Morphological appearance of the three cell fractions following differential centrifugation followed by culture in selective medium. (a) Organoid fraction. The arrow illustrates a fragment of partially digested tumour that attaches to the substrate of the culture vessel and from which cells with an epithelial-like morphology migrate radially and proliferate. (b) Epithelial fraction. (c) Stromal fraction consisting of fibroblasts. Scale bar = 15 μm.