Transmission electron micrograph of an inter- cellular junction or desmosome in a human mesothelioma (a tumour of the epithelium of the pleura, peritoneum or pericardium). Desmosomes form the commonest type of junction between epithelial cells, providing points of cohesion & acting as anchorage points for the cytoskeleton of each cell. The dark linear structure running diagonally across the image is the desmosome. Dense plaques are seen at the junction, lying immediately beneath the membranes. Fine fibres called tonofibrils extend from the plaques into the cell cytoplasm on either side of the junction. Magnification: x98,000 at 8x10 inch size.