Often, structures that contain cells with an unpolarized distribution of prominin-1 immunoreactivity were found in the vicinity of numerous intact or disrupted thin-walled blood vessels (Fig. 4F–H, red asterisk) suggesting a potential communication of erythrocytes with tumor cells and/or secreted materials (Fig 4G–I, S3C, red and blue arrowheads). This evidence concerns the gene PROM1 and neoplasm.