Establishment of OVS1 and OVS2 monoclonal antibodies recognizing human ovarian mucinous cystadenocarcinoma.

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)

Differential radiosensitization of radioresistant human cancer cells by caffeine.

The effect of caffeine, the methylated xanthine, in sensitizing the lethal action of ionizing radiation in vitro was investigated in human cancer cells which were clinically known to be radioincurable. The tumor lines were hepatocellular carcinoma and colon adenocarcinoma. Plateau phase cultures, after absorbing doses of 2 Gy, survived at a rate of 56.30 per cent for colon cancer and at 66.05 per cent for liver cancer. Both lines were radiosensitized by caffeine but at different potencies. Noteworthily, hepatocellular carcinoma whilst less radiosensitive than colon adenocarcinoma was 4 times more susceptible to caffeine. The lowest effective caffeine concentration for liver cancer was 2 mM which slightly exceeded the anticipated lethal concentration in humans. Research on radiosensitizing effect of methylated xanthines on hepatoma system still remains intriguing. Future work should be pursued with the use of less toxic compounds, such as theobromine.

Immuno-histological characterization of OVS1 and OVS2 monoclonal antibodies recognizing human ovarian mucinous cystadenocarcinoma.

OVS1 and OVS2 monoclonal antibodies (MAbs) were established by fusing murine myeloma cell line NS1/1-Ag4-1 with mouse spleen cells immunized with fresh human ovarian mucinous-cystadenocarcinoma tissue. The selection of the MAbs was assayed by an immuno-histological (streptavidin-biotin) staining of the specific antigen antibody reaction localized on frozen sections of the same tumor. Other paraffin sections and established cell lines were also screened by immuno-histological staining in order to characterize the specificity and sensitivity of these two MAbs. OVS1 MAb showed 96% specificity and 67% sensitivity to mucinous cystadenocarcinoma with no cross reactions to normal tissue, benign tissue, other cancers, or any established cell lines. OVS2 MAb revealed only 8% specificity but 78% sensitivity to mucinous cystadenocarcinoma, however, a cross reaction to some normal and benign tissues or other cancers was shown. The data suggested that OVS1 and OVS2 MAbs could be used in combination to detect ovarian mucinous cystadenocarcinoma.