[The usefulness and limitation of sugar antigen in ovarian cancers--with special reference to a new tumor marker, CA54/61].

1. Two monoclonal antibodies, MA54 and MA61, were established by immunizing with culture medium supernatants of a lung adenocarcinoma cell line, and a double determinants sandwich enzyme immunoassay system (MKS-15) was developed by using these two monoclonal antibodies. The antigen recognized by this assay (CA54/61) was found in the sera of 54% of all ovarian cancer cases and 55% of mucinous cystoadenocarcinoma cases, but in 4% of benign ovarian cystoadenoma cases: 85% of ovarian cancers were positive by the combination assay of MA 54/61 and CA125, indicating the clinical usefulness of CA54/61. 2. Galactosyl transferase isozyme II (GT-II) was assayed by a newly developed system, and it was found that 74% of ovarian cancers were positive and the value GT-II was very high in 6 of 9 mesonephroid cases, indicating its histological type specificity. 3. Placental alkaline phosphatase (PLAP) was assayed by two kinds of newly developed EIA kits, and it was found that PLAP was high in more than 50% of serous cystoadenocarcinomas, but in 7% of benign ovarian tumors, indicating its cancer specificities.