Abstract: The expression of EGF and contents of three placental hormones in 91 malignant trophoblastic neoplasms(including 29 invasive moles, 12 metastatic invasive moles,29 choriocarcinomas,21 metastatic choriocarcinomas)were studied immunohistcohemically using a panel of antibodies against EGF,hCG,hPL and SP1.The results indicatsd that the expression of EGF was most intensive in neoplasticsyncytiotrophoblast(ST),middle in neoplastic intermediate trophoblast(IT),most faint in neoplastic cytotrophoblast(CT),There was a relationship between expresson of EGF and secretion of placental hormones in malignant trophoblastic tumors.The expression of EGF was more intensive, the secretion of hPL and SP1 were more marked.Because expression of EGF in invasive mole was more intensive than one in cboriocarcinoma(P0.1),so contents of hPL and SP1 in the former were more high than one in the latter(P0.01).According to our present and earlier studies, we consideredthat EGF played a promotive role for differentiation, proliferation and secretion of placental hormonesin malignant trophoblastic neoplasms. Finally, some question abaut expression of EGF and secretionof hCG was discussed.