A cell membrane antigen expressed by both human breast carcinoma cells and normal human trophoblast.

Immunohistological studies on frozen sections of human placentae and breast carcinoma tissue using heteroantisera raised against both trophoblast microvillous plasma membrane preparations isolated from normal placentae and irradiated MCF-7 breast carcinoma cells have demonstrated a cell membrane antigen expressed by both normal human trophoblast and human breast carcinoma cells. The heteroantisera used in this study had all been previously adsorbed with immobilized human term pregnancy serum, placental alkaline phosphatase and placental ferritin preparations, as well as with human peripheral blood leucocytes. The oncoplacental membrane antigen would appear not to be represented in other normal tissues, but is represented on Jar choriocarcinoma cells and to a lesser degree on AV3 amniotic cells. Adsorption experiments have demonstrated that this antigen may not be dominant within the range of antigenic specificities of heteroantisera raised against MCF-7 cells or isolated trophoblast microvillous plasma membrane preparations.