High NQO1 activity and expression are seen in many human tumors, including carcinoma of the liver [51], [52], colon [53], breast [52], [54], brain [55], and lung [52], and NQO1 has been shown to be an important factor in β-lapachone-induced cell death in many kinds of cancer cells [9], [44], including breast cancer [2], glioma [56], and prostate cancer [44]. Here, NQO1 is linked to prostate cancer.