Acetaldehyde Dehydrogenases in Liver Zonation and Liver Cancer

The liver maintains important homeostatic functions such as metabolism and detoxification. Failure to remove toxic intermediates can cause hepatic damage, liver fibrosis, and even cancer development. This review focuses on acetaldehyde dehydrogenases (ALDHs), a group of key enzymes within the ALDH superfamily with the ability to convert highly reactive aldehyde substrates to the corresponding carboxylic acids in NAD(P)-dependent manners. These enzymes participate in a diverse array of biological processes such as detoxification, biosynthesis, antioxidant, and regulatory functions. ALDH dysfunction can disrupt homeostasis, leading to toxic buildup, tissue damage, and cancer. Here, we examine the expression patterns of hepatic ALDHs in adult normal human livers and two types of liver cancers—hepatocellular carcinoma and cholangiocarcinoma. We also investigated their distributions related to liver zonation. These observations provide deep insights into previously unrecognized spatial and temporal regulation of ALDHs in liver zonation.