Morphologic variation of circulating tumor cells in metastatic breast cancer patients visualized by immunofluorescent stain pattern.

e21079 Background: Isolation of circulating tumor cells (CTCs) using microfiltration is a growing utility in the field of CTC detection. The microfiltration approach can be used on peripheral blood as a non-invasive liquid biopsy for cancer detection and subtyping. We present a utilization of the CellSieve microfilter to subtype CTCs based on immunofluorescent staining pattern of cytokeratin filamentation and EpCAM surface marker expression. Our initial study on CTCs in patient blood indicates that disseminated CTC populations have high rates of phenotypic heterogeneity. Further detailed molecular analysis and patient tracking of these phenotypes may lead to individualized patient assessment based on CTC characterization. Methods: 7.5 mL of whole blood collected from metastatic breast cancer patients were diluted in a fixative solution. An 8 µm CellSieve precision microfilter was placed into a filter holder and the samples were passed through the filter (~ 90 seconds). The cells captured on the filter wer...