Osbp2, also known as HLM, is a member of the oxysterol-binding protein (OSBP) family. It binds specifically to oxysterols like 7-ketocholesterol and is involved in processes related to lipid metabolism, as oxysterols influence various cellular functions such as sterol metabolism, lipid trafficking, apoptosis, and cell differentiation [4]. It has been found to be associated with multiple biological pathways, potentially including WNT, MTOR, MAPK, and NOTCH signaling pathways [1].

Osbp2 has been implicated in several diseases. In hepatocellular carcinoma (HCC), its overexpression is related to poor prognosis, immunotherapy resistance, and chemotherapy resistance. It can inhibit NK cell and TIL cell infiltration, and impair Type-I and II IFN responses [1]. In pancreatic ductal adenocarcinoma (PDAC), overexpression of Osbp2 promotes cell migration, invasion, proliferation, and chemotherapy resistance, and decreases apoptosis, potentially through epithelial-mesenchymal transition [3]. In opisthorchiasis-associated cholangiocarcinoma, it may serve as a molecular marker for tumor metastasis [6]. In chronic myeloid leukemia, it is expressed in a significant proportion of patients, suggesting a role in disease monitoring [2]. In age-related macular degeneration, allelic variants of Osbp2 gene may be involved in the pathogenesis of oxidative damage to the macula [9]. In ITP, its expression is lower in patients compared to normal subjects, and it may be used as an effective diagnostic biomarker [8]. In Pekin ducks, differential expression of Osbp2 between susceptible and resistant lines to DHAV-3 infection is associated with altered lipid homeostasis [5]. In Kashmir cattle, it is related to reproduction [7]. Knockdown of Osbp2 increased the anti-PV activities of minor enviroxime-like compounds in cells [10].

In conclusion, Osbp2 plays crucial roles in lipid-related cellular processes and is associated with multiple disease conditions, including various cancers, leukemia, ITP, age-related macular degeneration, and duck hepatitis A virus-3 infection in ducks. Functional studies, especially those involving loss-of-function models like knockdown in cells, have revealed its importance in disease-related biological processes, providing potential targets for therapeutic intervention.