Abstract
Plants and animals actively cause some of their own cells to die when these cells are no longer needed or if they become damaged. In his Perspective, Green discusses one way in which this process is triggered--by binding of the cell surface protein Fas to Fas ligand. In some cells, this pathway "surfaces" and becomes active upon expression of the key oncogene myc, as reported in this issue on p. [1305][1] by Hueber et al . [1]: http://www.sciencemag.org/cgi/content/short/278/5341/1305