VIM and cancer: To verify that two major cell types of interest (epithelial tumor cells and cancer-associated fibroblasts) were preserved, we performed immunofluorescence staining for the markers cytokeratin 19 (CK19), a marker of keratin, normally expressed by epithelial cells in the lining of the gastroenteropancreatic tract, and vimentin, a marker of mesenchymal cells such as fibroblasts.