CSC pancreatic cancer spheroids and expression of pancreatic CSC markers. Pancreatic cancer spheroids were generated from human pancreatic PANC-1 cancer cells as described in the Section 2, and the corresponding differential interference contrast (DIC) microscopy images are shown (a). Pancreatic cancer spheroids were analyzed for the expression of CD44 (b), CD24 (b,c), EpCAM (c), PAX (d) and PDX1 (d) by confocal microscopy as described in the Section 2. DIC images are also shown. The cells were also stained for nuclei with 4′,6-diamidino-2-phenylindole (DAPI) (blue fluorescence). Bar, 25 μm. Data are representative of at least three independent experiments.