PTGDS encodes prostaglandin D2 synthase, a lipocalin superfamily member that catalyzes the conversion of PGH2 to PGD2, a prostaglandin involved in smooth muscle regulation and platelet aggregation inhibition 1. Beyond prostaglandin metabolism, PTGDS functions as a lipid transporter, binding hydrophobic molecules including retinoids and thyroid hormones 1. In the central nervous system, PTGDS exhibits sex-specific expression patterns, with higher levels observed in female human dorsal root ganglia neurons compared to males 2. The protein demonstrates diverse roles across different pathological contexts. In diffuse large B-cell lymphoma, PTGDS promotes tumorigenesis through MYH9-mediated regulation of Wnt-β-catenin-STAT3 signaling, with N-glycosylation at Asn51 and Asn78 affecting its subcellular localization and stability 1. Conversely, PTGDS shows protective cardiovascular effects, as plasma PTGDS levels inversely correlate with exercise blood pressure responses and incident hypertension risk 3. In inflammatory conditions, PTGDS expression is upregulated in fibroblasts during rosacea development 4 and reduced in microglial cells in Parkinson's disease models with decreased neuroinflammation 5. PTGDS also serves as a diagnostic marker for sepsis and ARDS 6 and shows region-specific expression in liver fibrosis 7.