Survivin is a newly described apoptosis inhibitor that is expressed in many human cancers, but undetectable in terminally differentiated adult tissues. It has been shown that recombinant expression of Survivin conteracts apoptosis of B lymphocyte precursors deprived of interleukin 3 (IL-3), sμggesting a potential role of Survivin in cancer therapy. Survivin interacts with the processed form of caspase-3 and inhibits its proteolytic activity.