Detection of oncomodulin, an oncodevelopmental protein in human placenta and choriocarcinoma cell lines.

Oncomodulin was detected by immunocytochemical means in human placenta and found to occur in the cytotrophoblastic shell during implantation, in Langhans type villar cytotrophoblastic cells, and in extravillar cytotrophoblast or intermediate trophoblast. The presence of oncomodulin during first and early second trimester was confirmed by immunoradiometric assay (IRMA). In term placenta oncomodulin appeared in intermediate trophoblast cells, and was largely absent from the villi which lack cytotrophoblast. Furthermore, oncomodulin was abundant in the choriocarcinoma cell line BeWo, and detectable in JAR but not JEG-3. The function of this oncodevelopmental calcium-binding protein in normal development or in neoplasia is not known.