NQO1 and colorectal neoplasm: In in vivo experiments, Lin et al. evaluated the expression of antioxidant enzymes (i.e., NQO-1 and HO-1) on colorectal tumor fragments showing that Nrf2 was exclusively expressed in the nucleus (nNrf2) in NQO-1- and HO-1-positive tumors, while it was retained in the cytoplasm (cNrf2) in NQO-1- and HO-1-negative tissues.