Evaluation of 24-color multifluor-fluorescence in-situ hybridization (M-FISH) karyotyping by comparison with reverse chromosome painting of the humanbreast cancer cell line T-47D

Multifluor-fluorescence in-situ hybridization (M-FISH) chromosome paints fo r all the chromosomes in the human complement labeled with different combin ations of fluorochromes is a recent technological development enabling assi gnment of chromosomal material to rearranged chromosomes. Little data is av ailable on the accuracy and limitations of the approach to the analysis of complex karyotypes, which are characteristic of many malignant diseases. He re we compare M-FISH analysis of the breast-cancer-derived cell line T-47D with a previous analysis by reverse chromosome painting analysis of flow-so rted chromosomes from the same material. This demonstrated a high degree of concordance. It also illustrated the limitations of M-FISH analysis, inclu ding difficulties identifying small regions of chromosomal material and int rachromosomal rearrangements. Confirmation of selected aberrations using le ss-complex mixtures of painting probes and further definition of abnormalit ies using single copy markers may be required. The detailed karyotype descr iption possible by M-FISH analysis contrasts with the definition in the ori ginal G-banding analysis. This and the level of concordance with reverse FI SH painting supports the utility of the approach in the definition of compl ex karyotypes.