4--Nitroquinoline 1-oxide (also known as 4-NQO, 4NQO, 4Nqo, NQO and NQNO) is a quinoline derivative and a tumorigenic compound used in the assessment of the efficacy of diets, drugs, and procedures in the prevention and treatment of cancer in animal models. It induces DNA lesions usually corrected by nucleotide excision repair.