[Heterogeneity of CA 125 antigens released from human endometrial heterotopic epithelium and ovarian cancer].

We purified CA125 antigen from the conditioned media (CM) of eutopic and heterotopic endometrial epithelial cells (EC) as well as ovarian cancer cell lines, SHIN-3 and HOC-I, to determine what molecular weight forms of CA125 antigen were identifiable. Treatment of the high-molecular-weight CA125 antigen with 6M urea yielded a much lower molecular mass peak. After purification by OC125 affinity column chromatography, samples were applied to 3 to 7% polyacrylamide gradient gel and analyzed by Western blot. A single band with a molecular weight (MW) of 200KDa was identified in eutopic EC materials. The CA125 polypeptide of the 110KDa molecule could be detected in all of the CM obtained from heterotopic EC, irrespective of the length of time in the cell culture. A MW of approximately 200 KDa was also observed in some heterotopic EC samples. On the other hand, although the multiple bands with a MW equal to orless than 200KDa were observed in the CM of two ovarian cancer cells, the CA125 polypeptide of 110KDa molecules could not be detected. This preliminary finding offers promise that the 110KDa molecule detection method may be a useful adjunct in the differential diagnosis of heterotopic EC and ovarian cancer.