However, some studies have shown that the survival and development of cancer cells were promoted through excessive expression of Nrf2 and its target genes.22 Recent data suggest that the there are different degrees of Keap1 mutations in patients with lung cancer.23 Activation of Nrf2 can promote cell tumourigenicity, and knockdown of Nrf2 can inhibit tumour growth, metastasis and invasion.24 The target genes of Nrf2 are vital in tumour metastasis. This evidence concerns the gene KEAP1 and lung carcinoma.