Circulating tumor cells from pancreatic cancer patients. Immunofluorescence microscopy (20×) demonstrating (A) pan-cytokeratin-positive and vimentin-negative CTC (merge), (B) DAPI (blue), (C) pan-cytokeratin (green), (D) absence of vimentin (red); and (E) pan-cytokeratin-positive and vimentin-positive CTC (merge), (F) DAPI (blue), (G) pan-cytokeratin (green), and (H) vimentin (red).