DHCR24 (24-dehydrocholesterol reductase) catalyzes the final step of cholesterol biosynthesis by reducing the delta-24 double bond of desmosterol to cholesterol 1. Beyond its canonical enzymatic function, DHCR24 exhibits pleiotropic roles in cellular homeostasis and disease pathogenesis. The enzyme protects cells from oxidative stress-induced apoptosis and amyloid-beta toxicity through mechanisms independent of cholesterol synthesis 2. Dysregulation of DHCR24 is implicated in multiple pathologies: reduced brain DHCR24 activity correlates with Alzheimer's disease pathogenesis through cholesterol deficiency and lipid raft disorganization 3; elevated DHCR24 expression drives melanoma metastasis and cancer progression via oxidative stress resistance and metabolic reprogramming 24; and DHCR24 acetylation at Lys254 promotes hepatocellular carcinoma through 7-ketocholesterol/p62 axis activation 5. DHCR24 also mediates bladder cancer lymphatic metastasis through SUMOylation-driven translational control of TBK1 6. Therapeutically, DHCR24 inhibition accumulates desmosterol, activating LXRα to ameliorate fatty liver disease and inflammation 7. These findings establish DHCR24 as a metabolic hub integrating cholesterol synthesis with cell survival signaling and oncogenic pathways.