Freeze fracture scanning electron micrograph of a blood vessel that has grown into a melanoma and is providing nourishment to it. Numerous red blood cells (colored red) and three white blood cells (colored yellow) can be seen within the blood vessel (colored yellow/green). This is surrounded by the melanoma (coloured brown) which is from mouse skin. Horizontal width of image is approximately 230 micrometres. Supplied by S. Gschmeissner, K. Hodivala-Dilke & M. Stone, courtesy of Wellcome Images.