NRF1 and hepatocellular carcinoma: Besides, the transcription expression of Nrf2 was also shown to be inhibited by Nrf1, because its basal and inducible mRNA expression levels were up-regulated to varying extents in the tissue-specific Nrf1-/- mice 348, 391, as well as in human Nrf1α-/- hepatoma cells 89, 439, 440, 441.