ALDH1A1 (ALDH1) is an aldehyde dehydrogenase and is involved in alcohol metabolism in the liver. It also plays a role in retinol metabolism, converting or oxidizing retinaldehyde to retinoic acid, and it is thought to modulate metabolic responses to a high-fat diet. ALDH1A1 is overexpressed in various cancers, and it is associated with worse prognosis in lung cancer, esophageal squamous cell carcinoma, breast cancer, and stomach cancer, and also chemo-resistance in ovarian cancer. In immunohistochemistry of normal tissue, ALDH1A1 has secreted and cytoplasmic positivity in various tissues including the liver, gallbladder, gastrointestinal tissue, kidney, thyroid, lung, reproductive tissues, adipose tissue, and brain. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804; FASEB J. 2017 Jan; 31(1): 203–211, PMID: 27729412; Oncotarget. 2016 Mar 8; 7(10): 11018–11032, PMID: 26783961