Clinical evaluation of ovarian tumor antigen NB/70K: monoclonal antibody assays for distinguishing ovarian cancer from other gynecologic disease.

Circulating human ovarian tumor antigen NB/70K levels were assessed with four monoclonal antibody radioimmunoassays. A total of 844 blood samples from patients with ovarian cancer and gynecologic control subjects was evaluated to determine the specificity of each of the four assays for ovarian cancer. It was determined that the mean and percent positivity for patients with ovarian cancer were significantly higher than those values for all control groups. When clinical parameters of the patients with ovarian cancer were examined, it was found that NB/70K appeared to be elevated in patients with all of the pathologic types of early stage, low-grade epithelial ovarian cancers studied. One of the four radioimmunoassays (the NB12123 assay) was capable of detecting elevated blood NB/70K levels in greater than 50% of patients with early stage ovarian malignancies. The NB12123 assay was also able to detect NB/70K in the blood of 45% (9 of 20) of patients with stage I, well-differentiated ovarian cancer. These results indicate that NB/70K may be a useful marker for the early detection of localized tumors as well as for monitoring patients with ovarian cancer, as has been demonstrated previously. In addition, NB/70K appears to be a marker for all stages, grades, and pathologic types of human ovarian epithelial tumors.