XPNPEP2 encodes X-prolyl aminopeptidase 2, a membrane-bound metalloprotease that catalyzes removal of penultimate prolyl residues from N-terminal peptides 1. As a key regulator of bradykinin metabolism, XPNPEP2 inactivates this vasoactive peptide through aminopeptidase P activity 1. The enzyme exists in both membrane-bound and secreted forms 2. Clinically, XPNPEP2 variants associate with multiple disorders. ACE inhibitor-induced angioedema risk correlates with the XPNPEP2 C-2399A polymorphism in a sex- and race-dependent manner, with increased angioedema risk in men carrying the A allele 3. XPNPEP2 is implicated in premature ovarian failure (POF) and diminished ovarian reserve (DOR); translocation breakpoints disrupting XPNPEP2 cause POF in women 4, and variants are identified in 12.5-29.2% of patients with POI/DOR 56. In cancer biology, XPNPEP2 expression correlates with metastatic potential. While decreased in overall prostate cancer tissue, serum XPNPEP2 levels are elevated in patients with lymph node metastasis, improving PSA-based prediction of metastasis 2. In cervical cancer, XPNPEP2 overexpression promotes invasion and migration through epithelial-mesenchymal transition, correlating with advanced stage and lymph node involvement 7.