Preoperative serum level of inhibin A is an independent prognostic factor for the survival of postmenopausal women with epithelial ovarian carcinoma

A bioinformatic analysis of the inhibin-betaglycan-endoglin/CD105 network reveals prognostic value in multiple solid tumors

Inhibins and activins are dimeric ligands belonging to the TGFβ superfamily with emergent roles in cancer. Inhibins contain an α-subunit (INHA) and a β-subunit (either INHBA or INHBB), while activins are mainly homodimers of either βA (INHBA) or βB (INHBB) subunits. Inhibins are biomarkers in a subset of cancers and utilize the coreceptors betaglycan (TGFBR3) and endoglin (ENG) for physiological or pathological outcomes. Given the array of prior reports on inhibin, activin and the coreceptors in cancer, this study aims to provide a comprehensive analysis, assessing their functional prognostic potential in cancer using a bioinformatics approach. We identify cancer cell lines and cancer types most dependent and impacted, which included p53 mutated breast and ovarian cancers and lung adenocarcinomas. Moreover, INHA itself was dependent on TGFBR3 and ENG/CD105 in multiple cancer types. INHA, INHBA, TGFBR3, and ENG also predicted patients' response to anthracycline and taxane therapy in luminal A breast cancers. We also obtained a gene signature model that could accurately classify 96.7% of the cases based on outcomes. Lastly, we cross-compared gene correlations revealing INHA dependency to TGFBR3 or ENG influencing different pathways themselves. These results suggest that inhibins are particularly important in a subset of cancers depending on the coreceptor TGFBR3 and ENG and are of substantial prognostic value, thereby warranting further investigation.

Evolving Role of Serum Biomarkers in the Management of Ovarian Cancer

The availability of an ideal serum tumor marker would be of great clinical benefit for both the diagnosis and management of patients with epithelial ovarian cancer. Serum cancer antigen 125 assay significantly increases the diagnostic reliability of ultrasound in discriminating a malignant from a benign ovarian mass, especially in postmenopausal women, and it is the only well validated tumor marker for monitoring disease course. Several other tumor-associated antigens have been assessed, including glycoprotein antigens other than cancer antigen 125, soluble cytokeratin fragments, kallikreins, cytokines and cytokine receptors, vascular endothelial growth factor, D-dimer, and lisophosphatidic acid. This article assesses the potential diagnostic and prognostic role of these novel biomarkers, both alone and in combination with cancer antigen 125. The future for serum tumor marker research is represented by the emerging technology of proteomics, which may allow scientific advances comparable to those achieved with the introduction of monoclonal antibody technology.

Inhibin at 90: from discovery to clinical application, a historical review

When it was initially discovered in 1923, inhibin was characterized as a hypophysiotropic hormone that acts on pituitary cells to regulate pituitary hormone secretion. Ninety years later, what we know about inhibin stretches far beyond its well-established capacity to inhibit activin signaling and suppress pituitary FSH production. Inhibin is one of the major reproductive hormones involved in the regulation of folliculogenesis and steroidogenesis. Although the physiological role of inhibin as an activin antagonist in other organ systems is not as well defined as it is in the pituitary-gonadal axis, inhibin also modulates biological processes in other organs through paracrine, autocrine, and/or endocrine mechanisms. Inhibin and components of its signaling pathway are expressed in many organs. Diagnostically, inhibin is used for prenatal screening of Down syndrome as part of the quadruple test and as a biochemical marker in the assessment of ovarian reserve. In this review, we provide a comprehensive summary of our current understanding of the biological role of inhibin, its relationship with activin, its signaling mechanisms, and its potential value as a diagnostic marker for reproductive function and pregnancy-associated conditions.

Cancer progression: is inhibin alpha from Venus or Mars?

The inhibin field has been perplexed by the information that inhibin alpha is a tumour suppressor in mice yet is elevated in women with ovarian cancer. Furthermore, we have consistently observed a down-regulation or loss of inhibin alpha in prostate cancer patient samples and cell lines. However, our latest data have prompted us to re-evaluate the role of inhibin alpha in prostate and other cancers. Using the analogy of TGF-beta as a springboard for our hypothesis, we offer a unifying model whereby the previously conflicting observations in mice, men and women can be explained. We propose that initially inhibin alpha is tumour-suppressive and is expressed in benign and early-stage primary cancers. Tumour-suppressive inhibin alpha is then silenced as the tumour progresses but is reactivated as a pro-metastatic factor in advanced, aggressive cancers.

Inhibin Resistance Is Associated with Aggressive Tumorigenicity of Ovarian Cancer Cells

Malignant ovarian epithelial tumors have been shown to have decreased inhibin production relative to activin production compared with normal ovarian surface epithelial (OSE) cells and nonmalignant ovarian tumors. Activin stimulates proliferation of many ovarian cancer cell lines. Inhibin antagonizes the action of activin, and inhibin-deficient mice develop gonadal tumors, suggesting that inhibin may be a tumor suppressor. However, its effects on OSE and ovarian cancer cells are unknown. We hypothesize that activin and inhibin are important regulators of biological activity in ovarian cancers. We found that inhibin A decreased murine OSE proliferation, whereas activin A had no effect. Activin A increased the proliferation of four of eight ovarian cancer cell lines (SKOV3, OCC1, OVCAR3, and A2780-s). Inhibin A decreased the proliferation of SKOV3, A2780-s, and OVCAR3 but had no effect on OCC1, ES-2, HEY, A2780-cp, and OVCA429 cells. When injected into nude mice, the inhibin-resistant cancer cell lines resulted in shorter survival time compared with the inhibin-responsive cells. Further investigations on SKOV3 and OCC1 cells showed that activin A increased invasion through Matrigel. Inhibin A decreased both basal and activin-induced proliferation and invasion of SKOV3 but had no effect on OCC1 cells. Reverse transcription-PCR analyses showed that the SKOV3 and OCC1 cells produced activin, but only SKOV3 produced inhibin. Analysis of the activin/inhibin signaling pathways indicated that Smad anchor for receptor activation was elevated in SKOV3 and OCC1 cells and that an up-regulation of the activin receptor expression may explain the inhibin resistance of OCC1 cells. Our results suggest that activin responsiveness may be gained during transformation of OSE cells and that inhibin resistance may contribute to the aggressive behavior of ovarian cancer cells.

Serum tumor markers in the management of ovarian, endometrial and cervical cancer

CA 125 is the most reliable serum marker for ovarian carcinoma. Whereas its role in the screening of the malignancy is controversial, serum CA 125 assay is very useful for both the differential diagnosis of ovarian masses, particularly in postmenopause, and the monitoring of the response to chemotherapy and follow-up of patients with histologically proven ovarian carcinoma. Tumor-associated antigens other than CA 125, such as CA 19.9, CA 15.3 and TAG.72, firstly identified in gastro-intestinal or breast malignancies, have been detected also in tissue and serum samples from patients with ovarian carcinoma. In particular CA19.9 offers the advantage of high sensitivity for mucinous histotype, which often fails to express CA 125. Serum CA 125 correlates with the clinical course of disease better than the other antigens, and in patients with positive CA 125 assay at diagnosis the concomitant evaluation of CA 19.9 or CA 72.4 or CA 15.3 does not offer any additional benefit for monitoring ovarian carcinoma. Conversely, the serial measurements of these other antigens may represent an interesting biochemical tool for the management of patients with negative CA 125 assay. Serum alphaFP and betaHCG are very useful in the preoperative evaluation and management of nondysgerminomatous ovarian germ cell tumors, whereas elevated serum inhibin levels can be detected in patients with granulosa cell tumors of the ovary. As for endometrial carcinoma, preoperative serum CA 125 levels correlate with stage, depth of myometrial invasion, histologic grade, cervical invasion, peritoneal cytology, lymph node status and clinical outcome. Moreover, serial CA 125 assay is a good indicator of disease activity and a useful biochemical tool for post-treatment surveillance of patients with endometrial carcinoma. SCC is the most reliable serum marker for squamous cell cervical carcinoma, and in patients with this malignancy pretreatment SCC levels are related to tumor stage, tumor size, depth of cervical invasion, lymph-vascular space involvement, lymph node status and clinical outcome. Serial SCC measurements parallel the response to radiotherapy and chemotherapy as well as the clinical course of disease after the completion of treatment. Serum CYFRA 21.1 seems to be less sensitive than serum SCC for squamous cell cervical carcinoma. Elevated CA 125 levels can be often detected in patients with cervical adenocarcinoma. The future for tumor marker research is represented by the emerging technologies of transcriptional profiling and proteomics.

Expression of trypsinogen-1, trypsinogen-2, and tumor-associated trypsin inhibitor in ovarian cancer: prognostic study on tissue and serum

PURPOSE

The purpose is to study the prognostic significance of tissue expression of trypsinogen-1, trypsinogen-2, and tumor-associated trypsin inhibitor (TATI) and serum concentration of trypsinogen-2, trypsin-2-API (complex of trypsin-2 with alpha-1-proteinase inhibitor), and TATI in epithelial ovarian cancer.

EXPERIMENTAL DESIGN

Expression of trypsinogen-1, trypsinogen-2, and TATI was determined by immunohistochemistry with monoclonal antibodies in tissue sections of tumors from 119 patients with untreated primary epithelial ovarian cancer. Preoperative serum concentrations of trypsinogen-2, trypsin-2-API and TATI were analyzed using specific immunoassays.

RESULTS

Fifty-four percent of the tumors expressed trypsinogen-1, 45% expressed trypsinogen-2, and 30% expressed TATI. In patients with stage III and IV disease, TATI tissue expression (P = 0.002) and elevated TATI concentration in serum (P = 0.048) were associated with adverse cancer-specific and progression-free survival in univariate analysis. In multivariate analysis, TATI tissue expression (P = 0.005), tumor grade (P = 0.0001), histological type (P = 0.02), and stage (P = 0.0005) were independent prognostic factors for adverse cancer-specific survival and TATI tissue expression (P = 0.006) and grade (P = 0.0003) for progression-free survival. In multivariate analysis of all patients and those with advanced disease, serum trypsin-2-API concentration was an adverse prognostic factor for cancer-specific and progression-free survival, and it was independent of stage and histological type of the tumor (P <or= 0.01).

CONCLUSIONS

Tissue expression of TATI and an elevated preoperative serum concentration of trypsin-2-API are strong independent prognostic factors in advanced epithelial ovarian cancer. These results suggest that trypsin expression plays a role in the progression of ovarian cancer. TATI and trypsin-2-API are of potential use as an aid for stratification of randomized studies and for selecting treatment strategies.

The prognostic value of serum inhibin, 17 beta-estradiol and progesterone in cases of hydatidiform mole

The purpose of this study was to provide a diagnostic and a prognostic variable that could easily be measured in the laboratory, and that would predict the need for future therapy of persistent gestational trophoblastic disease. There would no longer be a need to treat all cases of hydatidiform mole prophylactically, to improve the outcome in only about 20% predicted to develop malignant gestational trophoblastic tumors. Circulating beta-human chorionic gonadotropin (beta-hCG), progesterone, 17 beta-estradiol and inhibin levels were measured using standard radioimmunoassays in 60 patients with complete hydatidiform mole and in 20 normal pregnant women of a corresponding duration of pregnancy and having a maternal indication for therapeutic abortion. There were no significant statistical differences between the two groups as regards gravidity, parity and gestational age. There was a significant statistical difference between patients with a molar pregnancy who developed gestational trophoblastic tumors (GTT) and those who did not develop GTT as regards pre-evacuation and follow-up mean serum beta-hCG, mean serum progesterone and mean serum 17 beta-estradiol levels. These findings together with the persistently elevated mean serum progesterone and mean serum 17 beta-estradiol levels at 6 weeks after evacuation in all cases who developed GTT suggested that progesterone as well as 17 beta-estradiol serum levels might be of prognostic value in cases of molar pregnancy. However, larger numbers of cases are required to correlate findings to beta-hCG serum level. Although mean serum inhibin level was significantly higher in women with hydatidiform mole than in normal pregnant women, it lacks any prognostic value for detection of subsequent gestational trophoblastic tumors.

GnRH analogues as an adjuvant therapy for ovarian cancer patients

OBJECTIVES

Lowering gonadotropin levels with gonadotropin-releasing hormone (GnRH) analogues in patients with ovarian cancer remains open to debate. The aim of this study was to assess the results of treatment in stage III and stage IV ovarian cancer patients who had surgery supplemented with chemotherapy, radiotherapy, and GnRH analogues. Gonadotropin levels were monitored during treatment.

METHODS

The study group comprised 69 patients aged 27-70 years, stratified according to the type of treatment. The overall disease-free, 5-year survival rates and the frequency of remissions were analyzed. Hormonal tests [follicle-stimulating hormone (FSH) and luteinizing hormone (LH)] were performed in 58 patients. Associations were checked between gonadotropin levels, clinical findings, and survival. The results were statistically compared.

RESULTS

Statistically significant differences were noted when chemotherapy was supplemented with GnRH analogues and/or radiotherapy. Administration of GnRH analogues resulted in significantly lower levels of LH than of FSH. Levels of FSH were significantly lower in patients surviving at least 5 years or in complete remission at the time of this study.

CONCLUSIONS

Combined therapy can produce favorable results in late-stage ovarian cancer, and GnRH analogues have an important role in treatment strategy.

Are serum inhibin concentrations new markers of placental tumours in the course of chemotherapy?

BACKGROUND

The study was conducted to evaluate whether the detection of serum molecular forms of inhibin (A and B) could be useful for the diagnosis, prognosis and follow-up of placental tumours.

METHODS

A total of 17 patients with hydatidiform mole (n = 13), invasive mole (n = 1) or choriocarcinoma (n = 3) were studied; serum concentrations of inhibins A and B, human chorionic gonadotrophin (HCG) and its free beta subunit (HCGbeta) were measured before chemotherapy (after mole evacuation for eight patients) and also during the course of chemotherapy (for 10 patients).

RESULTS

After evacuation or before chemotherapy for refractory disease, serum inhibin A and B concentrations were found to be increased in 10/17 and 4/17 patients, when HCG and HCGbeta were high in all patients. In 10 patients with a follow-up during treatment, nine had a high concentration of inhibin A which correlated with those of HCG and HCGbeta. Normalization of inhibin A was faster than that of HCG and HCGbeta for three and six patients respectively. There was no correlation between changes of inhibin B and HCGbeta concentrations.

CONCLUSIONS

Our results suggest that inhibins A and B are not useful markers and that HCG determination still remains the most useful marker for diagnosis and follow-up of placental tumours.

Preoperative serum concentration of hCGbeta as a prognostic factor in ovarian cancer

In spite of a gradual improvement, survival in epithelial ovarian cancer is disappointingly low. New therapeutic regimens are emerging, and it would be important to be able to predict the prognosis and to stratify patients for clinical trials before therapy. We have evaluated the prognostic value of the pretreatment serum concentrations of 3 tumor markers. The free beta subunit of human chorionic gonadotropin (hCGbeta), CA125 and tumor-associated trypsin inhibitor (TATI) were measured in pretreatment serum samples from 146 patients treated for ovarian cancer between 1990-1995. The patients were followed up until 1998. Elevated concentrations of hCGbeta, CA125 and TATI were observed in 29%, 79% and 33%, respectively. When tested as single variables in Cox's proportional hazards model, stage, grade, size of residual tumor and hCGbeta (all p < 0.001) and CA125 (p = 0.004) correlated with prognosis. However, when fitted as multiple variables together with stage, grade and age in the same model, hCGbeta (RR = 3.42) stage (RR = 2.77) and grade (RR = 3.80) were the only significant variables. When serum hCGbeta was normal, 5-year survival was 80%, but it was only 22% when hCGbeta was elevated. In patients with stage III or IV and minimal residual disease, 5-year survival was 75% if hCGbeta was normal compared with 0% if hCGbeta was elevated. hCGbeta in serum is a strong independent prognostic factor in epithelial ovarian cancer, and its prognostic value is similar to that of grade and stage. The availability of this marker before surgery could facilitate selection of treatment modalities.

Serum inhibin, activin and follistatin in postmenopausal women with epithelial ovarian carcinoma

OBJECTIVE

To investigate the role of serum inhibin A, inhibin pro-alphaC immunoreactivity, activin A, and follistatin in postmenopausal women with epithelial ovarian cancer.

DESIGN

Case-control study.

SAMPLE

e Serum samples from 27 postmenopausal women with epithelial ovarian cancer and 54 controls from the general population participating in an ovarian cancer screening trial.

RESULTS

Women with epithelial ovarian cancer had significantly higher serum levels of pro-alphaC immunoreactivity (P = 0.03), activin A (P = 0.004) and follistatin (P = 0.04), but not inhibin A (P = 0.13). Using the 90th centile in the control group as the cut off, pro-alphaC levels were elevated in 41% of women with epithelial ovarian cancer, while inhibin A was elevated in only 15%. Using the 95th centile as the cut off, serum pro-alphaC was elevated in only 11% of women with epithelial ovarian cancer (3/27), while activin A was elevated in 48% (11/23). Follicle stimulating hormone levels were significantly lower in women with epithelial ovarian cancer (P = 0.01). Although, inhibin-related peptides can modulate follicle stimulating hormone levels, there was no correlation between inhibin A, pro-alphaC immunoreactivity, activin A or follistatin and follicle stimulating hormone.

CONCLUSION

These data demonstrate that though there is preferential secretion of precursor forms of the alpha subunit rather than dimeric inhibin A by epithelial ovarian cancer, pro-alphaC is unlikely to be a useful tumour marker. Activin A is more commonly elevated in postmenopausal women with epithelial ovarian cancer and its role as a tumour marker in the diagnosis and screening of epithelial ovarian cancer warrants further evaluation.