Comparison of comparative genomic hybridization and interphase fluorescence in situ hybridization in ovarian carcinomas: possibilities and limitations of both techniques.

Comparative genomic hybridization (CGH) is a valuable technique for cytogenetic analysis of solid tumors. To evaluate the reliability of CGH, we examined DNA of 10 ovarian carcinomas after CGH analysis with single- and double-locus fluorescence in situ hybridization (FISH). The FISH experiments, involving 5 chromosomes (chromosomes 3, 6, 8, 12, and 18) with different FISH probes, confirmed the CGH results in 66.2% of cases (92 of 139 investigated loci). In 4 patients, inconsistent results (41 loci) were related to polyploidy, because CGH cannot detect polyploid karyotypes. The remaining 6 discordant loci can be referred to limitations in both techniques. Re-evaluation of FISH and CGH results by one other is therefore recommended to overcome these technical artifacts. Nevertheless, CGH is of potential value in characterizing chromosomal alterations and might help in generating tumor-specific sets of FISH probes to obtain genetic information of prognostic value within a few days.