HMOX1 and hepatocellular carcinoma: Some authors have reported that LPS-induced HO-1 mRNA and protein expression via activation of the transcription factor Nrf2 was independent from the ERK [38], while others have shown that HO-1 induction was via the Erk pathway in PC-12 cells treated with the phytochemical carnosol or in rat hepatoma cells treated with heavy metal arsenite [39,40].