ADVANTAGES AND LIMITATIONS OF USING FLUORESCENCE IN-SITU HYBRIDIZATION FOR THE DETECTION OF ANEUPLOIDY IN INTERPHASE HUMAN-CELLS

Fluorescence in situ hybridization with chromosome-specific DNA probes is being increasingly utilized for the detection of chromosome aberra tions induced in vitro and in vivo by chemical and physical agents. Al though potentially a powerful technique, FISH studies for aneuploidy c an be heavily influenced by cellular phenomena and hybridization artif acts which make the performance and interpretation of the results diff icult. As a consequence, frequently hyperdiploid frequencies are repor ted in the literature which are substantially higher than one would ex pect based upon frequencies seen in conventional metaphase analyses. I n this article, a number of the potential pitfalls that we have encoun tered while performing FISH analyses for aneuploidy are discussed and their potential impact on the observed hybridization frequencies is de scribed. After considering these factors, the frequencies of lymphocyt e nuclei containing 3 and 4 chromosome copies are compared between met aphase values obtained from published human population studies and int erphase values obtained from similar studies using FISH. It is conclud ed that by using caution in the evaluation of slides, interphase studi es using FISH to detect hyperdiploidy and polyploidy can provide estim ates of numerical alterations which closely reflect those seen during metaphase analysis using either FISH or conventional approaches. Howev er, due to the inability of interphase analysis to distinguish hyperdi ploidy from polyploidy as well as other potential problems, frequencie s of aneuploid nuclei obtained using single label FISH should only be considered approximations of absolute frequencies. For additional accu racy, multi-color FISH with two or more different probes should be per formed.