THE USE OF MUCIN-SPECIFIC MONOCLONAL-ANTIBODIES AND LECTINS IN THE DETECTION OF TUMOR-ASSOCIATED SERUM MARKERS IN GYNECOLOGICAL CANCER

The use of the mucin-specific lectin from Sambucus sieboldiana (SSAM) in the detection of tumor-associated serum antigens produced by patien ts with ovarian, cervical, and uterine cancer was investigated. Two-si te assays were developed which used either SSAM or the MUC1 core prote in-specific monoclonal antibody (mab) BC2 as capture, and biotinylated SSAM to detect bound mucin (SSAM and BC2SSAM assays respectively). Th ese new assays were compared to the CA125 assay, and another assay for MUC1 (CASA), which utilizes the core protein reactive mabs BC2 and BC 3. Some asymptomatic women and patients with benign disease showed ver y high levels in the SSAM assay, while this was not the case in the ot her assays. When cutoff levels were set to exclude healthy women and p atients with benign disease, the levels of detection in patients with ovarian cancer were 51% with CASA (>6.7 units/ml), 71% with CA125 (>25 0 units/ml), and 38% with BC2SSAM (>8.6 units/ml). The levels of detec tion in cervical and uterine cancer patients were 28% and 25% with CAS A, 0% and 8% with CA125, and 28% and 25% with BC2SSAM respectively. Of particular interest was the very different spectrum of reactivity obs erved with the CASA and BC2SSAM assays which use the same capture mab, indicating that each assay detects different glycoforms of the MUC1 m ucin. Indeed, when used in combination, the CASA and BC2SSAM assays ga ve 62% of ovarian cancer patients, and 50% of cervical or uterine canc er patients with elevated marker levels. The additional use of BC2SSAM gave no advantage over the combined use of the CASA and CA125 assays in ovarian cancer, with 80% of patients detected, but the CASA/BC2SSAM combination was particularly useful in the cervical and uterine cance rs due to the low level of detection with CA125. In fact, the addition al use of CA125 gave no advantage over the CASA/BC2SSAM combination in these patients. Furthermore, the BC2SSAM assay may also be useful in monitoring patients with high preoperative BC2SSAM levels (>10 units/m l), since this assay predicted recurrence in 5/5 cases, and was negati ve in all cases with no evidence of disease. Furthermore, the performa nce of this assay in monitoring these patients was equal or superior t o CA125 and CASA.