OSBPL5 (oxysterol binding protein like 5) is a lipid transporter that mediates phospholipid countertransport between the endoplasmic reticulum and plasma membrane, specifically exchanging phosphatidylserine with phosphatidylinositol 4-phosphate (PI4P) in a mutually exclusive manner 12. The protein binds cholesterol and oxysterols and may cooperate with NPC1 to facilitate cholesterol exit from endosomes/lysosomes 34. OSBPL5 exhibits tissue-specific expression patterns and shows biallelic expression in multiple mammalian tissues 5. In disease contexts, elevated OSBPL5 expression correlates with poor prognosis in non-small cell lung cancer, where it promotes cell proliferation, migration, invasion, and epithelial-mesenchymal transition through the LMCD1-AS1/miR-526b-3p regulatory axis 6. Similarly, OSBPL5 overexpression enhances metastatic potential in lung cancer cells 7. Additionally, OSBPL5 hypomethylation has been associated with Silver-Russell Syndrome 8, and germline variants in OSBPL5 may influence breast cancer patient survival 9. Functionally, OSBPL5 regulates cholesterol transport from lysosomes to the endoplasmic reticulum, affecting autophagy and contributing to chemotherapy resistance in ovarian cancer 10.