[Rational application of tumor marker CA 125 in gynecological oncology]

CA 125 determination started in 1981, when Bast et al. discovered monoclonal antibody OC-125 belonging to immunoglobulin G class (IgG1) using Köhler and Milstein's technique of hybridization. CA 125 antigen is produced in amniotic cells of the 7 week-old embryo, while in adults it can be detected in epithelium of most organs which originate from Müller ducts. The upper level of referent values for CA 125 in serum is 35 U/mL and can be seen in about 99% of healthy people. APPLICATION OF TUMOR MARKER CA 125 IN GYNECOLOGICAL ONCOLOGY: More than 83% of patients with epithelial ovarian carcinoma have elevated values of CA 125 higher than 35 U/mL at the moment of diagnosing the disease. In cases of ovarian carcinoma, preoperatively determined values of CA 125 in serum are correlated with the extent of the expansion of the disease, histological type of tumor and degree of differentiation of malignant cells. Elevated values up to 65 U/mL in sernum can also be found in other malignant minors (pancreas, breast, colon, bladder, lungs, liver) and in different benign diseases. The level of serum CA 125 after the surgery can indicate regression or progression of ovarian carcinoma in more than 90% of the patients who had had elevated values of CA125 prior to the surgery. Postoperative levels of CA 125 >35 U/ mL in patients with no residual tumor and values >65 U/mL in those with residual tumor implants represent a separate prognostic factor in further course of the disease.

The importance of continuous determination of CA 125 tumor marker has to be adjusted to each single case.