USE OF FLUORESCENCE IN-SITU HYBRIDIZATION FOR RETROSPECTIVE DETECTIONOF ANEUPLOIDY IN MULTIPLE-MYELOMA

In malignancies with a low mitotic index such as multiple myeloma (MM) , conventional cytogenetic studies may not be informative. This study' s purpose was to assess specific numerical chromosomal aberrations in non-dividing MM cells by fluorescence in situ hybridization (FISH) of DNA chromosome probes on bone marrow smears. Old air-dried bone marrow smears from 18 MM patients were probed with alpha satellite DNA seque nces for chromosomes 7, X, and Y, and a whole painting probe for chrom osome 11. Plasma cells were identified by their morphologic characteri stics so that counts of fluorescent signals in the nuclei of MM cells could be differentiated from those of normal marrow cells. Numerical c hromosome aberrations were found in 66.7% of the cases (12 of 18), inc luding 5 cases of trisomy 7, 2 cases of tetraploidy, 2 cases of monoso my X in females, 2 cases of disomy X in males, and 1 case of nullisomy Y. In addition, 2 of the 7 cases probed with chromosome 11 paint demo nstrated 3 signals in about 15% of the cells. This study illustrates t he advantages of FISH for interphase analysis of chromosome aberration s in slowly dividing cells, as well as the ability to use old slides f or retrospective studies. (C) 1993 Wiley-Liss, Inc.