CHARACTERISTIC MUCINOUS OVARIAN-CANCER ANTIGEN IS EXPRESSED IN MALIGNANTLY TRANSFORMED BLOOMS SYNDROME CELLS

Using a double-antibody panning procedure, we separated a unique cance r antigen cell line (BS-SHI-4M OVC-MU) expressing a mucinous ovarian c ancer (OVC) antigen from a malignantly transformed Bloom's syndrome ce ll line. In order to gain information concerning a mucinous OVC antige n, we tested this unique cell line in the reaction to sera from patien ts with various OVCs, Krukenberg (KR) tumor, and signet ring cell canc er of the stomach under immunofluorescence and Western blotting protoc ols and determined the mucinous OVC antigen band at M(r) 84,000. We al so undertook an immune electron microscopic study to gain information concerning the antigen-antibody reaction [BS-SHI-4M OVC-MU cells-sera from patients with mucinous OVC and KR tumor] and concerning the antig enic determinant of the membrane using preembedding methods. Occasiona l protein A-gold particles were observed along the cell membrane of BS -SHI-4M OVC-MU cells, when treated with sera from mucinous OVC and KR tumor patients, but no labeling was observed in the cell membrane when treated with sera from normal patients and those with other cancers. Results of the immune electron microscopic study strongly support the data from the antigen-antibody reaction obtained by immunofluorescence and Western blotting analyses. The BS-SHI-4M OVC-MU cells separated h ere would be useful for serodiagnosis of mucinous OVC and KR tumors an d for follow-up of patients after therapy.