NQO1 and neoplasm: Mitomycin C is not an active chemotherapeutic agent de novo, but requires reductive activation via upregulated enzymes (e.g., DT-diaphorase or NQ01) in tumor cells.20,21 Most gastrointestinal malignancies have upregulation of these enzymes and, as a result, are susceptible to mitomycin C. However, in patients with recurrent disease, mitomycin C may have been ineffective during the initial HIPEC owing to low levels of enzyme activity in that the tumor.