Moreover, chemical inhibition of cathepsin B using the selective dipeptide-derived O-benzoyl hydroxamate 3 in various highly genotoxic drug- and radiation-resistant human tumor cells likewise induced apoptosis, which is also contributing to the hypothesis on antiapoptotic survival-promoting functions of cysteine cathepsins in human cancer (Zhu and Uckun, 2000). This evidence concerns the gene CTSB and cancer.