Alkaline phosphatases are phosphodiesterases. The placental-specific isozyme of Alkaline Phosphatase (PLAP) is found in trophoblast cells of normal human mature placenta, seminomas of testis and ovarian carcinomas. Detection of alkaline phosphatase in serum is a marker for ovarian and testicular cancer. This antibody reacts with a membrane-bound isoenzyme of placental alkaline phosphatase (PLAP) occurring in the placenta during the 3rd trimester of gestation. It is useful in the identification of testicular germ cell tumors. Unlike germ cell tumors, PLAP-positive somatic cell tumors uniformly express epithelial membrane antigen (EMA).
