FABP4 (fatty acid binding protein 4) is a lipid transport protein that serves as an intracellular chaperone for fatty acids and other hydrophobic ligands 1. The protein facilitates lipid metabolism by mediating fatty acid uptake and regulating mitochondrial stability and CPT1-mediated fatty acid oxidation processes 2. Beyond its intracellular functions, FABP4 undergoes regulated vesicular secretion and acts as a circulating hormone with crucial roles in systemic metabolism 3. FABP4 is highly expressed in various pathological conditions, including idiopathic pulmonary fibrosis where FABP4-expressing macrophages contribute to disease progression 4. In cancer, FABP4 promotes metastasis by enabling cancer cells to adapt to lipid-rich tumor microenvironments, particularly in ovarian cancer where it facilitates omental metastasis and mediates carboplatin resistance 56. The protein also drives triple-negative breast cancer progression and breast cancer stem cell activity through lipid metabolism regulation 2. FABP4 serves as a reliable aging biomarker, with elevated levels associated with metabolic disorders in elderly populations 7. Therapeutic targeting of FABP4 through small molecule inhibitors like BMS309403 shows promise for treating metabolic diseases, cancer metastasis, bone resorption in postmenopausal osteoporosis, and age-related metabolic dysfunction 857.