Indeed, the most potent way to reduce the efficiency of apoptosis experimentally in HeLa cells (i.e. increase tswitch or reduce fPARP) and generate “half-dead” cells, appears to be to interfere with the levels or activity of XIAP [23]; the same is true in HCT116 human colon carcinoma cells [34]. Here, XIAP is linked to colon carcinoma.