Clinical usefulness of serum sialyl SSEA-1 antigen levels in patients with epithelial ovarian cancer. Comparative effectiveness of sialyl SSEA-1 and CA 125

The serum levels of sialyl SSEA-1 antigen, a type 2 chain carbohydrate antigen detected using the monoclonal antibody FH-6, were elevated in 47.2% of patients with epithelial ovarian cancer, with the percent positivity increasing with the clinical stage. Of the histological type, it is interesting to note the relatively high sensitivity in patients with mucinous adenocarcinoma and clear cell carcinoma in contrast with the CA 125 antigen levels. Although the percentage of patients with ovarian cancer who had elevated sialyl SSEA-1 antigen levels is lower than that observed with elevated CA 125 antigen levels, the false-positive rate is significantly low in the sialyl SSEA-1 test. Serial sialyl SSEA-1 antigen levels obtained during follow-up were strong predictors of clinical outcome. The combined determination possible with sialyl SSEA-1 and CA 125 did not markedly increase the detection rate because of the overlap in the positivity. However, increased levels of both serum sialyl SSEA-1 antigen and CA 125 antigen indicated the presence of malignancies in pregnant women associated with ovarian tumors.