HMOX1 and neuroblastoma: Similarly, the drastic decrease of heme oxygenase-1 (HO-1; Nrf2-regulated downstream gene) expression in the presence of NAC implicated that its antioxidant activity was effective enough to modulate the cellular redox balance apart from that of the enzymatic antioxidants produced by the Nrf2/HO-1 pathway in bilirubin-induced oxidative stress state of neuroblastoma cells [40,41].