Cross-species color banding in ten cases of myeloid malignancies with complex karyotypes

Cross-species color banding is a multiple-color fluorescence in situ hybrid ization (FISH) technique using probes developed from other animal species. Hybridization to human metaphases produces color banding patterns specific for each homologous chromosome pair. The technique has been evaluated in a complementary manner with G-banding and chromosome painting in a series of 10 myeloid malignancies with complex or unresolved karyotypes. Color bandin g detected the majority of chromosomal abnormalities, which had been identi fied by G-banding and in each case revealed chromosomal changes that G-band ing had not identified. Painting was necessary to confirm these abnormaliti es due to the limitation of only seven colors in the color-banded karyotype . At the same time, painting fortuitously uncovered cryptic abnormalities i n 6 of 10 cases that had not been detected by color banding. Insertions wer e visible by painting only. This study has demonstrated that in the analysi s of complex karyotypes, the application of color banding revealed the invo lvement of the long arm of chromosome 3, indicating a poor risk, in two cas es not identified by G-banding. Therefore, these techniques applied togethe r have revealed cryptic chromosomal abnormalities with prognostic significa nce, which in some cases may have implications for patient management. (C) 2001 Wiley-Liss, Inc.