ADH1A and hepatocellular carcinoma: Furthermore, this study identified PYCR2 (a crucial enzyme in proline biosynthesis) and ADH1A (enzyme metabolizing a wide variety of zenobiotic compounds) as prognostic biomarkers (confirmed by multivariate analysis: PYCR2 high versus low, HR 1.792; ADH1A low versus high, HR 2.703) involved in HCC metabolic reprogramming [78].