An isothiocyanate found in cruciferous vegetables with chemopreventive and potential antitumor activities. Although the mechanism of action is unclear, phenethyl Isothiocyanate (PEITC) was shown to induce apoptosis in tumor cells, possibly mediated through its metabolic intermediates, reactive oxygen species (ROS). PEITC also is able to activate ERK and JNK signal transduction, which in turn induces expression of stress-responsive genes. Specifically, this agent has been shown to reactivate gene expression of a detoxification enzyme, glutathione S-transferase that is silenced in prostate carcinoma.