Figure 3

A. Prekeratin staining of cytospins of sorted CTC fraction after spiking 5.0 × 10 ⁶ Panc-1 cells in 20ml EDTA-treated whole blood. Note the marked cytoplasmatic prekeratin staining of almost all sorted cells indicating very high purity of the sorted fraction. The stained cells have large blue nuclei with prominent nucleoli (arrow) indicating the malignant nature of the enriched PANC-1 cells. PBMCs are marked with an arrowhead. Magnification: 30x, Bars: 25μm. B - Prekeratin staining of cytospins of sorted ‘gated’ fraction (G) after spiking 5.0 × 10⁶ Panc-1 cells in 20ml EDTA-treated whole blood. The sample is mainly composed of two cell types: most are PBMCs with a little amount of non-staining cytoplasma (arrowheads) and a few larger cells with prominent cytoplasmatic prekeratin staining (Panc-1 cells) (arrows). Magnification: 10x, Bars: 25μm. 3C - Prekeratin staining of the sorted CTC fraction after spiking 5.0 × 10⁴ Panc-1 cells in 20ml EDTA-treated whole blood. Cell density is greatly reduced owing to the lower concentration of spiked Panc-1 cells. Despite varying cell size, marked cytoplasmatic prekeratin staining was seen in most cells, indicating high purity of the sorted cells. Magnification: 10x, Bars: 25μm.