Fig 4. Spheroid cultures preserve cytokeratin 20 expression of their original tumours.

(A) Immunostaining of spheroids and corresponding tumours from two different patients for epithelial cell marker EpCAM (red) and gastrointestinal epithelial marker cytokeratin 20 (green). Nuclei are stained with Hoechst (blue). Spheroids were stained after 10 days of culture. Size bars = 50 μm. (B) No significant difference in percentage of EpCAM-positive cells stained for cytokeratin 20 in tumours and spheroid cultures at day 3 and day 10 (p = 0.149) was observed.