Phenethyl isothiocyanate (PEITC) presents in cruciferous vegetables which have been shown to decrease the risk of various types of malignancies. PEITC targets multiple proteins to suppress various cancer-promoting mechanisms such as cell proliferation, progression and metastasis. PEITC induces apoptosis in human colon cancer HT-29 cells, prostate cancer cells, and osteogenic sarcoma U-2 OS cells. Unique to prostate cancer is that PEITC downregulates the transcriptional factor Sp1, a regulator of AR expression. PEITC suppresses 4-(methylnitrosamino)-1-(3-pyridyl)-1-butoneinduced pulmonary neoplasia in A/J mouse lung, exhibits cancer chemopreventive activity in rat and reduces azoxymethane-induced colonic aberrant crypt foci formation. PEITC appears to be a promising agent for cancer therapy and is already under clinical trials for leukemia and lung cancer.