Characterization of chromosomal abnormalities in uroepithelial carcinomas by G-banding, spectral karyotyping and fish analysis

Chromosome analysis by G-banding, spectral karyotyping (SKY) and fluorescen ce in situ hybridization (FISH) was per formed on 24 short-term cultured tr ansitional cell bladder carcinomas and 5 cell lines established from bladde r carcinomas. Except for one tumor with an apparently normal chromosomal co nstitution, clonal chromosome abnormalities were detected in all examined c ases by the combined approach. The application of SKY and FISH techniques i mproved the karyotypic descriptions, originally based on C-banding only, by identifying 32 additional numerical changes, by establishing the chromosom al origin of 27 markers and 2 ring chromosomes, by redefining 53 aberration s and by detecting 15 hidden chromosomal rearrangements. No recurrent trans location, however, was detected. The most prominent: karyotypic feature was thus the occurrence of deletions and losses of whole chromosome copies ind icating the importance of tumor suppressor genes in transitional cell carci noma pathogenesis. Invasive carcinomas were karyotypically more complex tha n were low grade superficial tumors. Specific leases of material from chrom osome 9 and from chromosome arms I Ip and 8p, and gains of 8q and Iq seem t o be early changes appearing in superficial tumors, whereas losses from 4p and 17p and the formation of an isochromosome for 5p were associated with m ore aggressive tumor phenotypes, (C) 2001 Wiley-Liss. Inc.