Tumor antigen NB/70K and CA 125 levels in the blood of preoperative ovarian cancer patients and controls: a preliminary report of the use of the NB12123 and CA 125 radioimmunoassays alone and in combination.

The NB12123 and CA125 radioimmunoassays, murine monoclonal antibody assays for measuring circulating levels of human ovarian tumor associated antigens NB/70K and CA 125, respectively, have been previously described. In the present study, preoperative serum samples were obtained from patients undergoing laparotomy for benign neoplastic ovarian tumors (N = 16), cancer of the cervix (N = 22), cancer of the uterus (N = 20), and cancer of the ovary (N = 47). Controls (N = 50) were obtained from healthy blood bank donors. No correlation was observed between the levels of NB/70K and CA 125 in these samples (r2 = .079, linear regression analysis). In general, increasing levels of both antigens were present with increasing tumor burden and higher histological grade. In addition, both markers were most elevated in the serum of ovarian cancer patients with serous and unclassified adenocarcinomas. Using 40 AU and 35 unit cut-offs for the NB/70K and CA 125 assay, respectively, overall specificity for healthy controls and patients with benign diseases approaches 100%. The combined sensitivity of the assays for ovarian cancer patient sera in this study indicates that the assays may be helpful in establishing a pre operative diagnosis of ovarian cancer. Complementarity of the NB/70K and CA 125 assays has been demonstrated, indicating that one or both assays may be used to monitor as many as 85% of ovarian cancer patients.