Specific Immunoassays for Placental Alkaline Phosphatase As a Tumor Marker

[摘要] Human placental (hPLAP) and germ cell (PLAP-like) alkalinephosphatases are polymorphic and heat-stable enzymes. This studywas designed to develop specific immunoassays for quantifyinghPLAP and PLAP-like enzyme activity (EA) in sera of cancerpatients, pregnant women, or smokers. Polyclonal sheep anti-hPLAPantibodies were purified by affinity chromatography with wholehPLAP protein (ICA-PLAP assay) or a synthetic peptide (aa 57–71)of hPLAP (ICA-PEP assay); the working range was0.1–11U/L and cutoff value was0.2U/L EA for nonsmokers. Theintra- and interassay coefficients of variation were3.7%–6.5% (ICA-PLAP assay) and9.0%–9.9% (ICA-PEP assay). Aninsignificant cross-reactivity was noted for high levels ofunheated intestinal alkaline phosphatase in ICA-PEP assay. Apositive correlation between the regression of tumor size and EAwas noted in a child with embryonal carcinoma. It can be concludedthat ICA-PEP assay is more specific than ICA-PLAP, which is stilluseful to detect other PLAP/PLAP-like phenotypes.

[学科分类] 基础医学