Abstract: The sections of human placenta were examined for the localization of the tumor-associated placental proteins(PP)by using mean of an indirect,peroxidase-labeled antibody procedure. Placental tissue section that were exposed to the antisera of the PPshowed a marked staining of the trophoblast plasma membrane. Additionally,the specific antisera of the PPalso stained the human liver carcinoma cell line(SMMC-7721)and the gastic carcinoma cell lines(MGC-803,Kato-111),suggesting these cell lines synthesize the proteins that similar to PPantigenically.

Key words: placental protein, trophoblast, tumor-associated antigen