During early characterisation of the Nrf2-ko mouse, many small molecules that were found to require the CNC-bZIP transcription factor in order to induce Nqo1 and Gsta1 genes had already been classed as cancer chemopreventive ‘blocking’ agents because they can prevent or retard the initiation of carcinogenesis in rodents if administered prior to treatment with a chemical carcinogen [44]. The gene discussed is NFE2L2; the disease is cancer.