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PLAP

Tuesday 14 March 2006

Placental alkaline phosphatase

The evolution of the gonads during intra-uterine development has been followed by immunohistochemical demonstration of placental-like alkaline phosphatase (PLAP) at the germ-cell level.

PLAP immunopositivity was restricted to the limited period when germ cells were not surrounded by granulosa or Sertoli cells.

Abnormal fetuses or neonates presenting with chromosomal anomalies frequently had disorganized gonads where germ cells retained their membrane PLAP immunopositivity.

This abnormal immunopositivity is similar to that expressed by abnormal germ cells in testicular in situ carcinoma, in gonadoblastoma (case of 45,XO/46,XY mosaic) and in seminoma.

The pattern of positivity for other germ-cell tumours was highly variable.

In abnormal gonads, dysgenetic or neoplastic, an early embryonic property is retained by abnormal germ cells.

References

- Bailey D, Marks A, Stratis M, Baumal R. Immunohistochemical staining of germ cell tumors and intratubular malignant germ cells of the testis using antibody to placental alkaline phosphatase and a monoclonal anti-seminoma antibody. Mod Pathol. 1991 Mar;4(2):167-71. PMID: 1646453

- Loftus BM, Gilmartin LG, O’Brien MJ, Carney DN, Dervan PA. Intratubular germ cell neoplasia of the testis: identification by placental alkaline phosphatase immunostaining and argyrophilic nucleolar organizer region quantification. Hum Pathol. 1990 Sep;21(9):941-8. PMID: 1697556

- Placental alkaline phosphatase in developing normal and abnormal gonads and in germ-cell tumours. Hustin J, Gillerot Y, Collette J, Franchimont P. Virchows Arch A Pathol Anat Histopathol. 1990;417(1):67-72. PMID: 1972819

- Burke AP, Mostofi FK. Intratubular malignant germ cells in testicular biopsies: clinical course and identification by staining for placental alkaline phosphatase. Mod Pathol. 1988 Nov;1(6):475-9. PMID: 2851788

- Burke AP, Mostofi FK. Placental alkaline phosphatase immunohistochemistry of intratubular malignant germ cells and associated testicular germ cell tumors. Hum Pathol. 1988 Jun;19(6):663-70. PMID: 2837430

- Manivel JC, Jessurun J, Wick MR, Dehner LP. Placental alkaline phosphatase immunoreactivity in testicular germ-cell neoplasms. Am J Surg Pathol. 1987 Jan;11(1):21-9. PMID: 3538918