sentences:  Many physical observations that confirmed the induction of apoptosis by 4003 were made.For example, lysates of the 4003-treated cells showed increased levels of caspase-3-like protease activity; nuclei were observed to be condensed and chromatin was fragmented.Survivin has been a target of attention in recent years for cancer immunotherapy, as it is an antigen that is expressed mostly in cancer cells and absent in normal cells.