Original ArticleTrisomy 12 assessment by conventional fluorescence in-situ hybridization (FISH), FISH in suspension (FISH-IS) and laser scanning cytometry (LSC) in chronic lymphocytic leukemia

- First illustration of combining FISH with flow cytometry (FISH-IS) to aneuploidy detection in CLL patient samples.
- This study proves FISH-IS accurately differentiates between monosomy, disomy and trisomy at a threshold of 1% in CLL.
- Three current cytogenetic methods each have different abilities in detecting low frequency trisomy 12 clones in CLL.

Chronic lymphocytic leukemia (CLL) has an extremely heterogeneous clinical course, and prognostication is based on common genetic abnormalities which are detected by standard cytogenetic methods. However, current methods are restricted by the low number of cells able to be analyzed, resulting in the potential to miss clinically relevant sub-clonal populations of cells. A novel high throughput methodology called fluorescence in situ hybridization in suspension (FISH-IS) incorporates a flow cytometry-based imaging approach with automated analysis of thousands of cells. Here we have demonstrated that the FISH-IS technique is applicable to aneuploidy detection in CLL samples for a range of chromosomes using appropriate centromere probes. This method is able to accurately differentiate between monosomy, disomy and trisomy with a sensitivity of 1% in CLL. An analysis comparing conventional FISH, FISH-IS and laser scanning cytometry (LSC) is presented.