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

Tumor expression of human chorionic gonadotropin beta mRNA and prognosis of prostate cancer treated by radical prostatectomy

The beta subunit of human chorionic gonadotropin (hCGβ) is encoded by six genes (CGB) classified as type I and type II. CGB mRNA is produced in large amounts by trophoblastic tissues and in small amounts by several cancerous tissues including prostate cancer and by a few benign tissues, including the prostate. Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) was used to study the expression levels of all CGB mRNAs together (total CGB mRNA) and the two types of CGB mRNA separately in non-cancerous (n = 74) and cancerous prostatic tissue obtained by radical prostatectomy (n = 193). RNA was isolated from formalin-fixed paraffin-embedded (FFPE) samples and mRNA levels of CGB were correlated with disease-specific survival. Total CGB mRNA concentrations were significantly lower (p < .0001) in cancerous than non-cancerous prostatic tissue. Separate analysis of type I CGB and type II CGB mRNA showed that both type I CGB (p < .0001) and type II CGB mRNA (p = .007) are lower in cancerous tissue than in non-cancerous tissue. Low type II CGB mRNA level in cancerous tissue was associated with shorter cancer-specific survival (p = .001) of prostate cancer patients treated by radical prostatectomy.

Biomarker development, from bench to bedside

This review describes studies performed by our group and other laboratories in the field aimed at development of biomarkers not only for cancer but also for other diseases. The markers covered include tumor-associated trypsin inhibitor (TATI), tumor-associated trypsin (TAT), human chorionic gonadotropin (hCG), prostate-specific antigen (PSA) and their various molecular forms, their biology and diagnostic use. The discovery of TATI was the result of a hypothesis-driven project aimed at finding new biomarkers for ovarian cancer among urinary peptides. TATI has since proved to be a useful prognostic marker for several cancers. Recently, it has been named Serine Peptidase Inhibitor Kazal Type 1 (SPINK1) after being rediscovered by several groups as a tumor-associated peptide by gene expression profiling and proteomic techniques and shown to promote tumor development by stimulating the EGF receptor. To explain why a trypsin inhibitor is strongly expressed in some cancers, research focused on the protease that it inhibited led to the finding of tumor-associated trypsin (TAT). Elevated serum concentrations of TAT-2 were found in some cancer types, but fairly high background levels of pancreatic trypsinogen-2 limited the use of TAT-2 for cancer diagnostics. However, trypsinogen-2 and its complex with α1-protease inhibitor proved to be very sensitive and specific markers for pancreatitis. Studies on hCG were initiated by the need to develop more rapid and sensitive pregnancy tests. These studies showed that serum from men and non-pregnant women contains measurable concentrations of hCG derived from the pituitary. Subsequent development of assays for the subunits of hCG showed that the β subunit of hCG (hCGβ) is expressed at low concentrations by most cancers and that it is a strong prognostic marker. These studies led to the formation of a working group for standardization of hCG determinations and the development of new reference reagents for several molecular forms of hCG. The preparation of intact hCG has been adopted as the fifth international standard by WHO. Availability of several well-defined forms of hCG made it possible to characterize the epitopes of nearly 100 monoclonal antibodies. This will facilitate design of immunoassays with pre-defined specificity. Finally, the discovery of different forms of immunoreactive PSA in serum from a prostate cancer patient led to identification of the complex between PSA and α1-antichymotrypsin, and the use of assays for free and total PSA in serum for improved diagnosis of prostate cancer. Epitope mapping of PSA antibodies and establishment of PSA standards has facilitated establishment well-standardized assays for the various forms of PSA.

Expression of human chorionic gonadotropin in testicular germ cell tumors

BACKGROUND

We have shown that most patients with seminomas have elevated serum concentrations of the free β subunit of human chorionic gonadotropin (hCGβ) and that in nonseminomatous testicular cancer, most of the hCG in the serum is hyperglycosylated (hCG-h). However, the tissue expression of hCG-h or hCGβ in germ cell tumors (GCTs) has not been reported. Our objective was to study the expression and diagnostic value of hCG-h and hCGβ in testicular GCTs.

METHODS

We studied the immunohistochemical expression of hCG, hCG-h, hCGβ, and the free α subunit of hCG (hCGα) in GCTs from 154 patients. We compared the tissue expression with serum concentrations and evaluated the correlation between staining intensity, established prognostic variables, and outcome.

RESULTS

The expression varied between tumor types. All forms of hCG, including hCG-h, were detected in embryonal carcinomas (22%) and mixed GCTs (48%). Polyclonal hCG and monoclonal hCGβ antibodies detected immunoreactivity in some seminomas (7%). No form of hCG was found in spermatocytic seminomas, pure teratomas, or a yolk sac tumor. The serum concentrations correlated with the corresponding tumor expression. The staining intensities of hCG, hCGβ, hCG-h, and hCGα correlated with disease stage but not significantly with relapse, disease-related mortality, or progression-free survival.

CONCLUSION

Trophoblastic tissue expresses hCG, hCG-h, and free subunits together whereas seminoma tissue occasionally expresses hCGβ. This difference might aid in differential diagnosis of some difficult-to-classify cases.

Human chorionic gonadotropin beta subunit genes CGB1 and CGB2 are transcriptionally active in ovarian cancer

Human chorionic gonadotropin beta subunit (CGB) is a marker of pregnancy as well as trophoblastic and nontrophoblastic tumors. CGB is encoded by a cluster of six genes, of which type II genes (CGB3/9, 5 and 8) have been shown to be upregulated in relation to type I genes (CGB6/7) in both placentas and tumors. Recent studies revealed that CGB1 and CGB2, originally considered as pseudogenes, might also be active, however, the protein products of these genes have not yet been identified. Our study demonstrates the presence of CGB1 and CGB2 transcripts in ovarian carcinomas. While CGB1 and CGB2 gene activation was not detected in normal ovaries lacking cancerous development, our study demonstrates the presence of CGB1 and CGB2 transcripts in 41% of analyzed ovarian cancer cases.

Reduction of human chorionic gonadotropin beta subunit expression by modified U1 snRNA caused apoptosis in cervical cancer cells

Background

Secretion of human chorionic gonadotropin, especially its beta subunit by malignant trophoblastic tumors and varieties of tumors of different origin is now well documented; however the role of hCG in tumorogenesis is still unknown.

Results

This study documents the molecular presence of human chorionic gonadotropin beta subunit in uterine cervix cancer tissues and investigates a novel technique to reduce hCGβ levels based on expression of a modified U1 snRNA as a method to study the hormone's role in biology of human cervical cancer cells cultured in vitro. The property of U1 snRNA to block the accumulation of specific RNA transcript when it binds to its donor sequence within the 3' terminal exon was used. The first 10 nucleotides of the human U1 snRNA gene, which normally binds to the 5'ss in pre-mRNA were replaced by a sequence complementary to a 10-nt segment in the terminal exon of the hCGβ mRNA. Three different 5' end-mutated U1 snRNA expression plasmids were tested, each targeting a different sequence in the hCGβ mRNA, and we found each one blocked the expression of hCGβ in HeLa cells, a cervix carcinoma cell line, as shown by immunohistochemistry and qRT-PCR. Reduction of hCGβ levels resulted in a significantly increased apoptosis rate with almost 90% of cells transfected with modified anti-hCGβ U1 snRNAs showing morphological changes characteristic of the apoptotic process.

Conclusion

These data suggest that human chorionic gonadotropin beta subunit may act as a tumor growth-stimulating factor.

Expression of human chorionic gonadotropin beta-subunit type I genes predicts adverse outcome in renal cell carcinoma

Expression of the free beta-subunit of human chorionic gonadotropin (hCGbeta) in malignant tumors is frequently associated with aggressive disease. The pretreatment serum concentration of hCGbeta is an independent prognostic variable in renal cell carcinoma (RCC). The three so-called type II genes (hCGbeta 3/9, 5, and 8) have been shown to be up-regulated in relation to type I genes (hCGbeta 6/7) in some malignant tumors. We developed a reverse transcription-polymerase chain reaction method for quantification of relative levels of the mRNAs for the two types of hCGbeta genes and studied the association between the expression in RCC tissue (n = 104) and clinical outcome. hCGbeta mRNA expression was detected in 40% (42 of 104) of the tumors, and in 40 of these (93%), this consisted of hCGbeta type I mRNA only, whereas type II hCGbeta mRNA was detected in two samples. hCGbeta mRNA expression was significantly associated with a shorter disease-specific (log-rank P = 0.023; median survival 1.4 versus 7.9 years) and overall survival (log-rank P = 0.011). In a Cox regression model, stage (P < 0.0001) and hCGbeta mRNA expression (P < 0.0001) were independent prognostic variables. We conclude that expression of type I hCGbeta genes indicates adverse prognosis in RCC.

Overexpression of Human Chorionic Gonadotropin β Genes 3, 5 and 8 in Tumor Tissue and Urinary Cells of Bladder Cancer Patients

OBJECTIVE

Human chorionic gonadotropin (hCG) is a marker of trophoblastic tumors, and the serum concentration of the free beta-subunit (hCGbeta) is an independent prognostic marker in several nontrophoblastic cancers. hCGbeta is encoded by six genes, of which the type II genes (hCGbeta 3/9, 5 and 8) are thought to be upregulated in relation to type I genes (hCGbeta 6/7) in cancer.

METHOD

We developed a novel quantitative RT-PCR method for the quantification of the relative expression levels of the two groups of hCGbeta genes and analyzed 28 bladder tumors and 15 urine samples.

RESULTS

We found a higher relative expression level of type II genes in malignant compared with benign urothelia (p = 0.016) and in exfoliated urinary cells from cancer patients compared with those from benign controls (p = 0.026). The expression level was increasing with higher stage (p = 0.014) and grade (p = 0.001) and tended to be higher in relapsing tumors (p = 0.059).

CONCLUSION

The increased hCGbeta concentrations in body fluids of patients with aggressive bladder cancer may be due to overexpression of type II genes. Quantification of the relative mRNA expression levels of the hCGbeta type I and II genes in urine cells should be further studied as a potential noninvasive tool for the diagnosis and follow-up of bladder cancer.

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.

Favorable prognostic value of tissue human kallikrein 11 (hK11) in patients with ovarian carcinoma

Human kallikrein 11 (hK11/trypsin-like serine protease/TLSP, encoded by the KLK11 gene) is a member of the kallikrein family of secreted serine proteases. Recently, we developed a highly sensitive and specific immunoassay for hK11 and found that this protease is expressed in the prostate, stomach and trachea as well as in amniotic fluid and milk of lactating women. Elevated serum hK11 levels were found in 60% of men with prostate cancer and 70% of women with ovarian cancer. Also, hK11 expression was found to be under the regulation of steroid hormones, particularly estrogens, at the level of KLK11 transcription. We hypothesized that hK11 may be implicated in endocrine-related malignancies and serve as a novel prostate and ovarian cancer serological marker. The aim of our study was to examine if hK11 expression in ovarian tumors bears any prognostic significance. The concentration of hK11 (ng per mg of total protein) in 104 ovarian tumor cytosolic extracts was quantified and correlated with clinicopathologic variables and outcome over a median follow-up period of 67 months. Outcome was defined as progression-free survival (PFS) and overall survival (OS). hK11 concentration in ovarian tumor cytosols ranged from 0-21 ng/mg of total protein, with a median of 0.54 ng/mg. An optimal cutoff value of 0.54 ng/mg was selected to categorize tumors as hK11-positive or -negative. hK11-positive tumors were more frequently associated with early stage (Stage I/II) disease, pre-/peri-menopausal status and patients who exhibited complete or partial response to chemotherapy (p < 0.05). Univariate analysis revealed that patients with hK11-positive tumors had a significantly decreased risk of relapse with a hazard ratio (HR) of 0.45 (p = 0.007) and death (HR of 0.34, p = 0.005). Cox multivariate analysis indicated that hK11 was an independent prognostic indicator of OS (HR of 0.41, p = 0.025). Kaplan-Meier survival curves further confirmed that women with hK11-positive tumors have longer PFS and OS (p = 0.005 and p = 0.003, respectively). Similarly, in the subgroup of patients with grade 1-2 tumors, hK11-positivity was associated with higher OS in both univariate and multivariate analysis (HR of 0.23 and 0.17, p < 0.05). Finally, in women with optimal debulking after surgery (<1 cm residual tumor), hK11 positivity was associated with a slower disease progression. These results indicate that hK11 is a novel, independent marker of favorable prognosis in patients with ovarian cancer.