Immunohistochemical localization and tissue levels of tumor-associated glycoproteins CA 125 and CA 19-9 in the decidua and fetal membranes at various gestational ages.

To investigate the sources and biologic significance of CA 125 and CA 19-9 in amniotic fluid, immunohistochemical and biochemical localization of these tumor-associated glycoproteins in the decidua and fetal membranes was studied. Immunohistochemically, CA 125 and CA 19-9 were localized in the cytoplasm of decidua cells and amnion epithelial cells but not in the chorion and placental tissue. Biochemically, the 12,000 X g supernatant fractions of decidua and amnion tissues contained relatively large amounts of CA 125 and CA 19-9, 73% to 96% of which was present in the cytosolic fractions of these tissues. The CA 125 levels in the amniotic fluid decreased, whereas those of CA 19-9 increased with gestation, which correlated well with the respective levels in amnion tissues. These findings suggest that amnion cells produce and secrete these glycoproteins into the amniotic cavity. However, it is possible that the decidua also secretes CA 125 into the amniotic cavity through the chorion and amnion such as in the case of prolactin.