MEP1A encodes the alpha subunit of meprin A, a metalloendopeptidase localized to chromosome 6 1. The gene spans approximately 45 kb with 14 exons and is expressed in a tissue-specific manner primarily in kidney, appendix, colon, and small intestine 1. MEP1A functions as a metalloendopeptidase with broad proteolytic activity, modulating signaling receptor ligand precursor processing and regulating inflammatory cytokine activity 2. In disease contexts, MEP1A upregulation associates with poor clinical outcomes in hepatocellular carcinoma (HCC) and colorectal cancer (CRC), serving as an independent prognostic predictor 3 4. Elevated MEP1A expression correlates with increased tumor cell proliferation, migration, invasion, and epithelial-mesenchymal transition in cancer models 3 4. Beyond malignancy, MEP1A promotes abdominal aortic aneurysm (AAA) formation by enhancing TNF-α secretion from mast cells, which subsequently increases matrix metalloproteinase expression and smooth muscle cell apoptosis 2. MEP1A deletion significantly reduces AAA progression and improves survival in mouse models 2. Additionally, rare MEP1A polymorphisms show potential association with migraine susceptibility in familial cases 5. These findings establish MEP1A as a multifunctional protease with significant implications for cancer prognosis and vascular disease pathophysiology.