Test Details: Immunohistochemical testing helps to identify specific antigens (proteins) within tissue sections utilizing an antigen-specific antibody. Placental alkaline phosphatase (PLAP) is a membrane-associated glycoprotein primarily expressed in placental syncytiotrophoblasts from the eighth week throughout the pregnancy. PLAP is a marker for several germ cell tumours such as seminoma, dysgerminoma, embryonal carcinoma, yolk sac tumour and gonadoblastoma.