FADS2 (fatty acid desaturase 2) is a rate-limiting enzyme that catalyzes the delta-6 desaturation of essential polyunsaturated fatty acids (PUFA), converting linoleic acid (LA) to gamma-linolate (GLA) and alpha-linolenic acid (ALA) to stearidonate 1. This represents the critical first step in biosynthesis of highly unsaturated fatty acids (HUFA), including arachidonic acid and docosahexaenoate (DHA), which are essential for nervous system function and lipid signaling 1. FADS2 also possesses delta-8 and delta-4 desaturase activities and uniquely catalyzes production of sapienic acid from palmitate—a fatty acid component of human sebum with potential antimicrobial properties 1. In cancer biology, FADS2 dysregulation significantly impacts disease progression. High FADS2 expression in triple-negative breast cancer and ovarian cancer increases PUFA-containing phospholipid accumulation, which sensitizes cells to ferroptosis—iron-dependent lipid peroxidation 23. FADS2 lies within the frequently amplified 11q13 chr11 locus in multiple cancer types and its inhibition paradoxically impairs eicosanoid synthesis, potentially acting as a tumor suppressor in certain contexts 4. In hepatic steatosis, FADS2 enhancement increases PUFA abundance and reduces de novo lipogenesis, identifying it as a therapeutic target 5. FADS2 expression is regulated by mTOR signaling and SREBP-1 activity 6 and participates in STING-mediated metabolic control of inflammatory responses 7.