Anti-EPPIN antibodies are used in the immunodetection of the protein epididymal peptidase inhibitor. In humans, the canonical protein has a reported length of 133 amino acid residues and a mass of 15.3 kDa. It has been described to be a secreted protein. Up to 3 different isoforms have been reported for this protein. It is notably expressed in the testis. EPPIN is a type of serine protease inhibitor that plays an essential role in male reproduction and fertility. Synonyms for this target antigen include cancer/testis antigen 71, cancer/testis antigen 72, epididymal protease inhibitor, epididymis secretory sperm binding protein, protease inhibitor WAP7, and WAP four-disulfide core domain protein 7. Western Blot, Immunofluorescence, and Immunohistochemistry are common applications for EPPIN antibodies.