Carcinoembryonic antigen and beta 2-microglobulin as serum tumor markers in women with genital cancer

Human epithelial-type ovarian tumour marker beta-2-microglobulin is regulated by the TGF-β signaling pathway

Background

Beta-2-microglobulin (B2M), a light chain subunit of the major histocompatibility complex (MHC) class I complex, has been implicated in tumorigenesis. However, whether it is expressed in different epithelial-type ovarian tumours remains unknown. This study was performed to examine the expression of B2M in different histopathological types of ovarian tumours, to explore the function of B2M in ovarian cancer (OC) cells and to investigate the mechanisms underlying the regulation of B2M by the TGF-β signaling pathway.

Methods

B2M expression in normal ovarian tissues and epithelia-type ovarian tumours was detected by immunohistochemistry and Western blot, followed by the analysis of association with clinical features. OC cells were transfected with B2M-siRNA and cell proliferation, migration and invasion were determined by WST-1 assay, wound healing assay and Transwell invasion assay, respectively. The regulation of B2M by the TGF-β signaling pathway in OC cells was examined by Western blot, ELISA and qRT-PCR.

Results

We found that B2M was overexpressed in ovarian borderline and malignant tumours compared with benign tumours and normal controls, but was not associated with age, tumour size, lymph node metastasis and clinical stage. Knocking down of B2M led to a decrease in OC cell proliferation, migration and invasion. The expression of B2M was downregulated by TGF-β1 in OC cells, which was abolished in the presence of the inhibitor of TGF-β type I receptor.

Conclusion

Our findings suggest that B2M is a potential tissue biomarker and therapeutic target of borderline and malignant ovarian tumours and the dysregulation of B2M in these tumours may be mediated by the TGF-β signaling pathway.

Prognostic significance of pretreatment squamous cell carcinoma antigen and carcinoembryonic antigen in squamous cell carcinoma of the uterine cervix

Sixty-seven patients with squamous cell carcinoma of the uterine cervix (FIGO Stages IB2, IIA, and IIB) were reviewed to evaluate the pretreatment level of squamous cell carcinoma antigen (SCC) and carcinoembryonic antigen (CEA) which may be used to predict a subset of patients with poor prognosis. The rate of pathologic pretreatment serum level of SCC increased significantly in cases with Stage IIB compared to that of Stages IB2 and IIA (50% versus 16.3%). The rate of pathologic pretreatment serum level of CEA did not show any difference between these two groups (29.2% versus 30.2%). The 48-month disease-free survival for patients with pathologic pretreatment serum levels for one or both tumor-associated antigens (TAAs) was 40.0% versus 91.7% for patients with normal levels (log-rank test, P < 0.005) in Stages IB2 and IIA. Patients who had a pathologic pretreatment serum level for one or both TAAs showed higher incidence of lymph node metastasis than patients with normal levels (36.7% versus 10.8%). The patients who had pathologic pretreatment serum levels for both TAAs and lymph node metastasis have the poorest prognosis. The pretreatment serum levels for one or both TAAs make it possible to predict the clinical response to neoadjuvant chemotherapy consisting of cis-platinum (DDP) and 5-fluorouracil (5-FU). Our findings suggest that pretreatment of SCC in conjunction with CEA is a valuable tumor marker to predict the prognosis of squamous cell carcinoma of the uterine cervix and to foresee a clinical response to subsequent neoadjuvant chemotherapy.

Serum squamous cell carcinoma antigen in the monitoring of radiotherapy treatment response in carcinoma of the cervix

In this study, squamous cell carcinoma antigen (SCC) was detected in 96 of 157 patients with squamous cell carcinoma of the cervix and the percentage of patients with raised SCC levels increased with the stage of disease (P less than 0.01). The use of serial SCC assays and cervical biopsy histology during the course of radiotherapy to predict tumor response to irradiation was assessed. In patients who were given external irradiation before intracavitary radium, a high SCC level or the presence of viable tumor cells in the biopsy was found to be of no predictive value. However, at completion of radiotherapy, i.e., after intracavitary radium application, patients with persistently high SCC levels had a significantly higher incidence of residual tumor than patients whose SCC levels returned to normal (P less than 0.01). In 60% of patients with a persistently high SCC level, viable tumor was found in the cervical biopsy at the end of radiotherapy. On the other hand, only 5.4% of patients whose SCC level returned to normal had residual tumor.

Biochemical aids in the monitoring of patients with ovarian cancer

A study of possible biochemical markers of tumor recurrence and progression was made in 93 patients with ovarian cancer followed longitudinally for up to 2 years during treatment by moderate or aggressive chemotherapy regimens. A panel of potential indicators was tested; the combination of serum albumin, C-reactive protein, alpha 1-acid glycoprotein, and phosphohexose isomerase levels was found to provide information that is useful as an adjunct to the clinical assessment of patients with advanced disease. However, the system could not detect a small tumor burden. The level of beta 2-microglobulin may have value in those patients whose tumor is associated with an increase of this analyte (77%), but it would appear to reflect a large tumor mass. Serum CEA, carcino-placental alkaline phosphatase, transferrin, and prealbumin were not found to be helpful.

Prognostic significance of oncofetal antigens in patients with ovarian cancer

The prognostic significance of elevated oncofetal antigens, namely carcinoembryonic antigen (CEA), alphafetoprotein (AFP), and beta subunit of human chorionic gonadotrophin (beta HCG) were studied in 39 patients with cancer of the ovary. At low cut-off levels, (CEA greater than 2.5 micrograms/l, AFP greater than 5 micrograms/l, and beta HCG greater than 3 IU/l) the median survival was 21 months in patients with one or more positive markers compared to greater than 43 months in patients without markers. At high cut-off points (namely CEA greater than 10 micrograms/l, AFP greater than 10 micrograms/l and beta HCG greater than 10 IU/l), the median survival of patients having one or more positive markers was 10 months compared to greater than 46 months in patients with no markers. Using linear regression and Logrank analysis, the difference between the observed and expected death rate was significant (P less than 0.05 at low cut-off levels, and less than 0.01 at high cut-off levels). These results indicate that patients who have one or more positive oncofetal markers on presentation are likely to have a significantly worse prognosis than patients without markers. Moreover, higher levels of oncofetal markers are associated with correspondingly worse prognosis.

Oncofoetal antigens in cancer of the cervix and ovary

The incidence of oncofoetal antigens has been reported to be increased in patients with gynaecological cancers. In this study the incidence of CEA, AFP, and hCG (beta subunit) were studied in patients with adenocarcinoma of the ovary, adenocarcinoma of the cervix, and squamous-cell carcinoma of the cervix. Using a low cut-off point (CEA 2.5 microgram/l, AFP 5 microgram/l, and hCG 3 i.u./l) there is an unacceptably high proportion of control patients having one or more positive tests (42-54%) compared to cancer-bearing patients (67%). The specificity of the tests can be increased to over 95% by increasing the cut-off point to CEA 10 microgram/l, AFP 10 microgram/l, and hCG 10 i.u./l). Although this reduces the sensitivity considerably, the incidence of false positives in the control population is reduced to nil in non-cancer patients and to 2% in cancer patients tested when free of tumour, compared to 17% of patients with cancer of the ovary, 33% with adenocarcinoma of the cervix, and 6% with squamous-cell carcinoma of the cervix. Patients with adenocarcinoma of the cervix were clearly distinguishable from those with squamous-cell carcinoma of the cervix by these tests. There was also a significant correlation between AFP and hCG levels in adenocarcinoma of the cervix (r = 0.53, P less than 0.05).

Biologic markers in cancer diagnosis and treatment

We have reviewed several tumor markers that our advocates feel are now clinically useful, involve current assay technology, and are based on already available information. These include, in selected instances, estrogen receptors for breast cancer, thyrocalcitonin for medullary cancer of the thyroid, prostatic acid phosphatase for cancer of the prostate, alpha-fetoprotein for hepatocellular cancer, and carcinoembryonic antigen for monitoring colon cancer. We have considered the potential use of measurement of serum proteases and protein degradation products due to their activity as possible future areas of development, and we have explored measurement of tissue aryl hydrocarbon hydroxylase to identify populations at risk of cancer resulting from chemical carcinogenesis. It is clear that the study of tumor markers is already improving patient care in some specific areas and offers exciting potential for the future.

Comparison of serum beta 2-microglobulin and carcinoembryonic antigen (CEA) in the follow-up of breast cancer patients

Using commercially available radioimmune test kits, serial determinations of serum beta 2-microglobulin and CEA were performed in 337 patients, who had been treated for breast cancer by modified radical mastectomy and radiotherapy. The pre-therapeutic data indicated a higher incidence of pathological beta 2-microglobulin and CEA levels in patients with distant metastases than in patients with localized disease. However, this finding did not allow the conclusion of a direct complementarity of beta 2-microglobulin and CEA as tumour markers, since the group of patients with distant metastasis contained a high percentage of elderly patients who generally can be expected to have elevated beta 2-microglobulin serum concentrations. Therefore, the correlation of the clinical course of malignant disease and the incidence of relapses with the changes of serum beta 2-microglobulin and CEA concentrations was examined during the post-treatment surveillance: 7/9 cases (78%) with local recurrence and 46/73 cases (63%) with distant spread of disease were not indicated in the beta 2-microglobulin follow-up by pathologic serum concentrations, whereas in the CEA follow-up only 1/9 and 2/73 false negative indications were registered. The poor correlation suggests that serum beta 2-microglobulin is not directly tumour associated in breast cancer and does not fulfill the criteria of a tumour marker.