Alpha-1-B glycoprotein (A1BG) is a secreted plasma glycoprotein that functions as a modulator of sterol metabolism and an oncogenic factor in multiple cancer types. Structurally, A1BG contains five repeated immunoglobulin-like domains and localizes to extracellular regions, blood microparticles, and platelet alpha granules 1. A1BG's primary mechanism involves inhibiting sterol-binding and export functions of CRISP proteins through direct protein-protein interaction that requires magnesium coordination 1. In cancer progression, A1BG promotes chemoresistance through the A1BG/NAMPT/PARP1 axis; specifically, A1BG stabilizes NAMPT protein, increasing NAD+ production and enhancing PARP1-mediated DNA repair, thereby conferring cisplatin resistance in osteosarcoma cells 2. A1BG demonstrates bidirectional roles in cancer: while the A1BG protein is upregulated across multiple cancer types and associates with poor prognosis 1, the lncRNA A1BG-AS1 functions as a tumor suppressor in hepatocellular carcinoma through miR-216a-5p sponging 3. Conversely, A1BG-AS1 promotes adriamycin resistance in breast cancer by recruiting IGF2BP2 to stabilize ABCB1 mRNA in an m6A-dependent manner 4. Clinically, A1BG serves as a prognostic biomarker associated with tumor heterogeneity and malignancy in breast cancer 5, and elevated A1BG expression correlates with poor clinical outcomes in hepatocellular carcinoma 3. Understanding the A1BG/NAMPT/PARP1 axis offers potential therapeutic targets for overcoming obesity-associated chemoresistance 2.