Morphology of gastric carcinoma cell lines grown as monolayer cultures or as three dimensional spheroids. (A) The cell lines show a slightly different epithelial morphology. Most cells of all cell lines contain a characteristic intracellular vacuole (arrows) which probably contains mucinous material stained red by the PAS method (last picture right in lower panel). (B) Spheroid formed by culturing mGC8 tumor cells on soft agar: left, phase contrast; right, fluorescence staining of necrotic cells with propidium iodide (red) and apoptotic cells with FITC-labeled annexinV (green, marked by arrowheads) as described in "Material and Methods". Magnification: bars correspond to 10 μm. mGC, murine gastric carcinoma.