ADAM18 is a sperm surface membrane protein involved in male reproductive function. As a non-catalytic metalloprotease-like protein 1, ADAM18 is expressed exclusively or abundantly on mammalian sperm and contains a putative integrin-binding ECD motif 2, suggesting a role in oocyte recognition during fertilization. The protein is identified in the Rhesus macaque sperm proteome as one of three ADAM family members with potential functions in spermatogenesis and fertilization 1, though notably ADAM18 represents a gene subsequently lost in the human lineage 3. Despite human ADAM18 containing an uninterrupted open reading frame and producing mature protein on human sperm 2, its functional significance in human reproduction remains incompletely characterized. Beyond reproductive contexts, ADAM18 has been identified as a component of matrix metalloproteinase-related prognostic signatures in hepatocellular carcinoma 4 and as a novel biomarker in diabetic retinopathy pathogenesis 5, suggesting broader roles in disease-relevant proteolytic and inflammatory processes. Additionally, ADAM18 mutations have been identified in uterine leiomyomas, implicating it in cell-to-cell interactions and extracellular matrix remodeling 6. The protein is significantly downregulated in fetal growth restriction contexts, indicating involvement in prenatal brain development 7.