[Localization of tumor-associated placental protein in human placental tissue and detection in carcinoma cell lines].

Sections of human placental villi tissue and carcinoma cell lines (SMMC-7721, (MGC-803 and Kato-111; were examined using the indirect immunoperoxidase histological technique to further investigate the localization of the tumor-associated placental protein (PP) in human placental tissue and the expression of PP on carcinoma cell lines. PP was prepared from placenta in the first trimester. Placental tissue sections exposed to PP antisera showed a marked staining of the trophoblast cells, especially in syncytiotrophoblast. The strongly stained area was localized to the cell membrane of syncytiotrophoblast. In contrast, the nucleus and the cytoplasm of syncytiotrophoblast were stained weakly. The specific PP antisera also stained the carcinoma cell lines. Among different carcinoma cell lines, the degree of staining of liver carcinoma cell line (SMMC-7721) was higher than that of gastric carcinoma cell lines (MGC-803 and Kato-111). In the carcinoma cell lines the presence of antigen similar to PP suggests that oncogene (one) occur in human trophoblast cells as well as mice trophoblast cells.