Cerebrospinal fluid placental alkaline phosphatase in the intracranial germinomas: results of enzyme antigen immunoassay.

The authors investigated the placental alkaline phosphatase (PALP) activity in cerebrospinal fluid (CSF) by enzyme-antigen immunoassay using polyclonal antibody as a marker for intracranial germinomas in 17 patients with germ cell tumors and 20 with other disorders. The detection limit of PALP activity was 0.072 optical density units equivalent to 5.9 ng/ml. Five of nine germinomas demonstrated high CSF PALP activities before treatment. These high PALP activities became undetectable following radiation therapy. The other tumors were small or had no CSF contact. CSF PALP activity is a useful tumor marker for pure germinomas.