Cellular specificity of NB70K, a putative human ovarian tumor antigen.

We have studied the cellular expression of NB/70K, a glycoprotein proposed to be human ovarian tumor associated described previously. Analysis of cells bearing this antigen in malignant ascites shows expression in tumor cells of gynecological origin (ovarian, endometrial) and to a limited degree in breast cancer cells. Within such tumors, there is a weak inverse correlation between labeling index and antigen expression. Furthermore, evidence is presented to show that the cells bearing this glycoprotein are physically separable from those bearing carcinoembryonic antigen.