Reactivity of two monoclonal antibodies (Troma 1 and CAM 5.2) on human tissue sections: analysis of their usefulness as a histological trophoblast marker in normal pregnancy and trophoblastic disease.

In normal and molar pregnancy, a morphological discrimination between nonvillous trophoblasts which lie scattered in the placental bed and surrounding maternal cells is considered to be difficult. We examined the reactivity of two monoclonal antibodies (Troma 1 and CAM 5.2) against cytokeratin by an immunoperoxidase technique and analyzed their usefulness as a histological trophoblast marker. Materials were taken from 42 uteri with normal pregnancy, 7 uteri with hydatidiform mole, 2 uteri with gestational choriocarcinoma, 1 fallopian tube with nongestational choriocarcinoma, 5 delivered term placentae of normal pregnancy, and 5 nongestational uteri. The reactivities of Troma 1 on frozen sections and those of CAM 5.2 on paraffin sections were identical. They reacted with surface epithelium and gland epithelium in the nongestational uterine corpus. In the implantation site of normal and molar pregnancy, they reacted with villous and nonvillous trophoblasts as well as endometrial gland epithelium. In gestational and nongestational choriocarcinoma, they reacted with carcinoma cells specifically. Since the histological detection of gland epithelium may not be difficult, it was concluded that the two antibodies were very beneficial as a histological marker for trophoblasts in normal pregnancy and trophoblastic disease.