Breast cancer cell spheroid treated with doxorubicin, SEM

False-coloured scanning electron micrograph of a breast tumour spheroid (cluster of cells). The spheroid has been treated with the anti-cancer drug doxorubicin. This is causing some of the cells to die (coloured yellow) through a process known as programmed cell death, or apoptosis, which is where cells effectively commit suicide in a controlled, predictable way. Healthy cells are coloured pink/violet. Cells were deposited on to a filter paper support in order to image them. This is visible in the background (grey). Diameter of the spheroid is approximately 250 micrometres.