NQO1 and malignant colon neoplasm: NRF2 is a helix-loop-helix basic leucine zipper transcription factor that binds to the antioxidant response element (ARE), which results in transcriptional activation of genes involved in carcinogen detoxication and attenuation of oxidative stress, such as glutathione S-transferase (GST), UDP-glucuronosyltransferase (UGT), HO-1, NQO and gamma glutamylcysteine synthetase (γGCS).(23) We showed in the present study that AHCC significantly increased HO-1 and NQO-1 mRNA levels in a dose-dependent manner in human colon cancer cells.