The evaluation of CA54/61 in the diagnosis of ovarian cancer--with special reference to the cooperative results of 5 institutes]

The clinical usefulness of a newly developed one-step enzyme-immunoassay, MKS-15, in the diagnosis of ovarian cancer was evaluated with 1,563 serum samples collected at five institutes. In this assay, two monoclonal antibodies, MA54 and MA61, which both recognize the carbohydrate chain in a high molecular weight mucin-type glycoprotein, were used as the immobilized antibody on beads and peroxidase-labeled antibody, respectively. When the cut-off value was set at 20 IU/ml (mean + 3SD), 56% of the sera from ovarian cancer patients were positive, and the positive rates for serous, mucinous, mesonephroid, endometrioid, undifferentiated, and metastatic cancers were 63%, 55%, 52%, 38%, 55%, and 62%, respectively. In sera from patients with benign ovarian tumors, only 4% of the cases were positive, but 7% of benign and low potential malignant cases of mucinous cystadenoma were positive, indicating that CA54/61 cannot distinguish benign mucinous cystadenoma from malignant ones. Since the positive rate for CA125 is rather low in mucinous cyst-adenocarcinoma, CA54/61 may be of clinical value.