ASAP2 (ArfGAP with SH3 domain, ankyrin repeat and PH domain 2) functions as a GTPase-activating protein that regulates vesicular transport, cellular migration, and autophagy 1. The protein activates small GTPases ARF1, ARF5, and ARF6, modulating post-Golgi vesicle formation and constitutive secretion. ASAP2 is a primary target gene of 1,25-dihydroxyvitamin D3 in human monocytes and macrophages, where it promotes RAC1 activity and macrophage efferocytosis 2. The gene contains three VDR binding sites downstream of its transcription start site, allowing vitamin D-mediated transcriptional regulation 1. In disease contexts, ASAP2 shows significant pathological relevance. It functions as a novel driver gene in pancreatic ductal adenocarcinoma, promoting tumor growth through EGFR phosphorylation, with overexpression correlating with poor prognosis 3. Circular RNA forms of ASAP2 regulate drug resistance in gastric cancer and inflammation in diabetic nephropathy 45. Additionally, rare coding variants in ASAP2 contribute to microcephaly in neurodevelopmental disorders, with functional studies demonstrating its essential role in neural progenitor cell proliferation and brain development 6. The gene represents a potential therapeutic target, with repositioned drugs like niclosamide showing anti-tumor effects through ASAP2 pathway inhibition 3.