Specialist interest article
Is placental alkaline phosphatase (PLAP) a useful marker for seminoma?

https://doi.org/10.1016/0277-5379(90)90049-YGet rights and content

Abstract

The usefulness of placental alkaline phosphatase (PLAP) as a tumour marker was assessed in 1578 serum samples from 236 patients with seminoma. Smoking habits were known for all but 7 patients (22 samples). Smoking was associated with significantly higher mean levels of PLAP in disease-free patients (28.8[S.E. 2.1]U/l vs. 15.9[1.3] U/l in non-smokers). Mean PLAP levels were higher in patients with active disease (78.6 [23.5] U/l in non-smokers and 47.2 [18.5] U/l in smokers). The median values showed a similar trend. However, there was considerable overlap between the various groups and differences between mean and median values indicated that PLAP values were distributed asymmetrically. The predictive value of PLAP as a tumour marker was consequently much less than superficial inspection of these values might suggest. In 97 patients on surveillance, only 2 out of 11 patients who relapsed had elevated PLAP at the time of clinically detectable relapse. With the upper limit of normal PLAP quoted by our laboratory (35 U/l), specificity and sensitivity were, respectively, 88% and 45% (all patients) and 96% and 47% (non-smokers). The sensitivity and specificity of PLAP were assessed in more detail for a series of threshold values (normal vs. abnormal) with a graphical method. Only in non-smokers did PLAP seem useful and even in this group the positive predictive value of an “abnormal” test may be low; less than 50% in clinically relevant circumstances. Serum PLAP assay cannot usefully stand alone as a marker for seminoma and its routine estimation contributes little to follow-up.

References (33)

  • SD Fosså et al.

    Radiotherapy for testicular seminoma stage I: Treatment results and long-term post-irradiation morbidity in 365 patients

    Int J Radiat Oncol Biol Phys

    (1989)
  • GS Lederman et al.

    Radiation therapy of seminoma: 17-year experience at the Joint Center for Radiation-Therapy

    Radiother Oncol

    (1989)
  • ME De Broe et al.

    Multicenter evaluation of human placental alkaline phosphatase as a possible tumor-associated antigen in serum

    Clin Chem

    (1988)
  • HA Muensch et al.

    Placental-like alkaline phosphatase

  • AA Epenetos et al.

    Monoclonal antibody assay of serum placental alkaline phosphatase in the monitoring of testicular tumours

    Br J Cancer

    (1985)
  • J Fisken et al.

    Serum placental-like alkaline phosphatase (PLAP): a novel combined enzyme linked immunoassay for monitoring ovarian cancer

    J Clin Pathol

    (1989)
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      Citation Excerpt :

      Serum concentrations of PLAP are increased up to 10-fold in smokers. In a Danish study assessing its value in 236 patients with seminoma, substantial overlap in serum values was seen between smokers and nonsmokers among all stages of disease, with sensitivities and specificities among all patients of 45% and 88%, respectively [18]. With this suboptimal sensitivity and specificity, as well as the limited commercial assays for PLAP, this STM is not routinely utilized in the management of GCTs.

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