Treatment with anticancer drugs sets into motion a morphologically and
biochemically distinct type of cell death called apoptosis. Recent ge
netic and biochemical studies have suggested that proteases play a pro
minent role in the active phase of apoptotic cell death. Ongoing studi
es are aimed at identifying the proteases involved, the substrates tha
t are cleaved, and the means by which the proteolytic process is regul
ated in nonapoptotic and apoptotic cells. The possibility that these f
indings will suggest new approaches to treating cancer and other disea
ses is discussed.