CASP3 and neoplasm: We acknowledge the help of the following colleagues: Mike Walton for assistance with the p53 and p21 characterization; Gary Box and Sharon Gowan for assistance with the human tumor xenograft studies and cell and tissue preparations; Nina Perusinghe for microscopy; Jenny Titley for flow cytometry; and Manuela Graf for help in the quantitative image analysis of caspase-3 cleavage.