Cancer cell death. Coloured scanning electron micrograph (SEM) of a T-lymphocyte or white blood cell (small) recognizing and attaching to the surface of 2 cancer cells (large). Once intimate contact is made, the T-lymphocyte initiates a cytolytic process by releasing chemicals that eventually destroy the cancer cells. The changes that occur to the surface of the cancer cells include loss of microvilli (projections) and the formation of blebs and blisters which break away from the cell. The process is at an early stage here; no damage is visible yet. Killer" cells of the immune system attack foreign invaders and cancers. Magnification: x4500 at 6x7cm size. Magnification; x4500 at 5x7cm size."