ABSTRACT
Two newly established murine monoclonal antibodies (MAbs), OVS1 and OVS2, to human ovarian mucinous cystadenocarcinoma were further characterized for diagnostic efficacy. The specific SA-1 antigen, purified from the tumor extract was identified as a glycoprotein of 29 kDa. A double determinant biotinstreptavidin alkaline phosphatase immunoassay system, containing OVS1 and OVS2 MAbs was used to determine the SA-1 levels in serum. The OVS1 MAb was used as a first antibody because of its high specificity of 96% while OVS2 MAb, with a lower specificity of 8% but greater sensitivity of 78%, was chosen as a second antibody. Matched sera of 64 healthy controls and 90 patients with definite diagnoses of 25 benign diseases, 14 nonovarian cancer and 51 ovarian cancer, were simultaneously measured together with CA 125 values. At cut-off levels of 220 and 360 units/ml, the SA-1 test showed 63% and 43% positive rates respectively in all types of ovarian cancer, compared to 65% and 57% positive rates for CA 125 at cut-off levels of 35 and 60 units/ml, respectively. Sensitivity for SA-1 at 220 units/ml cut-off level in mucinous ovarian cancer was 75% and increased significantly to 85% when the test was combined with CA 125 at 35 units/ml cut-off level. Furthermore, The combination of both tests significantly increased the positive rates to 86% in all types of early stage ovarian cancer.(ABSTRACT TRUNCATED AT 250 WORDS)