CA125 and placental alkaline phosphatase as serum tumor markers in epithelial ovarian carcinoma.

Placental alkaline phosphatase (PLAP) was measured by an immunoradiometric assay using the monoclonal antibody C2 (PLAP-C2). Serum samples of 135 patients with epithelial ovarian cancer were analyzed, and the results were compared with CA125 levels. CA125 and PLAP-C2 were elevated in 85 and 43% of the patients, respectively. Only 1 patient with normal CA125 and evidence of disease at the time of sampling had an elevated PLAP-C2. Fifty-three patients with measurable tumor were followed longitudinally during chemotherapy. Correct correlation with disease evolution was observed in 95% of the patients for CA125 and in 59% for PLAP-C2. The PLAP-C2 assay did not add significantly to the predictive value of CA125 in the diagnosis and follow-up of epithelial ovarian cancer.