FABP6 (fatty acid-binding protein 6) is a 14-15 kDa intracellular lipid chaperone that binds and transports fatty acids and bile acids, primarily expressed in intestinal epithelium, ovaries, and adrenal tissue 1. Beyond its classical role in bile acid homeostasis, FABP6 functions in lipid metabolism and immune regulation 1. Mechanistically, FABP6 regulates metabolic pathways and gene expression critical for cancer progression 1. In cancer cells, FABP6 downregulates MHC-I molecule expression to reduce CD8+ T cell infiltration, fostering immunosuppressive microenvironments 1. Conversely, FABP6 knockdown increases MHC class I expression and promotes immune-related chemokine secretion, enhancing tumor immunogenicity and CD8+ T cell recruitment 2. FABP6 inhibition also reduces tumor cell invasion and angiogenesis in glioblastoma through decreased MMP-2 and VEGF expression 3. Clinically, FABP6 expression is elevated in multiple cancers including colorectal cancer, glioblastoma, and clear cell renal carcinoma 435. Elevated serum FABP6 levels serve as an independent risk factor and diagnostic biomarker for colorectal cancer, with 83.7% sensitivity 4. Beyond cancer, FABP6 expression in ovarian granulosa cells is essential for fertility and ovulatory response 6. FABP6 represents a potential therapeutic target for combination cancer treatments and immunotherapy sensitization.