KRT14 and neoplasm: To evaluate the contribution of distinct epithelial subpopulations to cell plasticity and tumor heterogeneity, PDOs were treated with TGF-β (EMT-medium) for 3, 7 and 10 days, and immunolabeled with antibodies for luminal cytokeratin 8 (CK8) and myoepithelial cytokeratin 14 (CK14) (Figure 6).