NRF1 and hepatocellular carcinoma: First of all, transcription activator-like effector nucleases (TALENs)-directed frameshift mutation into the genomic Nrf1 sequence is allowed for site-specific deletion of Nrf1α, but not of other smaller isoforms including Nrf1β/γ, in the human hepatocellular carcinoma (HepG2) cells, followed by selection of the homozygous knockout (Nrf1α−/−) monoclonal cells.