[Analysis of CA 125 assay system and its diagnostic significance in gynecologic tumors]

CA125 antigen levels were measured in patients with ovarian cancer (54 cases) by the RIA method using a monoclonal antibody OC125 and were examined as a marker for ovarian cancer. The upper normal limit of CA125 of 35 U/ml was derived from the mean value (15.7 U/ml)+2SD (9.3 U/ml) of CA125 in healthy controls. The mean value for CA125 in patients with ovarian cancer (1160 +/- 1850 U/ml) was statistically (p less than 0.001) higher than those of healthy controls, benign ovarian tumors (28 +/- 20 U/ml) and cervical cancers (226 +/- 526 U/ml). Elevated CA125 levels were also found in the early pregnant stage and endometriosis, but these cases showed not so high CA125 values as those of ovarian cancers. In addition, CA125 levels were not clearly affected by the menstrual cycle. Among ovarian malignancies, the elevated CA125 values were specifically demonstrated in serous cystadenocarcinoma (positivity 89%) and markedly low in mucinous cystadenocarcinoma (positivity 16%). No positive correlation of CA125 values with the clinical stage (FIGO) were found in any ovarian cancer patients. The rise and fall of CA125 levels corresponded closely with progression and regression of cancer patients with positive CA125 levels. In conclusion, serum CA125 determinations may be useful in patients with ovarian cancer (except for mucinous type) for diagnosis and for monitoring the results of the treatment.