[The significance of serum leucine aminopeptidase (P-LAP) determination in the gynecological malignancies].
We determined Placental-Leucine Aminopeptidase (P-LAP) activity, one of the oncodevelopmental antigens, in sera and in tissues of patients with gynecological cancers. The incidence of P-LAP activity and clinical usefulness of the determination of serum P-LAP activity were studied. The mean level in healthy non-pregnant sera used as controls was 6.0 +/- 2.4mg/dl/h. The mean level of P-LAP activity in patients with benign tumors such as myoma uteri and benign ovarian tumor did not increase in comparison with the controls. The mean level of P-LAP activity in patients with malignant tumor increased with advancing stages, and especially in advanced cervical and ovarian cancer, serum P-LAP levels were significantly higher than in the controls. Serum P-LAP activity correlated with the serum ferritin concentration (r=0.613), but not with the serum alpha-fetoprotein and serum carcinoembryonic antigen concentration. Serial measurements of serum P-LAP activities in patients with gynecological cancer showed that serum P-LAP activity might reflect the progress of cervical and ovarian cancer. Tissue P-LAP activities in 29 ovarian cancers were compared with those in normal tissues. Tissue P-LAP activities in 26 cases out of 29 increased to twice as high as the mean activities in 10 normal ovaries. Our present results suggest the possibility of using P-LAP activity as one of tumor markers for gynecological malignant tumors.