After endocytosis, heme-Hpx complexes induce HO1 expression in mouse hepatoma, in HL60 cells as well as in mouse primary neurons, where data showed that HO1 expression is required for Hpx-mediated cytoprotection (Alam and Smith, 1989; Alam et al., 1999). The gene discussed is HMOX1; the disease is hepatocellular carcinoma.