Relationship between chromosomal aberrations by fluorescence in situ hybridization and DNA ploidy by cytofluorometry in osteosarcoma

An analysis of the chromosomal aberrations and DNA ploidy in the interphase nuclei of seven human osteosacomas was preformed by double-target fluoresc ence in situ hybridization (FISH) and DNA cytofluorometry. The FISH study o f the numerical aberrations in chromosomes 1 and 17 or the structural aberr ations in chromosome arm 1p or 17p was carried out by using four locus spec ific DNA markers, with one pair consisting of 1q12 and 1p36 and the other p air consisting of the 17 cemtromere and 17p13.3. There was no significant d ifferences in the percentage of deletions in chromosome 1 and 17 between os teosarcomas and normal tissues. However, all seven tumors studied had extra copies. Cells with more than three probe signals were regarded as having c hromosome polysomy. The percentage of polysomy of chromosome 1 was 20.0-64. 0%, and chromosome 17 was 28.0-60.0%. The DNA ploidy patterns of hyperdiplo id cells showing a greater DNA content than diploid cells were obtained by DNA cytoflurometry. Five of the seven tumors were non-diploid, and the rema ining two were diploid. The percentage of polysomy was correlated with the percentage of hyperdiploid cells in each tumor. Thus, these findings indica ted that the DNA ploidy changes were closely correlated with aberrations in the chromosome copy number in osteosarcomas. (C) 1999 Elsevier Science Ire land Ltd. All rights reserved.