Expression profiling in ovarian clear cell carcinoma: identification of hepatocyte nuclear factor-1 beta as a molecular marker and a possible molecular target for therapy of ovarian clear cell carcinoma

Transcriptional upregulation of HNF-1β by NF-κB in ovarian clear cell carcinoma modulates susceptibility to apoptosis through alteration in bcl-2 expression

Hepatocyte nuclear factor-1β (HNF-1β) is a transcriptional factor that has an important role in endometriosis-ovarian clear cell carcinoma (OCCC) sequence by modulating cell kinetics and glucose metabolism. However, little is known about the detailed molecular mechanisms that govern its regulation and function. Herein, we focus on upstream and downstream regulatory factors of HNF-1β in OCCCs. In clinical samples, HNF-1β expression was positively correlated with the active form of NF-κB/p65 in OCCCs, and closely linked with a low nuclear grade and non-solid architecture. In cell lines, transfection of p65 resulted in increased HNF-1β mRNA and protein expression in TOV-21G cells (OCCC cell line with endogenous HNF-1β expression), in line with activation of the promoter, probably through interacting with the basic transcriptional machinery. Suppression of endogenous HNF-1β expression by siRNA increased apoptosis in TOV-21G cells, while treatment of Hec251 cells (endometrial carcinoma cell line with extremely low endogenous HNF-1β expression) stably overexpressing exogenous HNF-1β with doxorubicin abrogated apoptosis of the cells, along with increased ratio of bcl-2 relative to bax. Moreover, overexpression of HNF-1β led to upregulation of bcl-2 expression at the transcriptional level in TOV-21G cells, which provided evidence for a positive correlation between HNF-1β and bcl-2 expression in OCCCs. These data, therefore, suggest that association between HNF-1β and NF-κB signaling may participate in cell survival by alteration of apoptotic events, particularly in mitochondria-mediated pathways, through upregulation of bcl-2 expression in OCCCs.

Combined use of COX-1 and VEGF immunohistochemistry refines the histopathologic prognosis of renal cell carcinoma

The course of RCC is asymptomatic, resulting in 25-30% of patients presenting with metastatic disease at time of diagnosis. The development of novel agents targeting angiogenesis and signal transduction pathways has improved patient outcomes. Role of cyclooxygenase in cancer development has been the subject of close scrutiny. COX-1 has been recognized to be involved in regulation of angiogenesis. To date, no immunohistochemical studies have been performed to assess the possible association between COX-1 and VEGF in RCC. This study is designed to evaluate the relationship between these two proteins in RCC. Also, the relationship between their combined immunohistochemical expression and different clinicopathological prognostic parameters in RCC is investigated. Immunohistochemical expression of COX-1 and VEGF was evaluated retrospectively on 64 cases of primary RCC including: 45 clear cell carcinoma, 12 papillary carcinoma and 7 of chromophope carcinoma. High COX-1 expression was detected in 62.5% of RCCs with a significant association with tumor grade (P=0.028), and highly significant relationship with tumor size and stage (P=0.001). There was a highly significant relationship between the VEGF score and tumor size (P=0.001), and stage (P=0.006). There was a positive correlation between COX-1 and VEGF expression score (P=0.001). Combined expression of both markers predicts high stage tumors (stage III/IV). Immunohistochemical expression of COX-1 and VEGF is associated with poor prognostic parameters in RCC. Their combined expression has a beneficial role in prediction of high stage tumors (III/IV).

Diagnostic value of dual detection of hepatocyte nuclear factor 1 beta (HNF-1β) and napsin A for diagnosing ovarian clear cell carcinoma

We evaluated the diagnostic value of hepatocyte nuclear factor 1 beta (HNF-1β) and napsin A for diagnosing ovarian clear cell carcinoma. Immunohistochemical EnVision was used to measure HNF-1β and napsin A expression in 38 cases of ovarian clear cell carcinoma, 30 cases of high-grade serous carcinoma, 22 cases of endometrioid adenocarcinoma, and 16 metastatic Krukenberg tumor cases. Then we found that HNF-1β appeared in all ovarian clear cell carcinoma and was less common in high-grade serous and endometrioid adenocarcinoma (P < 0.05). However, no significant difference in HNF-1β between clear cell carcinoma and metastatic Krukenberg tumor was found (P > 0.05). Napsin A was expressed in 97.4% of ovarian clear cell carcinoma, 6.7% high-grade serous carcinoma, 22.7% endometrioid adenocarcinoma, and 0% metastatic Krukenberg tumors. Napsin A in clear cell carcinoma was greater than that found in high-grade serous carcinoma, endometrioid adenocarcinoma, and metastatic Krukenberg tumor (P < 0.05). Sensitivity and specificity of HNF-1β and napsin A for diagnosing ovarian clear cell carcinoma was 100% and 54.4%, and 97.4% and 89.7%, respectively. Sensitivity and specificity of HNF-1β and napsin A for diagnosing ovarian clear cell carcinoma was 97.4% and 91.2%, respectively. So it is concluded that HNF-1β and napsin A are more sensitive than currently used markers for diagnosing ovarian clear cell carcinoma. Moreover, napsin A is more specific than HNF-1β. Combining HNF-1β and napsin A may distinguish clear cell carcinoma from high-grade serous carcinoma, endometrioid adenocarcinoma and metastatic Krukenberg tumors.

Novel biomarker candidates for the diagnosis of ovarian clear cell carcinoma

Ovarian clear cell carcinoma can arise from endometriosis; however, it is distinct from other types of epithelial ovarian carcinoma in terms of its clinicopathological and molecular features. Cancer antigen 125 lacks the sensitivity and specificity required for accurate clinical diagnosis of clear cell carcinoma. Therefore, the aim of the current review was to identify novel biomarker candidates for the immunohistochemical and serological diagnosis of clear cell carcinoma. A search of the relevant English language literature published between 1966 and 2014 was conducted using the PubMed MEDLINE online database. High-throughput tissue microarray technology and proteomic screening combined with mass spectrometry may provide additional information regarding diagnostic biomarker candidates for ovarian clear cell carcinoma. The present review summarizes the characteristics of potential genomic alterations that activate cancer signaling pathways and, thus, contribute to carcinogenesis. The major signaling pathways activated in clear cell carcinoma are associated with cell cycle regulation (hepatitis A virus cellular receptor 1 and tumor protein D52), growth factor signaling (insulin-like growth factor binding protein 1; KiSS-1 metastasis-suppressor; erb-b2 receptor tyrosine kinase 2; and fibroblast growth factor receptor 2), anti-apoptosis and survival pathways [sialidase 3 (membrane sialidase)], metabolism (γ-glutamyltransferase 1), chemoresistance (napsin A aspartic peptidase, glutathione peroxidase 3; and aldehyde dehydrogenase 1 family, member A1), coagulation [coagulation factor III (thromboplastin, tissue factor); and tissue factor pathway inhibitor 2], signaling (lectin, galactoside-binding and soluble, 3), and adhesion and the extracellular matrix [cadherin 1, type 1, E-cadherin (epithelial); versican; and laminin, α 5]. The present review of the relevant literature may provide a basis for additional clinical investigation of the ovarian clear cell carcinoma serum biomarker candidate proteins identified herein.

Integrated copy number and expression analysis identifies profiles of whole-arm chromosomal alterations and subgroups with favorable outcome in ovarian clear cell carcinomas

Ovarian clear cell carcinoma (CCC) is generally associated with chemoresistance and poor clinical outcome, even with early diagnosis; whereas high-grade serous carcinomas (SCs) and endometrioid carcinomas (ECs) are commonly chemosensitive at advanced stages. Although an integrated genomic analysis of SC has been performed, conclusive views on copy number and expression profiles for CCC are still limited. In this study, we performed single nucleotide polymorphism analysis with 57 epithelial ovarian cancers (31 CCCs, 14 SCs, and 12 ECs) and microarray expression analysis with 55 cancers (25 CCCs, 16 SCs, and 14 ECs). We then evaluated PIK3CA mutations and ARID1A expression in CCCs. SNP array analysis classified 13% of CCCs into a cluster with high frequency and focal range of copy number alterations (CNAs), significantly lower than for SCs (93%, P < 0.01) and ECs (50%, P = 0.017). The ratio of whole-arm to all CNAs was higher in CCCs (46.9%) than SCs (21.7%; P < 0.0001). SCs with loss of heterozygosity (LOH) of BRCA1 (85%) also had LOH of NF1 and TP53, and LOH of BRCA2 (62%) coexisted with LOH of RB1 and TP53. Microarray analysis classified CCCs into three clusters. One cluster (CCC-2, n = 10) showed more favorable prognosis than the CCC-1 and CCC-3 clusters (P = 0.041). Coexistent alterations of PIK3CA and ARID1A were more common in CCC-1 and CCC-3 (7/11, 64%) than in CCC-2 (0/10, 0%; P < 0.01). Being in cluster CCC-2 was an independent favorable prognostic factor in CCC. In conclusion, CCC was characterized by a high ratio of whole-arm CNAs; whereas CNAs in SC were mainly focal, but preferentially caused LOH of well-known tumor suppressor genes. As such, expression profiles might be useful for sub-classification of CCC, and might provide useful information on prognosis.

Checkpoint kinase 1 inhibitors as targeted molecular agents for clear cell carcinoma of the ovary

In clear cell carcinoma of the ovary, chemoresistance frequently results in treatment failure. The present study aimed to review the potential association of transcription factor hepatocyte nuclear factor (HNF)-1β with cell cycle checkpoint machinery, as a mechanism for chemoresistance. The English-language literature on the subject was reviewed to identify genomic alterations and aberrant molecular pathways interacting with chemoresistance in clear cell carcinoma. Oxidative stress induced by repeated hemorrhage induces greater susceptibility of endometriotic cells to DNA damage, and subsequent malignant transformation results in endometriosis-associated ovarian cancer. Molecular changes, including those in HNF-1β and checkpoint kinase 1 (Chk1), may be a manifestation of essential alterations in cell cycle regulation, detoxification and chemoresistance in clear cell carcinoma. Chk1 is a critical signal transducer in the cell cycle checkpoint machinery. DNA damage, in turn, increases persistent phosphorylation of Chk1 and induction of G2/M phase cell cycle arrest in cells overexpressing HNF-1β. HNF-1β deletion induces apoptosis, suggesting that enhanced levels of HNF-1β may be associated with chemoresistance. Targeted therapy with Chk1 inhibitors may be explored as a potential treatment modality for patients with clear cell carcinoma. This provides a novel direction for combination therapy, including targeting of Chk1, which may overcome drug resistance and improve treatment efficacy.

HNF1B polymorphism influences the prognosis of endometrial cancer patients: a cohort study

BACKGROUND

HNF1B (formerly known as TCF2) gene encodes for a transcription factor that regulates gene expression involved in normal mesodermal and endodermal developments. A close association between rs4430796 polymorphism of HNF1B gene and decreased endometrial cancer (EC) risk has been demonstrated. The aim of the current study was to test the hypothesis that rs4430796 polymorphism can influence the prognosis of EC patients.

METHODS

Retrospective cohort study. Clinical and pathological data were extrapolated and genotypes were assessed on formalin-fixed and paraffin-embedded non-tumour tissues. The influence of patients' genotype on overall survival and progression free survival were our main outcome measures.

RESULTS

A total of 191 EC patients were included in the final analysis. Overall survival differed significantly (P = 0.003) among genotypes. At multivariate analysis, a significant (P < 0.05) effect on overall survival was detected for FIGO stage, and rs4430796 polymorphism of HNF1B gene. After grouping EC patients according to adjuvant treatment, rs4430796 polymorphism resulted significantly (P < 0.001) related to overall survival only in subjects who received radiotherapy plus chemotherapy. A significant (P = 0.014) interaction between rs4430796 polymorphism and chemo-radiotherapy was also detected. Finally, only a trend (P = 0.090) towards significance was observed for rs4430796 polymorphism effect on progression free survival.

CONCLUSIONS

rs4430796 polymorphism of HNF1B gene influences independently the prognosis of EC patients with a potential effect on tumor chemo-sensitivity.

Expression of HNF-1β in cervical carcinomas: an immunohistochemical study of 155 cases

Background

HNF-1β is a commonly used marker in the differential diagnosis of clear cell carcinoma of the ovary and endometrium. Recent studies have found HNF-1β expression to a lesser extent in other ovarian and endometrial tumors including endometrioid, mucinous and, rarely, serous carcinoma. Regarding cervical carcinoma, HNF-1β expression has been mentioned exceptionally in mesonephric and some other types of adenocarcinoma. However, a systematic analysis of HNF-1β expression in cervical carcinomas has not been performed to date.

Methods

We analyzed HNF-1β expression in 155 cervical carcinomas (including 56 adenocarcinomas, 85 squamous cell carcinomas and 14 undifferentiated carcinomas). Expression of HNF-1β was correlated with the expression of other markers including estrogen receptors, progesterone receptors, CEA, p63, p40, p16, and D2-40.

Results

Adenocarcinomas showed expression of HNF-1β in 42/56 cases (75%), CEA in 48/56 cases (85.7%), p63 in 4/56 cases (7.2%), p40 in 2/56 cases (3.6%), estrogen receptors in 9/56 cases (16.1%), progesterone receptors in 5/56 cases (8.9%), p16 in 56/56 (100%) cases, and D2-40 in 0/56 cases (0%). Squamous cell carcinomas showed expression of HNF-1β in 2/85 cases (2.35%), CEA in 77/85 cases (90.6%), p63 and p40 in 85/85 cases (100%), estrogen receptors in 9/85 cases (10.6%), progesterone receptors in 1/85 cases (1.2%), p16 in 84/85 cases (98.8%), and D2-40 in 45/84 cases (53.6%). Undifferentiated carcinomas showed expression of HNF-1β in 2/14 cases (14.3%), CEA in 8/14 cases (57.1%), p16 in 14/14 cases (100%), hormone receptors in 0/13 cases (0%), p63 in 7/14 cases (50%), p40 in 5/14 cases (35.7%), and D2-40 in 1/14 cases (7.1%).

Conclusions

In cervical carcinoma, expression of HNF-1β is mostly restricted to adenocarcinomas and can be used as an auxiliary adenocarcinoma marker in the differential diagnosis of poorly differentiated cervical carcinomas. HNF-1β as an adenocarcinoma marker and p63/p40 and D2-40 as a squamous cell carcinoma markers are highly specific with variable sensitivity. Optimal results can be achieved using these markers in a panel.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1348836442160205.

Fine-mapping of the HNF1B multicancer locus identifies candidate variants that mediate endometrial cancer risk

Common variants in the hepatocyte nuclear factor 1 homeobox B (HNF1B) gene are associated with the risk of Type II diabetes and multiple cancers. Evidence to date indicates that cancer risk may be mediated via genetic or epigenetic effects on HNF1B gene expression. We previously found single-nucleotide polymorphisms (SNPs) at the HNF1B locus to be associated with endometrial cancer, and now report extensive fine-mapping and in silico and laboratory analyses of this locus. Analysis of 1184 genotyped and imputed SNPs in 6608 Caucasian cases and 37 925 controls, and 895 Asian cases and 1968 controls, revealed the best signal of association for SNP rs11263763 (P = 8.4 × 10(-14), odds ratio = 0.86, 95% confidence interval = 0.82-0.89), located within HNF1B intron 1. Haplotype analysis and conditional analyses provide no evidence of further independent endometrial cancer risk variants at this locus. SNP rs11263763 genotype was associated with HNF1B mRNA expression but not with HNF1B methylation in endometrial tumor samples from The Cancer Genome Atlas. Genetic analyses prioritized rs11263763 and four other SNPs in high-to-moderate linkage disequilibrium as the most likely causal SNPs. Three of these SNPs map to the extended HNF1B promoter based on chromatin marks extending from the minimal promoter region. Reporter assays demonstrated that this extended region reduces activity in combination with the minimal HNF1B promoter, and that the minor alleles of rs11263763 or rs8064454 are associated with decreased HNF1B promoter activity. Our findings provide evidence for a single signal associated with endometrial cancer risk at the HNF1B locus, and that risk is likely mediated via altered HNF1B gene expression.

Cystatin B as a potential diagnostic biomarker in ovarian clear cell carcinoma

Epithelial ovarian cancer (EOC) consists of four major subtypes: clear cell carcinoma (CCC), endometrioid adenocarcinoma (EA), mucinous adenocarcinoma (MA) and serous adenocarcinoma (SA). Relative to the other subtypes, the prognosis of CCC is poor due to a high recurrence rate and chemotherapy resistance, but CCC-specific biomarkers have yet to be identified. With the aim of identifying diagnostic and treatment biomarkers for CCC, we analyzed 96 cases of EOC (32 CCC, 13 EA, 19 MA, 32 SA) using liquid chromatography/mass spectrometry (LC/MS) followed by immunohistochemistry (IHC) and quantitative reverse transcription PCR (RT-qPCR). Semi-quantification of protein differences between subtypes showed upregulation of 150 proteins and downregulation of 30 proteins in CCC relative to the other subtypes. Based on hierarchical clustering that revealed a marked distinction in the expression levels of cystatin B (CYTB) and Annexin A4 (ANXA4) in CCC relative to the other subtypes, we focused the study on CYTB and ANXA4 expression in EOCs by IHC, RT-qPCR and western blot analyses using tissue specimens and cultured cells. As a result, compared to the other subtypes, CCC showed significantly high expression levels of CYTB and ANXA4 in the analyses. To examine the possibility of CYTB and ANXA4 as serum diagnostic biomarkers of CCC, we checked the protein levels in conditioned media and cell lysates using culture cells. Compared with the other subtypes, CCC cell lines showed a significantly higher level of expression of CYTB in both conditioned media and cell lysates, while ANXA4 showed a higher level of expression in cell lysates only. Our results demonstrate that CYTB and ANXA4 overexpression may be related to carcinogenesis and histopathological differentiation of CCC. CYTB may be a secreted protein, and may serve as a potential serum diagnostic biomarker of CCC, while ANXA4 may be useful as an intracellular marker.

The Utility of Immunohistochemistry in the Differential Diagnosis of Gynecologic Disorders

Context

Immunohistochemistry has assumed an increasing role in the identification and characterization of gynecologic disorders including lesions with deceptively bland morphology, uncommon and underdiagnosed neoplasms, and neoplasms with specific genetic alterations associated with overexpression or loss of expression of specific proteins. The diagnostic accuracy has been significantly improved owing to the discovery and increasing experience with the tumor-associated biomarkers, and the increasing demand for precise tumor classification to assess suitability for the expanding therapeutic modalities including clinical trials.

Objective

To differentiate lesions of the gynecologic tract through the use of effective immunohistochemical panels.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

The application of diagnostic and prognostic immunohistochemical panels has enabled pathologists to better guide therapeutic decisions and to better predict the clinical outcome. It is now well established that the use of ancillary testing, including immunohistochemistry, has a significant power in the identification, differentiation, and classification of reactive, premalignant, and malignant gynecologic disorders. This article discusses the utilities and pitfalls of the commonly used immunohistochemical markers in the context of overlapping morphologic features encountered in the uterus, ovaries, and fallopian tubes.

Napsin A is a specific marker for ovarian clear cell adenocarcinoma

Ovarian clear cell adenocarcinoma has a relatively poor prognosis among the ovarian cancer subtypes because of its high chemoresistance. Differential diagnosis of clear cell adenocarcinoma from other ovarian surface epithelial tumors is important for its treatment. Napsin A is a known diagnostic marker for lung adenocarcinoma, and expression of napsin A is reported in a certain portion of thyroid and renal carcinomas. However, napsin A expression in ovarian surface epithelial tumors has not previously been examined. In this study, immunohistochemical analysis revealed that in 71 of 86 ovarian clear cell adenocarcinoma patients (83%) and all of the 13 patients with ovarian clear cell adenofibroma, positive napsin A staining was evident. No expression was observed in 30 serous adenocarcinomas, 11 serous adenomas or borderline tumors, 19 endometrioid adenocarcinomas, 22 mucinous adenomas or borderline tumors, 10 mucinous adenocarcinomas, or 3 yolk sac tumors of the ovary. Furthermore, expression of napsin A was not observed in the normal surface epithelium of the ovary, epithelia of the fallopian tubes, squamous epithelium, endocervical epithelium, or the endometrium of the uterus. Therefore, we propose that napsin A is another sensitive and specific marker for distinguishing ovarian clear cell tumors (especially adenocarcinomas) from other ovarian tumors.

Metastatic ovarian carcinoma to the brain: an approach to identification and classification for neuropathologists

Brain metastasis is an uncommon but increasing manifestation of ovarian epithelial carcinoma and neuropathologists' collective experience with these tumors is limited. We present clinicopathological characteristics of 13 cases of brain metastases from ovarian epithelial carcinoma diagnosed at two academic institutions. The mean ages at diagnosis of the ovarian carcinoma and their subsequent brain metastases were 58.7 and 62.8 years, respectively. At the time of initial diagnosis of ovarian carcinoma the majority of patients had an advanced stage and none had brain metastases as their first manifestation of malignancy. Brain metastases tended to be multiple with ring-enhancing features on neuroimaging. Primary tumors and their brain metastases were all high-grade histologically and the histologic subtypes were: nine high-grade serous carcinoma (HGSC) cases, two clear cell carcinoma (CCC) cases and a single case each of carcinosarcoma and high-grade adenocarcinoma. A recommended histo- and immunopathological approach to these tumours are provided to aid neuropathologists in the recognition and classification of metastatic ovarian carcinoma to the brain.

MicroRNA-21 is a candidate driver gene for 17q23-25 amplification in ovarian clear cell carcinoma

BACKGROUND

Epithelial ovarian cancer (EOC) is the most common cause of gynecological malignancy-related mortality. Ovarian clear cell carcinoma (CCC) has unique clinical characteristics and behaviors that differ from other histological types of EOC, including a frequent association with endometriosis and a highly chemoresistant nature, resulting in poor prognosis. However, factors underlying its malignant behavior are still poorly understood. Aberrant expression of microRNAs has been shown to be involved in oncogenesis, and microRNA-21 (miR-21) is frequently overexpressed in many types of cancers. The aim of this study was to investigate the role of miR-21 in 17q23-25 amplification associated with CCC oncogenesis.

METHODS

We identified 17q23-25 copy number aberrations among 28 primary CCC tumors by using a comparative genomic hybridization method. Next, we measured expression levels of the candidate target genes, miR-21 and PPM1D, for 17q23-25 amplification by real-time RT-PCR analysis and compared those data with copy number status and clinicopathological features. In addition, immunohistochemical analysis of PTEN (a potential target of miR-21) was performed using the same primary CCC cases. We investigated the biological significance of miR-21 overexpression in CCC using a loss-of-function antisense approach.

RESULTS

17q23-25 amplification with both miR-21 overexpression and PTEN protein loss was detected in 4/28 CCC cases (14.2%). The patients with 17q23-25 amplification had significantly shorter progression-free and overall survival than those without 17q23-25 amplification (log-rank test: p = 0.0496; p = 0.0469, respectively). A significant correlation was observed between miR-21 overexpression and endometriosis. Both PTEN mRNA and PTEN protein expression were increased by miR-21 knockdown in CCC cells. We also confirmed that miR-21 directly bound to the 3'-untranslated region of PTEN mRNA using a dual-luciferase reporter assay.

CONCLUSIONS

MiR-21 is a possible driver gene other than PPM1D for 17q23-25 amplification in CCC. Aberrant expression of miR-21 by chromosomal amplification might play an important role in CCC carcinogenesis through the regulation of the PTEN tumor suppressor gene.

Gynecologic Cancer InterGroup (GCIG) consensus review for clear cell carcinoma of the ovary

Clear cell carcinoma of the ovary (CCC) is a histologic subtype of epithelial ovarian cancer with a distinct clinical behavior. There are marked geographic differences in the prevalence of CCC. The CCC is more likely to be detected at an early stage than high-grade serous cancers, and when confined within the ovary, the prognosis is good. However, advanced disease is associated with a very poor prognosis and resistance to standard treatment. Cytoreductive surgery should be performed for patients with stage II, III, or IV disease. An international phase III study to compare irinotecan/cisplatin and paclitaxel/carboplatin as adjuvant chemotherapy for stage IIV CCC has completed enrollment (GCIG/JGOG3017). Considering the frequent PIK3CA mutation in CCC, dual inhibitors targeting PI3K, AKT in the mTOR pathway, are promising. Performing these trials and generating the evidence will require considerable international collaboration.

Expression of bile duct transcription factor HNF1β predicts early tumor recurrence and is a stage-independent prognostic factor in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) frequently exhibits biliary differentiation, which is typically overlooked. Hepatocyte nuclear factor 1β (HNF1β), a bile duct-specific transcription factor expressed in bile ducts but not in the normal hepatocytes, is also expressed in HCC.

MATERIALS AND METHODS

The expression of HNF1β and the biliary differentiation marker cytokeratin 19 (CK19) were retrospectively evaluated using immunohistochemistry in 159 surgically resected primary HCCs.

RESULTS

A significant correlation was observed between HNF1β protein expression and younger age (p = 0.0293), high serum α-fetoprotein levels (p = 6 × 10(-4)), and high tumor grade (p = 0.0255). However, HNF1β expression exhibited no correlation with tumor stage. Patients with HCCs and HNF1β expression were more likely to exhibit early tumor recurrence (ETR; p = 0.0048) and a lower 5-year survival rate (p = 0.0001). A multivariate analysis indicated HNF1β expression as an independent prognostic factor in HCC (p = 0.0048). A combinatorial analysis revealed additive adverse effects of HNF1β when concomitant with CK19 expression and p53 mutation. Furthermore, HNF1β expression can predict poor prognosis in patients with ETR.

CONCLUSION

Our results indicated that HNF1β expression is a crucial predictor of poor prognosis in HCC and is independent of tumor stage. Moreover, concomitant HNF1β and CK19 expressions exhibited additive adverse effects in HCC, confirming that HCC with biliary differentiation has a poor prognosis.

Epigenetic and genetic dispositions of ovarian carcinomas

Ovarian clear cell carcinoma has unique clinical characteristics with slow growth and a stress-resistant phenotype that is epigenetically induced during cancer progression in an inflammatory microenvironment. We refer to this as an epigenetic disposition, which is frequently associated with unique biomolecular features including prominent alterations in methylation, microsatellite instability and ARID1A mutations. This characteristic methylation profile also affects glucose metabolism, commonly known as the Warburg effect. In contrast, high-grade ovarian serous adenocarcinoma has a genetic disposition that is accompanied by rapid growth, TP53 mutations and chromosomal instability. The concept of epigenetic and genetic dispositions is applicable to various malignancies, including gastric and colorectal cancers. These disposition classifications are based on fundamental characteristics of malignancies and may provide a new vantage point for development of individualized therapies.

Nicotinamide N-methyltransferase enhances the capacity of tumorigenesis associated with the promotion of cell cycle progression in human colorectal cancer cells

Nicotinamide N-methyltransferase (NNMT), an enzyme involved in the biotransformation and detoxification of many drugs and xenobiotic compounds, has been found to be overexpressed in several malignancies, including colorectal cancer. However, the biological function of NNMT and the related mechanisms in colorectal cancer have not been elucidated. In the present study, we investigated the effects of NNMT on tumorigenesis by overexpressing NNMT in the human colorectal cancer cells line SW480 which lacks constitutive NNMT expression, and downregulating NNMT expression in HT-29 cells, which exhibit high endogenous expression of NNMT. We found that NNMT significantly accelerates cell proliferation, enhances colony formation in vitro and tumorigenicity in mice; it also inhibits apoptosis, promotes cell cycle progression, increases ATP and 1-methylnicotinamide level and decreases ROS level. We also showed that 1-methylnicotinamide accelerates cell growth, inhibits apoptosis, promotes cell cycle progression, attenuates ROS production and increases ATP level. Our results indicate that NNMT enhances the capacity of tumorigenesis associated with the inhibition of cell apoptosis and the promotion of cell cycle progression in human colorectal cancer cells and the 1-methylnicotinamide increased by NNMT mediates the cellular effects of NNMT in cells. NNMT may play a vital role in energy balance and ROS induction.

Epigenetic determinants of ovarian clear cell carcinoma biology

Targeted approaches have revealed frequent epigenetic alterations in ovarian cancer, but the scope and relation of these changes to histologic subtype of disease is unclear. Genome-wide methylation and expression data for 14 clear cell carcinoma (CCC), 32 non-CCC and four corresponding normal cell lines were generated to determine how methylation profiles differ between cells of different histological derivations of ovarian cancer. Consensus clustering showed that CCC is epigenetically distinct. Inverse relationships between expression and methylation in CCC were identified, suggesting functional regulation by methylation, and included 22 hypomethylated (UM) genes and 276 hypermethylated (HM) genes. Categorical and pathway analyses indicated that the CCC-specific UM genes were involved in response to stress and many contain hepatocyte nuclear factor (HNF) 1-binding sites, while the CCC-specific HM genes included members of the estrogen receptor alpha (ERalpha) network and genes involved in tumor development. We independently validated the methylation status of 17 of these pathway-specific genes, and confirmed increased expression of HNF1 network genes and repression of ERalpha pathway genes in CCC cell lines and primary cancer tissues relative to non-CCC specimens. Treatment of three CCC cell lines with the demethylating agent Decitabine significantly induced expression for all five genes analyzed. Coordinate changes in pathway expression were confirmed using two primary ovarian cancer datasets (p < 0.0001 for both). Our results suggest that methylation regulates specific pathways and biological functions in CCC, with hypomethylation influencing the characteristic biology of the disease while hypermethylation contributes to the carcinogenic process.

Src as a novel therapeutic target for endometriosis

BACKGROUND

Endometriosis is a common condition that is associated with an increased risk of developing ovarian carcinoma. Improved in vitro models of this disease are needed to better understand how endometriosis, a benign disease, can undergo neoplastic transformation, and for the development of novel treatment strategies to prevent this progression.

METHODS

We describe the generation and in vitro characterization of novel TERT immortalized ovarian endometriosis epithelial cell lines (EEC16-TERT).

RESULTS

Expression of TERT alone was sufficient to immortalize endometriosis epithelial cells. TERT immortalization induces an epithelial-to-mesenchymal transition and perturbation in the expression of genes involved in the development of ovarian cancer. EEC16-TERT was non-tumorigenic when xenografted into immunocompromised mice but grew in anchorage-independent growth assays in an epidermal growth factor and hydrocortisone dependent manner. Colony formation in agar was abolished by inhibition of Src, and the Src pathway was found to be activated in human endometriosis lesions.

CONCLUSIONS

This new in vitro model system mimics endometriosis and the early stages of neoplastic transformation in the development of endometriosis associated ovarian cancer. We demonstrate the potential clinical relevance of this model by identifying Src activation as a novel pathway in endometriosis that could be targeted therapeutically, perhaps as a novel strategy to manage endometriosis clinically, or to prevent the development of endometriosis-associated ovarian cancer.

HNF-1β in ovarian carcinomas with serous and clear cell change

Many ovarian tumors, including high-grade serous carcinoma (HGSC), show clear cell change. Accurate diagnosis is important, however, as ovarian clear cell carcinoma (OCCC) is known to be less responsive to traditional types of ovarian cancer chemotherapies. In a previous study, the clinical, morphologic, and immunohistochemical features of 32 ovarian carcinomas, which had been previously diagnosed as pure OCCC (n=11), pure HGSC (n=11), and mixed serous and clear cell (MSC) (n=10), were analyzed. The immunoreactivities of WT1, ER, and p53, as well as the mitotic indices and stages of presentation of the MSC, were similar to those of HGSC. It was consequently concluded that MSC represented HGSC with clear cell change. Hepatocyte nuclear factor-1β (HNF-1β) is a relatively new immunohistochemical marker that has been shown to be rather sensitive and specific for OCCC. We thus sought to evaluate this marker in this specific group of tumors. One block each of pure HGSC and pure OCCC were stained with HNF-1β. In the cases of MSC, 2 blocks were stained when the serous and clear cell components were not present on the same slide. None (0/11) of the pure HGSC showed immunoreactivity for HNF-1β, whereas all (11/11) of the pure OCCC were positive. In the cases of MSC, both the serous and clear cell components were negative for HNF-1β. HNF-1β seems to be a sensitive and specific marker for OCCC and is not expressed in HGSC with clear cell change. The pattern of immunoreactivity of HNF-1β in tumors with both serous and clear cell change supports the conclusion that MSC are HGSC with clear cells.

Inhibition of Cell Death and Induction of G2 Arrest Accumulation in Human Ovarian Clear Cells by HNF-1β Transcription Factor: Chemosensitivity Is Regulated by Checkpoint Kinase CHK1

Objective

Appropriate cell cycle checkpoints are essential for the maintenance of normal cells and chemosensitivity of cancer cells. Clear cell adenocarcinoma (CCA) of the ovary is highly resistant to chemotherapy. Hepatocyte nuclear factor-1β (HNF-1β) is known to be overexpressed in CCA, but its role and clinical significance is unclear. We investigated the role of HNF-1β in regulation of the cell cycle in CCA.

Methods

To clarify the effects of HNF-1β on cell cycle checkpoints, we compared the cell cycle distribution and the expression of key proteins involved in CCA cells in which HNF-1β had been stably knocked down and in vector-control cell lines after treatment with bleomycin. HNF-1β (+) cells were arrested in G2 phase because of DNA damage.

Results

HNF-1β (−) cells died because of a checkpoint mechanism. G2 arrest of HNF-1β (+) cells resulted from sustained CHK1 activation, a protein that plays a major role in the checkpoint mechanism. HNF-1β (+) cells were treated with a CHK1 inhibitor after bleomycin treatment. Flow cytometric analysis of the cell cycle demonstrated that DNA damage–induced G2-arrested cells were released from the checkpoint and killed by a CHK1 inhibitor.

Conclusions

The chemoresistance of CCA may be due to aberrant retention of the G2 checkpoint through overexpression of HNF-1β. This is the first study demonstrating cell cycle regulation and chemosensitization by a CHK1 inhibitor in CCA.

Bioenergetic analysis of ovarian cancer cell lines: profiling of histological subtypes and identification of a mitochondria-defective cell line

Epithelial ovarian cancer (EOC) is the most lethal of all gynecological cancers, and encompasses distinct histological subtypes that have specific genetic and tissues-of-origin differences. Ovarian clear cell carcinoma (OCCC) represents approximately 10% of cases and has been termed a stress responsive cancer. OCCC is characterized by increased expression of oxidative stress and glycolysis-related genes. In the present study, we hypothesized that bioenergetic profiling might uniquely distinguish OCCC from other EOC histological subtypes. Using an extracellular flux analyzer, OCCC lines (ES-2, TOV-21-G) were shown to be highly metabolically active, with high oxygen consumption rate (OCR) and high extracellular acidification rate (ECAR), indicative of enhanced mitochondrial oxidative phosphorylation and glycolytic rate, respectively. A high bioenergetics profile was associated with the cell lines' ability to form anchorage independent spheroids. Given their high glycolytic and mitochondrial activity, OCCC cells displayed strong sensitivity to 2-deoxy-D-glucose and Rotenone growth inhibition, although this chemosensitivity profile was not specific to only OCCC cells. Bioenergetic profiling also identified a non-OCCC cell line, OVCA420, to have severely compromised mitochondrial function, based on low OCR and a lack of stimulation of maximal respiration following application of the uncoupler FCCP. This was accompanied by mitochondrial morphology changes indicative of enhanced fission, increased expression of the mitochondrial fission protein Drp1, a loss of mitochondrial membrane potential and dependence on glycolysis. Importantly, this loss of mitochondrial function was accompanied by the inability of OVCA420 cells to cope with hypoxic stress, and a compromised ability to stabilize HIF-1α in response to 1% O₂ hypoxia. This knowledge may be imperative for researchers planning to utilize this cell line for further studies of metabolism and hypoxia, and suggests that altered mitochondrial fission dynamics represents a phenotype of a subpopulation of EOCs.

Frequent somatic mutations of the telomerase reverse transcriptase promoter in ovarian clear cell carcinoma but not in other major types of gynaecological malignancy

Up-regulated expression of telomerase reverse transcriptase (TERT) and subsequent maintenance of telomere length are essential in tumour development. Recent studies have implicated somatic gain-of-function mutations at the TERT promoter as one of the mechanisms that promote transcriptional activation of TERT; however, it remains unclear whether this genetic abnormality is prevalent in gynaecological neoplasms. We performed mutational analysis in a total of 525 gynaecological cancers, and correlated TERT promoter mutations with clinicopathological features. With the exception of ovarian clear cell carcinomas, in which mutations were found in 37 (15.9%) of 233 cases, the majority of gynaecological malignancies were wild-type. TERT promoter mutation does not appear to be an early event during oncogenesis, as it was not detected in the contiguous endometriosis associated with ovarian clear cell carcinoma. Ovarian clear cell carcinoma cell lines with TERT promoter mutations exhibited higher TERT mRNA expression than those with wild-type sequences (p = 0.0238). TERT promoter mutation tended to be mutually exclusive with loss of ARID1A protein expression (p = 4.4 × 10(-9) ) and PIK3CA mutation (p = 0.0019) in ovarian clear cell carcinomas. No associations with disease-specific survival were observed for ovarian clear cell carcinoma. The above results, in conjunction with our previous report showing longer telomeres in ovarian clear cell carcinomas relative to other types of ovarian cancer, suggests that aberrations in telomere biology may play an important role in the pathogenesis of ovarian clear cell carcinoma.

Polyubiquitinated proteins, proteasome, and glycogen characterize the particle-rich cytoplasmic structure (PaCS) of neoplastic and fetal cells

A particle-rich cytoplasmic structure (PaCS) concentrating ubiquitin-proteasome system (UPS) components and barrel-like particles in clear, cytoskeleton- and organelle-free areas has recently been described in some neoplasms and in genetic or infectious diseases at risk of neoplasia. Ultrastructurally similar particulate cytoplasmic structures, interpreted as glycogen deposits, have previously been reported in clear-cell neoplasms and some fetal tissues. It remains to be investigated whether the two structures are the same, colocalize UPS components and polysaccharides, and have a role in highly proliferative cells such as fetal and neoplastic cells. We used immunogold electron microscopy and confocal immunofluorescence microscopy to examine human and mouse fetal tissues and human neoplasms. Fetal and neoplastic cells both showed colocalization of polyubiquitinated proteins, 19S and 20S proteasomes, and polysaccharides, both glycogen and chondroitin sulfate, inside cytoplasmic structures showing all distinctive features of PaCSs. Poorly demarcated and/or hybrid (ribosomes admixed) UPS- and glycogen-enriched areas, likely stages in PaCS development, were also seen in some fetal cells, with special reference to those, like primary alveolar pulmonary cells or pancreatic centroacinar cells, having a crucial role in organogenesis. UPS- and glycogen-rich PaCSs developed extensively in clear-cell neoplasms of the kidney, ovary, pancreas, and other organs, as well as, in infantile, development-related tumors replicating fetal patterns, such as choroid plexus papilloma. UPS-mediated, ATP-dependent proteolysis and its potential energy source, glycogen metabolism, may have a crucial, synergic role in embryo-/organogenesis and carcinogenesis.

Overexpression of cyclooxygenase-1 correlates with poor prognosis in renal cell carcinoma

The aim of this study was to evaluate expression of COX-1 in renal cell carcinoma (RCC) and its prognostic value. mRNA of COX-1 was detected in 42 paired RCC and adjacent normal tissues with quantitative real- time polymerase chain reaction (qRT-PCR). Expression of COX-1 was also evaluated in 196 RCC sections and 91 adjacent normal tissues with immunohistochemistry. Statistical analysis was performed to assess COX-1 expression in RCC and its prognostic significance. The results of qRT-PCR showed mRNA levels of COX-1 in RCC tissues to be significantly higher than that in adjacent normal tissues (p < 0.001). Immunohistochemical assays also revealed COX-1 to be overexpressed in RCC tissues (p < 0.001). Statistical analysis demonstrated high expression of COX-1 was correlated with tumour size (p = 0.002), pathological stage (p = 0.003), TNM stage (p = 0.003, 0.007, 0.027, respectively), and tumour recurrence (p < 0.001). Survival analysis indicated patients with high expression of COX-1 had shorter survival time (p < 0.001), and COX-1 was an independent predictor. This is the first study to reveal overexpression of COX-1 in RRC and point to use as a prognostic marker in affected patients.

Down-regulation of nicotinamide N-methyltransferase induces apoptosis in human breast cancer cells via the mitochondria-mediated pathway

Nicotinamide N-methyltransferase (NNMT) has been found involved in cell proliferation of several malignancies. However, the functional role of NNMT in breast cancer has not been elucidated. In the present study, we showed that NNMT was selectively expressed in some breast cancer cell lines, down-regulation of NNMT expression in Bcap-37 and MDA-MB-231 cell lines by NNMT shRNA significantly inhibited cell growth in vitro, decreased tumorigenicity in mice and induced apoptosis. The silencing reciprocal effect of NNMT was confirmed by over-expressing NNMT in the MCF-7 and SK-BR-3 breast cancer cell lines which lack constitutive expression of NNMT. In addition, down-regulation of NNMT expression resulted in reducing expression of Bcl-2 and Bcl-xL, up-regulation of Bax, Puma, cleaved caspase-9, cleaved caspase-3 and cleaved PARP, increasing reactive oxygen species production and release of cytochrome c from mitochondria, and decreasing the phosphorylation of Akt and ERK1/2. These data suggest that down-regulation of NNMT induces apoptosis via the mitochondria-mediated pathway in breast cancer cells.

Novel three-dimensional in vitro models of ovarian endometriosis

Background

Endometriosis is characterized by the presence of functional endometrial tissue outside of the uterine cavity. It affects 1 in 10 women of reproductive age. This chronic condition commonly leads to consequences such as pelvic pain, dysmenorrhea, infertility and an elevated risk of epithelial ovarian cancer. Despite the prevalence of endometriosis and its impact on women’s lives, there are relatively few in vitro and in vivo models available for studying the complex disease biology, pathophysiology, and for use in the preclinical development of novel therapies. The goal of this study was to develop a novel three-dimensional (3D) cell culture model of ovarian endometriosis and to test whether it is more reflective of endometriosis biology than traditional two dimensional (2D) monolayer cultures.

Methods

A novel ovarian endometriosis epithelial cell line (EEC16) was isolated from a 34-year old female with severe endometriosis. After characterization of cells using in vitro assays, western blotting and RNA-sequencing, this cell line and a second, already well characterized endometriosis cell line, EEC12Z, were established as in vitro 3D spheroid models. We compared biological features of 3D spheroids to 2D cultures and human endometriosis lesions using immunohistochemistry and real-time semi-quantitative PCR.

Results

In comparison to normal ovarian epithelial cells, EEC16 displayed features of neoplastic transformation in in vitro assays. When cultured in 3D, EEC16 and EEC12Z showed differential expression of endometriosis-associated genes compared to 2D monolayer cultures, and more closely mimicked the molecular and histological features of human endometriosis lesions.

Conclusions

To our knowledge, this represents the first report of an in vitro spheroid model of endometriosis. 3D endometriosis models represent valuable experimental tools for studying EEC biology and the development of novel therapeutic approaches.

Expression patterns of candidate susceptibility genes HNF1β and CtBP2 in prostate cancer: association with tumor progression

OBJECTIVES

Genome-wide association studies have identified variants at multiple loci associated with prostate cancer (PCa) risk. Some of these loci include candidate susceptibility genes, such as MSMB, HNF1β, and C-terminal-binding protein (CtBP2). Except for MSMB, the clinicopathological significance of these genes has not been investigated. We therefore aimed to analyze their expression in PCa tissues, in relation with tumor progression and aggressiveness.

METHODS AND MATERIALS

Protein expression was evaluated by immunohistochemistry on tissue microarrays containing samples from normal prostate (NL, n = 91), high-grade prostatic intraepithelial neoplasia (PIN, n = 61), clinically localized PCa (CLC, n = 434), PCa metastases (M, n = 28), and castration-resistant PCa (CRC, n = 49). Moreover, mRNA expression for each marker was assessed by quantitative real-time polymerase chain reaction, on 53 frozen samples of NL, CLC, and CRC.

RESULTS

These genes were differentially expressed at the different stages of PCa natural history. MSMB expression decreased with disease development and progression. In contrast, nuclear HNF1β and CtBP2 staining significantly increased in the CRC and M groups when compared with CLC, together with the transcripts levels. In patients with CLC, HNF1β and CtBP2 nuclear expressions were strongly associated with cancer cell proliferation. After adjusting for the Gleason score and the pathological stage, none of the candidate genes was significantly predictive of recurrence after radical prostatectomy. In patients with CRC, CtBP2 nuclear staining was associated with shorter overall survival.

CONCLUSIONS

The decrease of MSMB expression during tumor progression strongly supports its role as a tumor-suppressor gene. Although its functions remain to be clarified in PCa cells, HNF1β and CtBP2 are associated with cancer cell proliferation, tumor progression, and castration-resistant disease.

Annexin A4 is involved in proliferation, chemo-resistance and migration and invasion in ovarian clear cell adenocarcinoma cells

Ovarian clear cell adenocarcinoma (CCC) is the second most common subtype of ovarian cancer after high-grade serous adenocarcinomas. CCC tends to develop resistance to the standard platinum-based chemotherapy, and has a poor prognosis when diagnosed in advanced stages. The ANXA4 gene, along with its product, a Ca⁺⁺-binding annexin A4 (ANXA4) protein, has been identified as the CCC signature gene. We reported two subtypes of ANXA4 with different isoelectric points (IEPs) that are upregulated in CCC cell lines. Although several in vitro investigations have shown ANXA4 to be involved in cancer cell proliferation, chemoresistance, and migration, these studies were generally based on its overexpression in cells other than CCC. To elucidate the function of the ANXA4 in CCC cells, we established CCC cell lines whose ANXA4 expressions are stably knocked down. Two parental cells were used: OVTOKO contains almost exclusively an acidic subtype of ANXA4, and OVISE contains predominantly a basic subtype but also a detectable acidic subtype. ANXA4 knockdown (KO) resulted in significant growth retardation and greater sensitivity to carboplatin in OVTOKO cells. ANXA4-KO caused significant loss of migration and invasion capability in OVISE cells, but this effect was not seen in OVTOKO cells. We failed to find the cause of the different IEPs of ANXA4, but confirmed that the two subtypes are found in clinical CCC samples in ratios that vary by patient. Further investigation to clarify the mechanism that produces the subtypes is needed to clarify the function of ANXA4 in CCC, and might allow stratification and improved treatment strategies for patients with CCC.

Utility of α-methylacyl-coenzyme-A racemase (p504s) immunohistochemistry in distinguishing endometrial clear cell carcinomas from serous and endometrioid carcinomas

The expression of α-methylacyl-coenzyme-A racemase (AMACR) has previously been reported in 75% to 100% of urethral/bladder clear cell carcinomas, tumors that are known to display broad phenotypic overlap with their identically named müllerian counterparts. Herein, we assess the utility of AMACR in distinguishing endometrial clear cell carcinomas (CCCs) from endometrial serous carcinomas (ESCs) and endometrial endometrioid carcinomas (EECs). A total of 111 endometrial carcinomas in a tissue microarray, including 49 CCCs, 13 ESCs, and 49 EECs, were assessed for AMACR immunoreactivity, with results scored semiquantitatively (scores 0, 1+, 2+, 3+ for 0%, 1%-5%, 6%-50%, >50% immunoreactive cells, respectively). Fifty (45%) of the 111 carcinomas were AMACR positive, with the following score distribution: CCC: 0 (n = 12), 1+ (n = 12), 2+ (n = 3), 3+ (n = 22); EEC: 0 (n = 38), 1+ (n = 4), 2+ (n = 4), 3+ (n = 3); ESC: 0 (n = 11), 1+ (n = 1), 2+ (n = 0), 3+ (n = 1). AMACR expression was significantly more frequent in CCC (75%) than in ESC (15%) or EEC (22%); P < .0001. The sensitivity and specificity of AMACR expression in classifying a carcinoma as CCC were 0.75 (95% confidence interval [CI], 0.61-0.86) and 0.79 (95% CI, 0.66-0.88), respectively, with an odds ratio of 11.62 (95% CI, 5-28; P < .001) and an area under the curve of 0.79 (95% CI, 0.68-0.88). These findings indicate that AMACR expression is strongly associated with CCC and displays a relatively robust diagnostic test performance. However, its practical utility may be limited by the focal nature of its expression in 32% of the AMACR-positive CCC cases as well as its expression in 15% to 22% of the non-CCC histotypes.

Hepatocyte nuclear factor-1β is not a specific marker of clear cell carcinoma in serous effusions

BACKGROUND

The transcription factor hepatocyte nuclear factor-1β (HNF1β) has been reported to be a specific clear cell carcinoma marker, but its role in the diagnosis of serous effusions is largely unexplored. The objective of this study was to assess the diagnostic role of 2 commercial antibodies against HNF1β in effusion specimens.

METHODS

Effusions (n = 101), consisting of 43 ovarian adenocarcinomas (26 serous, 14 clear cell, 3 endometrioid), 37 nonovarian adenocarcinomas, 10 malignant mesotheliomas, 2 nonepithelial cancers, and 9 reactive specimens, were immunostained using antibodies from Santa Cruz Biotechnology Inc (Santa Cruz, Calif) and Atlas Antibodies AB (Stockholm, Sweden).

RESULTS

Use of the Santa Cruz antibody was associated with cytoplasmic or background staining in some specimens, whereas distinct staining with minimal background was observed using the Atlas antibody. The Santa Cruz antibody performed better in differentiating clear cell carcinoma from serous ovarian carcinoma and breast carcinoma, whereas staining was consistently negative in benign and malignant mesotheliomas using both antibodies. Distinct nuclear expression of HNF1β was observed in lung and gastrointestinal carcinomas, most often using the Atlas antibody.

CONCLUSIONS

The HNF1β antibody from Atlas performed better than its counterpart from Santa Cruz in terms of staining quality, but was less specific for clear cell carcinoma. Although HNF1β may be of diagnostic value in differentiating clear cell from serous carcinoma in cases with proven genital origin, the role of this marker is questionable in the differential diagnosis between the former tumors and adenocarcinomas of other origin, particularly in the setting of metastasis from an unknown primary tumor.

Hepatocyte nuclear factor-1β (HNF-1β) promotes glucose uptake and glycolytic activity in ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC) is a morphologically and biologically distinct subtype of ovarian carcinomas that often arises in ovarian endometriosis. We previously reported that a unique carcinogenic environment, especially iron-induced oxidative stress in endometriotic cysts may promote development of OCCC. We also identified a gene expression profile characteristic of OCCC (the "OCCC signature"). This 320-gene OCCC signature is enriched in genes associated with stress response and sugar metabolism. However, the biological implication of this profile is unclear. In this study, we have focused on the biological role of the HNF-1β gene within the OCCC signature, which was previously shown to be overexpressed in OCCC. Suppression of HNF-1β in the HNF-1β-overexpressing human ovarian cancer cell line RMG2 using short hairpin RNA resulted in a significant increase in proliferation. It also facilitated glucose uptake, glycolytic activity, and lactate secretion along with increased expression of the glucose transporter-1 (GLUT-1) gene and several key enzymes in the glycolytic process. Conversely, forced expression of HNF-1β in the serous ovarian cancer cell line, Hey, resulted in slowed cellular growth and repressed glycolytic activity. These data suggest that HNF-1β represses cell growth, and at the same time, it promotes aerobic glycolysis which is known as the "Warburg effect." As the Warburg effect is regarded as a characteristic metabolic process in cancer which may contribute to cell survival under hypoxic conditions or in a stressful environment, overexpression of HNF-1β may play an inevitable role in the occurrence of OCCC in stressful environment.

Integrative bioinformatics links HNF1B with clear cell carcinoma and tumor-associated thrombosis

Clear cell carcinoma (CCC) is a histologically distinct carcinoma subtype that arises in several organ systems and is marked by cytoplasmic clearing, attributed to abundant intracellular glycogen. Previously, transcription factor hepatocyte nuclear factor 1-beta (HNF1B) was identified as a biomarker of ovarian CCC. Here, we set out to explore more broadly the relation between HNF1B and carcinomas with clear cell histology. HNF1B expression, evaluated by immunohistochemistry, was significantly associated with clear cell histology across diverse gynecologic and renal carcinomas (P<0.001), as was hypomethylation of the HNF1B promoter (P<0.001). From microarray analysis, an empirically-derived HNF1B signature was significantly enriched for computationally-predicted targets (with HNF1 binding sites) (P<0.03), as well as genes associated with glycogen metabolism, including glucose-6-phophatase, and strikingly the blood clotting cascade, including fibrinogen, prothrombin and factor XIII. Enrichment of the clotting cascade was also evident in microarray data from ovarian CCC versus other histotypes (P<0.01), and HNF1B-associated prothrombin expression was verified by immunohistochemistry (P = 0.015). Finally, among gynecologic carcinomas with cytoplasmic clearing, HNF1B immunostaining was linked to a 3.0-fold increased risk of clinically-significant venous thrombosis (P = 0.043), and with a 2.3-fold increased risk (P = 0.011) in a combined gynecologic and renal carcinoma cohort. Our results define HNF1B as a broad marker of clear cell phenotype, and support a mechanistic link to glycogen accumulation and thrombosis, possibly reflecting (for gynecologic CCC) derivation from secretory endometrium. Our findings also implicate a novel mechanism of tumor-associated thrombosis (a major cause of cancer mortality), based on the direct production of clotting factors by cancer cells.

Toward an understanding of the pathophysiology of clear cell carcinoma of the ovary (Review)

Endometriosis-associated ovarian cancers demonstrate substantial morphological and genetic diversity. The transcription factor, hepatocyte nuclear factor (HNF)-1β, may be one of several key genes involved in the identity of ovarian clear cell carcinoma (CCC). The present study reviews a considerably expanded set of HNF-1β-associated genes and proteins that determine the pathophysiology of CCC. The current literature was reviewed by searching MEDLINE/PubMed. Functional interpretations of gene expression profiling in CCC are provided. Several important CCC-related genes overlap with those known to be regulated by the upregulation of HNF-1β expression, along with a lack of estrogen receptor (ER) expression. Furthermore, the genetic expression pattern in CCC resembles that of the Arias-Stella reaction, decidualization and placentation. HNF-1β regulates a subset of progesterone target genes. HNF-1β may also act as a modulator of female reproduction, playing a role in endometrial regeneration, differentiation, decidualization, glycogen synthesis, detoxification, cell cycle regulation, implantation, uterine receptivity and a successful pregnancy. In conclusion, the present study focused on reviewing the aberrant expression of CCC-specific genes and provided an update on the pathological implications and molecular functions of well-characterized CCC-specific genes.

Cellular, histologic, and molecular changes associated with endometriosis and ovarian cancer

Our understanding of the pathogenesis of endometriosis is rapidly evolving as early molecular events are increasingly identified. Endometriosis is associated with increased risk of ovarian cancer and exhibits neoplastic phenotypes including invasion of stromal tissue and lymphatic spread to distant organs. This review of the literature establishes the clinical, epidemiologic, and pathologic correlation between endometriosis and low-grade ovarian cancer. Genetic studies have demonstrated that endometriotic lesions have mutations in genes directly related to neoplasms, in particular the p53, KRAS, PTEN, and ARID1A genes, which suggests a direct transition from a subset of endometriotic lesions to invasive carcinomas. The identification of both genetic and epigenetic biomarkers including microRNAs are essential for identifying patients at risk for the transition to neoplasia.

GWAS meta-analysis and replication identifies three new susceptibility loci for ovarian cancer

Genome-wide association studies (GWAS) have identified four susceptibility loci for epithelial ovarian cancer (EOC), with another two suggestive loci reaching near genome-wide significance. We pooled data from a GWAS conducted in North America with another GWAS from the UK. We selected the top 24,551 SNPs for inclusion on the iCOGS custom genotyping array. We performed follow-up genotyping in 18,174 individuals with EOC (cases) and 26,134 controls from 43 studies from the Ovarian Cancer Association Consortium. We validated the two loci at 3q25 and 17q21 that were previously found to have associations close to genome-wide significance and identified three loci newly associated with risk: two loci associated with all EOC subtypes at 8q21 (rs11782652, P = 5.5 × 10(-9)) and 10p12 (rs1243180, P = 1.8 × 10(-8)) and another locus specific to the serous subtype at 17q12 (rs757210, P = 8.1 × 10(-10)). An integrated molecular analysis of genes and regulatory regions at these loci provided evidence for functional mechanisms underlying susceptibility and implicated CHMP4C in the pathogenesis of ovarian cancer.

Endometriosis-associated ovarian cancer: a review of pathogenesis

Endometriosis is classically defined as the presence of endometrial glands and stroma outside of the endometrial lining and uterine musculature. With an estimated frequency of 5%–10% among women of reproductive age, endometriosis is a common gynecologic disorder. While in itself a benign lesion, endometriosis shares several characteristics with invasive cancer, has been shown to undergo malignant transformation, and has been associated with an increased risk of epithelial ovarian carcinoma (EOC). Numerous epidemiologic studies have shown an increased risk of EOC among women with endometriosis. This is particularly true for women with endometrioid and clear cell ovarian carcinoma. However, the carcinogenic pathways by which endometriosis associated ovarian carcinoma (EAOC) develops remain poorly understood. Current molecular studies have sought to link endometriosis with EAOC through pathways related to oxidative stress, inflammation and hyperestrogenism. In addition, numerous studies have sought to identify an intermediary lesion between endometriosis and EAOC that may allow for the identification of endometriosis at greatest risk for malignant transformation or for the prevention of malignant transformation of this common gynecologic disorder. The objective of the current article is to review the current data regarding the molecular events associated with EAOC development from endometriosis, with a primary focus on malignancies of the endometrioid and clear cell histologic sub-types.

Identification of PCAG1 as a novel prostate cancer-associated gene

The aim of the present study was to identify a new prostate cancer‑associated gene and analyze its expression pattern. Comprehensive expression analysis of expressed sequence tags (ESTs) and microarray data and serial analysis of gene expression (SAGE) were conducted to screen in silico for candidate prostate cancer‑associated genes. Reverse transcription (RT)-PCR was performed to validate prostate cancer specificity. Prostate cancer‑associated gene 1 (PCAG1) was identified. The expression of PCAG1 mRNA and protein was evaluated in common human normal tissues, common malignant tumors, prostate adenocarcinoma and paired adjacent normal prostate tissues. An immunofluorescence assay was conducted to determine the subcellular location of PCAG1. PCAG1 mRNA was absent in the 15 pooled normal tissues (including normal prostate tissue) but registered at low levels in the spleen tissue (+). By contrast, PCAG1 mRNA was significantly higher than in the adjacent normal tissues in each of the 14 cases of prostate cancer, with ~50% scoring a high degree of expression (+++). Of the 32 types of normal tissues, 29 (including normal prostate tissue) demonstrated negative PCAG1 protein staining while the remaining tissues of the adrenal gland, parathyroid gland and liver expressed low levels. While 18/20 cases of prostate adenocarcinoma showed positive expression results, PCAG1 protein expression in the remaining types of cancer was scarce when present at all; only 41/380 other cancer cases demonstrated positive results at a low level. The most substantial PCAG1-positive expression results were identified by cytoplasmic staining in 36/38 prostate adenocarcinoma cases, with 10 cases showing high expression levels, 20 showing medium levels and 6 showing low levels. In the paired adjacent normal prostate tissues, only 3/38 cases showed low level positive staining, while 35/38 cases were negative. Immunofluorescent staining of the human prostate cancer PC3 cell line showed positive PCAG1 expression results in the mitochondria. The present study demonstrated that while PCAG1 mRNA was highly expressed in prostate cancer tissues, it was almost absent in all common normal tissues and paired adjacent normal prostate tissues. Furthermore, PCAG1 protein was also highly expressed in prostate cancer tissues, while few common normal tissues, other common malignant tumors and paired adjacent normal prostate tissues had even low levels of expression. Clarification of the function and transcriptional mechanism of PCAG1 may aid the elucidation of the mechanisms of carcinogenesis and progression of prostate cancer. The unique expression pattern of PCAG1 suggests its potential in certain clinical applications.

Epigenetic analysis leads to identification of HNF1B as a subtype-specific susceptibility gene for ovarian cancer

HNF1B is overexpressed in clear cell epithelial ovarian cancer, and we observed epigenetic silencing in serous epithelial ovarian cancer, leading us to hypothesize that variation in this gene differentially associates with epithelial ovarian cancer risk according to histological subtype. Here we comprehensively map variation in HNF1B with respect to epithelial ovarian cancer risk and analyse DNA methylation and expression profiles across histological subtypes. Different single-nucleotide polymorphisms associate with invasive serous (rs7405776 odds ratio (OR)=1.13, P=3.1 × 10(-10)) and clear cell (rs11651755 OR=0.77, P=1.6 × 10(-8)) epithelial ovarian cancer. Risk alleles for the serous subtype associate with higher HNF1B-promoter methylation in these tumours. Unmethylated, expressed HNF1B, primarily present in clear cell tumours, coincides with a CpG island methylator phenotype affecting numerous other promoters throughout the genome. Different variants in HNF1B associate with risk of serous and clear cell epithelial ovarian cancer; DNA methylation and expression patterns are also notably distinct between these subtypes. These findings underscore distinct mechanisms driving different epithelial ovarian cancer histological subtypes.