Abstract

Technology Spotlight Presentation: Imaging Flow Cytometry Enhances the Detection and Quantification of Rare Events Such as Circulating Tumor Cells and Minimal Residual Disease

Peter Rhein, Application Scientist, Merck

Detection of rare events by Flow Cytometry is often hampered by the limited amount of information that can be gathered from light scatter signals and fluorescence. For rare events detection discrimination of relevant events and artifacts is absolutely mandatory and requires complex and challenging experimental design for traditional flow cytometers. Clinical relevant examples are circulating tumor cells (CTCs), released into the bloodstream from primary and metastatic cancers and tumor cells persisting during therapy (minimal residual disease, MRD). Both CTCs and MRD cells have important prognostic and therapeutic implications and are valuable tools for understanding tumor biology. The ImageStream^® is a multispectral imaging flow cytometer that helps to overcome these obstacles by combining the statistical power of flow cytometry with imaging content of microscopy. Here we show the significance of the imagery for the detection of CTCs by preventing the misclassification of EpCAM⁺CD45⁺ events as leukocytes and undercounting of CTC doublets as single cells. Moreover, we also demonstrate the feasibility of Fluorescence in Situ Hybridization in flow for the detection of chromosomal aberrations in primary samples of patients with relapsed Acute Lymphoblastic Leukemia. These examples show that imaging cytometry contributes to significantly improve the detection and functional analysis biological rare events.