization (FISH) procedures. Cytogenetic studies showed all ten patients to have a single cell with trisomy, i.e., +8, +8 (5 cases), +12, +15, +18, +20, and +21, respectively. FISH necessitated revision of the cytogenetic diagnosis and confirmed the clonality of these "random" abnormalities.