CA 125 in human milk and serum

Serum CA 125 levels before, during and after treatment for endometriosis

OBJECTIVES

The aim of this study was to assess the treatment of endometriosis with a gonadotropin-releasing hormone (GnRH) agonist in terms of changes to the extent of disease and to CA 125 levels as well as to recurrence during follow-up.

METHODS

The levels of serum CA 125 were evaluated in 66 patients with endometriosis diagnosed and staged by laparoscopy according to the revised American Fertility. Society classification, who received a 6-month course of a GnRH agonist. Serum CA 125 levels were measured before, during (3 and 6 months after the initiation of therapy) and 6 months after cessation of therapy.

RESULTS

Patients with minimal and mild endometriosis had significantly higher mean pretreatment values than control subjects in the luteal phase of the cycle or than postmenopausal women (P < 0.05), but the overall mean value was still below 35 U/ml. Levels of CA 125 fell during treatment to those found in normal controls, but rose again after the end of treatment. The sensitivity and specificity of CA 125 were 75% and 83.3%, respectively, and its positive predictive value as a marker of recurrence was 46.36%.

CONCLUSION

These data suggest that CA 125 may be a reliable indicator for monitoring the efficacy of GnRH agonist treatment of endometriosis, but its value as a predictor of recurrence is low, probably due to the suppression of all CA 125 sources such as endometrium, ovaries and implants.

No evidence of the hook effect in peritoneal fluid CA 125 measurement using immunoenzymatic second generation assays: comparison with immunoradiometric assays

OBJECTIVE

To monitor the occurrence of the hook effect in measurements of peritoneal fluid CA 125 levels using two different immunoenzymatic second generation assays (ETI-II and EIA-II), and to compare these results with those obtained using the respective immunoradiometric versions of the assays (IRMA-II and ELSA-II).

STUDY DESIGN

CA 125 levels were determined in peritoneal fluid and serum samples obtained from 45 women with gynecological diseases. The assays were carried out using IRMA-II and ETI-II (Sorin Biomedica) and ELSA-II and EIA-II (CIS Bio International) assays. Occurrence of the hook effect and linearity of the assays were evaluated. Statistical analyses were performed by Wilcoxon's test and linear regression analysis.

RESULTS

Undiluted peritoneal fluids, assayed for their CA 125 content, showed falsely underestimated values of the antigen when IRMA-II and ELSA-II assays were performed. The phenomenon disappeared only at high dilutions of the sample (> 50). Conversely, immunoenzymatic ETI-II and EIA-II assays performed on undiluted peritoneal fluids did not show underestimated CA 125 values. CA 125 values obtained by immunoenzymatic assay were lower than those obtained using their respective immunoradiometric versions at a dilution of 1:100 (P < 0.001). A good correlation was observed between ELSA-II and EIA-II (r = 0.929) CA 125 values.

CONCLUSION

The EIA-II immunoenzymatic assay appears to be more suitable for CA 125 measurement in peritoneal fluid in that it is not subject to the hook effect and its results correlated well with those obtained via its immunoradiometric version.

Serum and peritoneal fluid CA-125 levels in patients with endometriosis

OBJECTIVE

To evaluate CA-125 in peritoneal fluid (PF) as an indicator of endometriosis.

DESIGN

CA-125 levels in paired serum and PF were determined by the one-step immunoradiometric assay. For peritoneal samples, high dilution of the sample (1:100) was used to avoid false low results, caused by the "hook effect" phenomenon.

PATIENTS

Forty-one women with and without endometriosis, undergoing laparoscopy or laparotomy during the follicular phase of the menstrual cycle, were selected.

SETTING

2nd Institute of Obstetrics and Gynecology, University of Rome "La Sapienza," Rome, Italy.

MAIN OUTCOME MEASURE

Peritoneal fluid CA-125 levels obtained using diluted samples were significantly higher than those found using undiluted ones.

RESULTS

CA-125 levels in PF were approximately 100 times higher than those found in paired serum, ranging from 970 to 10,636 U/mL. In patients with endometriosis, CA-125 levels in PF were significantly elevated when compared with the control group. In serum, CA-125 levels increased only in advanced stages of endometriosis.

CONCLUSIONS

The sensitivity of the CA-125 test for endometriosis in PF is greater than in serum. Therefore, the measurement of CA-125 levels in PF could be useful in the detection of early stage endometriosis, which tends to be overlooked by the CA-125 serum test.

Regulation of CA 125 production by amnion and WISH cells in culture

Amnion and human amnion-derived WISH cells release CA 125 antigen into culture medium. CA 125 output was higher in WISH cells than in amnion cells. In this study we showed that release of the antigen is regulated, with both amnion and WISH cells responding in a similar manner to the tested agents. Release of CA 125 decreased in the presence of dexamethasone (10(-6) mol/L) or cycloheximide (0.1 micrograms/ml) and increased when colchicine (0.01 micrograms/ml) was added to the culture medium. Stimulatory and inhibitory effects were more apparent after 3 days in culture. The precise mechanisms by which some of these agents (colchicine and dexamethasone) affect CA 125 release remain unknown. We propose that amnion and WISH cells in culture represent a useful model to investigate some regulatory aspects of the production of CA 125 in normal tissues.