Carcinoembryonic antigen and related molecules in normal and transformed trophoblast

Carcinoembryonic antigen (CEA, CD66e) and CEA-related cell adhesion molecules (CEACAMs) are important mediators in remodeling of diverse human tissues, and modulators of cell proliferation and differentiation. Expression by normal and transformed trophoblast of gestational trophoblastic diseases (GTDs), isolated cytotrophoblast and choriocarcinoma cell lines is presented here. Immunocyto/histochemistry of normal placenta (n=9), invasive mole (n=8), choriocarcinoma (n=7), a placental site trophoblastic tumor, cytotrophoblast in primary culture and JAr and JEG-3 cells was performed using polyclonal anti-CEA and specific monoclonal anti-CEA antibodies. Data were analyzed and scored using Mann-Whitney Test. CEA and CEA-related molecules were identified by Western blot and immunoaffinity chromatography in JAr and JEG-3 cells and extracts of 1st and 3rd trimester of pregnancy tissue and cytotrophoblast cell lysates. CEA is expressed throughout pregnancy, in first trimester predominantly in syncytiotrophoblast, but also in villous cytotrophoblast and extravillous trophoblast. Data presented here demonstrate that CEA is significantly increased in transformed trophoblast of GTDs (p<0.05). Both cytotrophoblast in primary culture and choriocarcinoma cell lines express CEA, with staining of granular deposits in JAr and cell membrane in JEG-3. The results suggest that CEA (CD66e) and other CEA-related protein(s) could be involved in trophoblast differentiation.