Mutant p53 upregulates Nrf2 (nuclear factor erythroid 2 –related factor 2, a transcription factor coding for detoxification enzymes and conferring resistance to anticancer drugs) in non-small cell lung cancer by increased binding to the Nrf2 promoter supported by an activation of the NF-κB signaling pathway leading to additional enhancement of Nrf2 expression. Furthermore, loss of DNA mismatch repair favors cisplatin resistance in p53 mutant colon carcinoma cells. The gene discussed is TP53; the disease is non-small cell lung carcinoma.