Detection of trisomy 8 on blood smears using fluorescence in situ hybridization

In this study, fluorescence in situ hybridization (ISH) with an alphoid probe was used for the detection of trisomy 8 on archival blood smears (BS). The results were compared with hybridization experiments performed on methanol/acetic acid fixed cells of cytogenetic preparations (CP) which are widely used for ISH. Five controls and 20 patients with myeloid leukemias were examined. In the controls, CP and BS had the same percentages of cells with two or three fluorescence signals. In 5/20 patients, trisomy 8 was detected both on CP and BS. Two of the patients had 7 to 10% interphase cells with three hybridization signals, indicating the presence of small subclones with trisomy 8; one of the subclones was not detected by G-banding analysis. The remaining 15 patients were disomic for chromosome 8; hybridization results were within the range of the controls both on CP and BS. We conclude that using a chromosome 8 specific alphoid probe, fluorescence ISH to interphase cells can be performed on BS with the same efficiency that is reached on methanol/acetic acid fixed cells of CP.