HMOX1 and digestive system cancer: Melatonin down-regulates Beclin-1 and p62 expressions and LC3B-II/LC3B-I ratio in colitis-associated colon carcinogenesis in mice; this effect is associated with the increased level of Nrf2 and its downstream antioxidant enzymes including NAD(P)H:quinone oxidoreductase (NQO-1) and heme oxygenase-1 (HO-1).