Clear cell carcinoma has an expression pattern of cell cycle regulatory molecules that is unique among ovarian adenocarcinomas

From clinical management to personalized medicine: novel therapeutic approaches for ovarian clear cell cancer

Ovarian clear-cell cancer is a rare subtype of epithelial ovarian cancer with unique clinical and biological features. Despite optimal cytoreductive surgery and platinum-based chemotherapy being the standard of care, most patients experience drug resistance and a poor prognosis. Therefore, novel therapeutic approaches have been developed, including immune checkpoint blockade, angiogenesis-targeted therapy, ARID1A synthetic lethal interactions, targeting hepatocyte nuclear factor 1β, and ferroptosis. Refining predictive biomarkers can lead to more personalized medicine, identifying patients who would benefit from chemotherapy, targeted therapy, or immunotherapy. Collaboration between academic research groups is crucial for developing prognostic outcomes and conducting clinical trials to advance treatment for ovarian clear-cell cancer. Immediate progress is essential, and research efforts should prioritize the development of more effective therapeutic strategies to benefit all patients.

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.

Distinct expression pattern and post-transcriptional regulation of cell cycle genes in the glandular epithelia of avian ovarian carcinomas

The cell cycle system is controlled in a timely manner by three groups of cyclins, cyclin dependent kinases and cyclin dependent kinase inhibitors. Abnormal alterations of cell cycle regulatory mechanisms are a common feature of many diseases including numerous tumor types such as ovarian cancer. Although a variety of cell cycle regulatory genes are well known in mammalian species including human and mice, they are not well studied in avian species, especially in laying hens which are recognized as an excellent animal model for research relevant to human ovarian carcinogenesis. Therefore, in the present study, we focused on comparative expression and regulation of expression of candidate genes which might be involved in the cell cycle program in surface epithelial ovarian cancer in laying hens. Our current results indicate that expression levels of cell cycle gene transcripts are greater in cancerous as compared to normal ovaries. In particular, cyclin A2 (CCNA2), CCND1, CCND2, CCND3, CCNE2, cyclin dependent kinase 1 (CDK1), CDK3, CDK5, cyclin dependent kinases inhibitor 1A (CDKN1A) and CDKN1B were upregulated predominantly in the glandular epithelia of cancerous ovaries from laying hens. Further, several microRNAs (miRs), specifically miR-1798, miR-1699, miR-223 and miR-1744 were discovered to influence expression of CCND1, CCNE2, CDK1, and CDK3 mRNAs, respectively, via their 3′-UTR which suggests that post-transcriptional regulation of gene expression influences their expression in laying hens. Moreover, miR-1626 influenced CDKN1A expression and miR-222, miR-1787 and miR-1812 regulated CDKN1B expression via their 3′-UTR regions. Collectively, results of the present study demonstrate increased expression of cell cycle-related genes in cancerous ovaries of laying hens and indicate that expression of these genes is post-transcriptionally regulated by specific microRNAs.

Promoter methylation status of HIN-1 associated with outcomes of ovarian clear cell adenocarcinoma

Background

This study is to analyze promoter methylation of various tumor suppressor genes in different types of ovarian carcinoma and to identify potential therapeutic targets of ovarian clear cell adenocarcinoma (OCCA).

Materials and methods

The promoter methylation statuses of 40 genes in primary ovarian carcinomas including 47 clear- and 63 non-clear-cell type tissues, 6 OCCA cell lines, 29 benign ovarian endometriotic cysts, and 31 normal controls were analyzed by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA). The MS-MLPA results were correlated with clinicopathological features and outcomes of 47 OCCA patients. Functions of the target genes were further explored by Western Blot Analysis, apoptosis assay, and caspase-3/7 activity analysis.

Results

Frequencies of methylated RASSF1A, CDH13, CACNA1A, HIN-1, and sFRP5 genes in OCCA tissues were significantly higher than those in non-OCCA cancerous tissues and benign endometriotic cysts. The expected OS for patients with methylated promoters of HIN-1 was significantly worse than those for patients without methylated HIN-1 (30% vs. 62%, p = 0.002). The HIN-1 gene was over-expressed in ES2 cells, a significant reduction in cell growth and induction of apoptosis, and increasing paclitaxel sensitivity by reducing phosphorylation of Akt were observed.

Conclusions

Methylation of HIN-1 promoter is a novel epigenetic biomarker associated with poor outcomes in OCCA patients. Ectopic expression of the HIN-1 gene increased paclitaxel sensitivity which is partly through Akt pathway.

Prognostic biomarkers in ovarian cancer

Epithelial ovarian cancer (EOC) remains the most lethal gynecological malignancy despite several decades of progress in diagnosis and treatment. Taking advantage of the robust development of discovery and utility of prognostic biomarkers, clinicians and researchers are developing personalized and targeted treatment strategies. This review encompasses recently discovered biomarkers of ovarian cancer, the utility of published prognostic biomarkers for EOC (especially biomarkers related to angiogenesis and key signaling pathways), and their integration into clinical practice.

Alterations in expression of specific microRNAs by combination of 4-HPR and EGCG inhibited growth of human malignant neuroblastoma cells

Malignant neuroblastomas are childhood tumors that remain mostly incurable. We explored efficacy of N-(4-hydroxyphenyl) retinamide (4-HPR) and (-)-epigallocatechin-3-gallate (EGCG) in altering expression of oncogenic microRNAs (OGmiRs) and tumor suppressor miRs (TSmiRs) for controlling growth of human malignant neuroblastoma SK-N-BE2 and IMR-32 cells. Combination of 4-HPR and EGCG most significantly decreased expression of OGmiRs (miR-92, miR-93, and miR-106b) and increased expression of TSmiRs (miR-7-1, miR-34a, and miR-99a) in both cell lines. Overexpression of miR-93 and miR-7-1, respectively, decreased and increased efficacy of treatments. Thus, alterations in expression of specific OGmiRs and TSmiRs by 4-HPR and EGCG inhibited growth of malignant neuroblastomas.

Prognostic impact of p53, p27, and C-MYC on clinicopathological features and outcome in early-stage (FIGO I-II) epithelial ovarian cancer

INTRODUCTION

The objective of the study was to evaluate the prognostic effect of p53, p27, and C-MYC on clinicopathological features, recurrent disease, and disease-free survival (DFS) of 131 patients with ovarian cancer in International Federation of Gynecology and Obstetrics (FIGO) stages I-II.

METHODS

The technique of tissue microarray and immunohistochemistry was used for detection of positivity/overexpression of the biological markers p53, p27, and C-MYC.

RESULTS

In the complete series, the 5-year and overall survival rates were 68% and 71%, respectively. Positive staining for p53, p27, and C-MYC was detected in 25%, 57%, and 76% of cases, respectively. Positivity of p53, p27, concomitant p53-p27, C-MYC, and C-MYC-p27 status were associated with tumor grade. Positivity of p27 and concomitant p53-p27 were related to serous tumors. In survival analysis, DFS was related to p53, combined p53-p27, and combined p53-C-MYC status. Significant predictive factors for tumor recurrences were the FIGO stage (odds ratio [OR] = 9.8), status of node sampling (OR = 0.2), and p53 status (OR = 3.7) in a logistic regression analysis. In a multivariate Cox regression analysis, FIGO stage (hazard ratio [HR] = 4.3) and p53 status (HR = 3.0) were significant prognostic factors for DFS. In a separate Cox regression analysis, FIGO stage (HR = 2.0) and concomitant p53-p27-C-MYC status (HR = 0.3) were independent prognostic factors for DFS. It was possible to identify a subgroup, constituting 30% of the patients, who had excellent survival with tumors of concomitant p53 negativity, p27 positivity, and C-MYC positivity apart from the clinicopathological factors. Patients in this subgroup were longtime survivors with DFS of 92% at 5 and 9 years.

CONCLUSIONS

The results of this study strongly suggest that patients with p53-positive tumors (alone/or combined with p27 and/or C-MYC) had significantly worse survival (DFS) compared with patients with p53-negative tumors. Patients with p53-positive tumors continued to have recurrences after the 5-year follow-up and die in disease.

Nonserous Ovarian Epithelial Tumors

This review covers the group of relatively uncommon nonserous ovarian epithelial tumors. The authors focus on the group's distinctiveness from the much more common serous tumors and show the similarities across entities. Diagnostic criteria that separate the different entities are currently being debated. Particular problems include the reproducible diagnosis of high-grade endometrioid, transitional cell, mixed epithelial and undifferentiated carcinomas. Furthermore, despite recognition that most malignant mucinous tumors involving ovary represent metastases from extraovarian primary sites, many misdiagnoses still occur. The authors discuss their rationale behind their opinions about these problematic topics.

Targeting annexin A4 to counteract chemoresistance in clear cell carcinoma of the ovary

IMPORTANCE OF THE FIELD

Epithelial ovarian cancer (EOC) is the leading cause of death from gynecological malignancies in Western countries. Among the four major histological subtypes of EOC, clear cell carcinoma (CCC) of the ovary is highly resistant to platinum-based chemotherapy and is consequently associated with poor patient prognosis in advanced stages.

AREAS COVERED IN THIS REVIEW

An overview of the clinical characteristics of ovarian CCC; the role of annexin family proteins in tumor development and progression; the role of annexin A4 in enhancing cellular drug resistance; recent studies linking annexin A4 overexpression to chemoresistance in tumors of ovarian CCC.

WHAT THE READER WILL GAIN

Insight into the emerging role for annexin A4 in enhancing chemoresistance in ovarian CCC.

TAKE HOME MESSAGE

Annexin A4 enhances cancer cell chemoresistance and is overexpressed in tumors of patients with ovarian CCC. Targeting of annexin A4 may represent a future strategy to counteract resistance to chemotherapy in ovarian CCC.

POLD2 and KSP37 (FGFBP2) correlate strongly with histology, stage and outcome in ovarian carcinomas

BACKGROUND

Epithelial ovarian cancer (EOC) constitutes more than 90% of ovarian cancers and is associated with high mortality. EOC comprises a heterogeneous group of tumours, and the causes and molecular pathology are essentially unknown. Improved insight into the molecular characteristics of the different subgroups of EOC is urgently needed, and should eventually lead to earlier diagnosis as well as more individualized and effective treatments. Previously, we reported a limited number of mRNAs strongly upregulated in human osteosarcomas and other malignancies, and six were selected to be tested for a possible association with three subgroups of ovarian carcinomas and clinical parameters.

METHODOLOGY/PRINCIPAL FINDINGS

The six selected mRNAs were quantified by RT-qPCR in biopsies from eleven poorly differentiated serous carcinomas (PDSC, stage III-IV), twelve moderately differentiated serous carcinomas (MDSC, stage III-IV) and eight clear cell carcinomas (CCC, stage I-IV) of the ovary. Superficial scrapings from six normal ovaries (SNO), as well as biopsies from three normal ovaries (BNO) and three benign ovarian cysts (BBOC) were analyzed for comparison. The gene expression level was related to the histological and clinical parameters of human ovarian carcinoma samples. One of the mRNAs, DNA polymerase delta 2 small subunit (POLD2), was increased in average 2.5- to almost 20-fold in MDSC and PDSC, respectively, paralleling the degree of dedifferentiation and concordant with a poor prognosis. Except for POLD2, the serous carcinomas showed a similar transcription profile, being clearly different from CCC. Another mRNA, Killer-specific secretory protein of 37 kDa (KSP37) showed six- to eight-fold higher levels in CCC stage I compared with the more advanced staged carcinomas, and correlated positively with an improved clinical outcome.

CONCLUSIONS/SIGNIFICANCE

We have identified two biomarkers which are markedly upregulated in two subgroups of ovarian carcinomas and are also associated with stage and outcome. The results suggest that POLD2 and KSP37 might be potential prognostic biomarkers.

Immunohistochemical evidence for the over-expression of Glutathione peroxidase 3 in clear cell type ovarian adenocarcinoma

Glutathione peroxidase 3 (GPX3) is a member of glutathione peroxidase family, exerting one of the most important cellular defense mechanisms against stress signals, including oxidative damage. In this study, the expression of GPX3 mRNA and protein was analyzed for ovarian cancer tissues to test its applicability as a biomarker that can distinguish the four major histologic types of epithelial ovarian cancer. A public microarray dataset containing 99 ovarian cancer and 4 normal ovary samples was downloaded, and GPX3 mRNA expression was analyzed. The expression of GPX3 protein was measured by immunohistochemical staining in 40 epithelial ovarian cancer tissues, 10 for each of the serous, endometrioid, mucinous, and clear cell type. Histoscores were made from the immunohistostaining, and analysis of variance (ANOVA) was performed to quantitate the differences in protein level. Analysis of genomic dataset confirms a GPX3 overexpression in clear cell type ovarian adenocarcinoma compared with normal ovary and 3 other subtypes of epithelial ovarian cancer at mRNA level. GPX3 also shows the highest average antibody staining intensities in clear cell type ovarian adenocarcinomas over the other 3 types in immunostaining on tissue arrays. This is the first validation of GPX3 as a clear cell type-specific biomarker in ovarian cancer patients' tissues by immunostaining. GPX3 may serve as an important molecular marker for the diagnosis and molecular understanding of clear cell carcinoma of the ovary.

p21 Promotes oncolytic adenoviral activity in ovarian cancer and is a potential biomarker

The oncolytic adenovirus dl922-947 replicates selectively within and lyses cells with a dysregulated Rb pathway, a finding seen in > 90% human cancers. dl922-947 is more potent than wild type adenovirus and the E1B-deletion mutant dl1520 (Onyx-015). We wished to determine which host cell factors influence cytotoxicity. SV40 large T-transformed MRC5-VA cells are 3-logs more sensitive to dl922-947 than isogenic parental MRC5 cells, confirming that an abnormal G1/S checkpoint increases viral efficacy. The sensitivity of ovarian cancer cells to dl922-947 varied widely: IC₅₀ values ranged from 51 (SKOV3ip1) to 0.03 pfu/cell (TOV21G). Cells sensitive to dl922-947 had higher S phase populations and supported earlier E1A expression. Cytotoxicity correlated poorly with both infectivity and replication, but well with expression of p21 by microarray and western blot analyses. Matched p21+/+ and -/- Hct116 cells confirmed that p21 influences dl922-947 activity in vitro and in vivo. siRNA-mediated p21 knockdown in sensitive TOV21G cells decreases E1A expression and viral cytotoxicity, whilst expression of p21 in resistant A2780CP cells increases virus activity in vitro and in intraperitoneal xenografts. These results highlight that host cell factors beyond simple infectivity can influence the efficacy of oncolytic adenoviruses. p21 expression may be an important biomarker of response in clinical trials.

Promoter methylation of sFRP5 in patients with ovarian clear cell adenocarcinoma

BACKGROUND

Specific tumour suppressor genes with promoter methylation in ovarian clear cell adenocarcinoma (OCCA) can be one important epigenetic mark distinguishing OCCA from ovarian serous adenocarcinoma (OSA), benign endometriotic cysts and normal ovarian epitheliums.

MATERIALS AND METHODS

Five OCCA cell lines, 63 cancer tissues (48 OCCA and 15 OSA), 10 benign endometriotic cysts and five normal ovarian epitheliums were analysed by methylation-specific PCR using pooled DNAs to determine the methylation status of the promoter of the target genes, including genes for secreted frizzled-related proteins (sFRP1 to 5), adenomatous polyposis coli (APC), retinoblastoma protein 1 (Rb1), breast cancer 1 gene (BRCA1), p14(ARF), p15(INK4b), p16(INK4a) and survivin. Methylation frequencies of identified targets were further analysed with individual DNA samples.

RESULTS

The sFRP5 promoter was significantly methylated in all OCCA cell lines, with 64.6% in OCCA tissues compared with 13.3% in OSA, and 0% in benign endometriotic cysts and normal ovarian epitheliums (P < 0.0001). With a median follow-up of 44 months, the expected 5-year overall survival (OS) for patients with methylated sFRP5 promoter were significantly worse than for those with unmethylated sFRP5 (52% vs. 88%, P = 0.03). After adjusting for age, stage, and residual disease after primary surgery, patients with unmethylated sFRP5 promoter had an independent good prognostic factor in OS (P = 0.017).

CONCLUSION

The high percentage of promoter methylation in the sFRP5 gene in OCCA indicates its importance in the development of OCCA and is a potential useful marker for prognoses and target for treatment of OCCA.

Cytoplasmic p27 expression is an independent prognostic factor in ovarian cancer

Dysregulation of the cell cycle is an important prerequisite for cancer development. p27 has an established role in cell cycle control and hence may be disrupted during carcinogenesis. The influence of p27 expression, including its subcellular location, on tumor behavior in ovarian cancer has been controversial. The purpose of this study was to evaluate the expression of p27 in a large population of patients with ovarian cancer and correlate this to clinicopathologic variables including overall survival. Using a tissue microarray of 339 primary ovarian cancers, the expression of p27 was assessed immunohistochemically. Coupled to a comprehensive database of clinicopathologic variables, its effect on these factors and survival was studied. Cytoplasmic p27 showed a progressively negative impact on overall survival (P=0.004). Tumors displaying nuclear p27 also had poorer prognosis (P=0.014). Factors shown to predict prognosis independently of each other were age, stage, and the absence of macroscopic disease after surgery. Cytoplasmic p27 expression, but not nuclear, was independently predictive of prognosis on multivariate analysis (P=0.042). Both subcellular locations of p27 expression were more frequently observed in serous compared with mucinous subtypes. Cytoplasmic p27 independently predicts poorer prognosis in ovarian carcinoma. These results seem counterintuitive, when considering the antiproliferative role of p27, but may reflect a more complex function of p27 within cell cycle regulation. These data support a novel role for p27 within the cytoplasm, possibly through effects on apoptosis, cellular motility, and drug resistance.

Identification of an ovarian clear cell carcinoma gene signature that reflects inherent disease biology and the carcinogenic processes

Ovarian clear cell carcinoma (OCCC) shows unique clinical features including an association with endometriosis and poor prognosis. We previously reported that the contents of endometriotic cysts, especially high concentrations of free iron, are a possible cause of OCCC carcinogenesis through iron-induced persistent oxidative stress. In this study, we conducted gene expression microarray analysis using 38 ovarian cancer cell lines and identified genes commonly expressed in both OCCC cell lines and clinical samples, which comprise an OCCC gene signature. The OCCC signature reproducibly predicts OCCC specimens in other microarray data sets, suggesting that this gene profile reflects the inherent biological characteristics of OCCC. The OCCC signature contains known markers of OCCC, such as hepatocyte nuclear factor-1beta (HNF-1beta) and versican (VCAN), and other genes that reflect oxidative stress. Expression of OCCC signature genes was induced by treatment of immortalized ovarian surface epithelial cells with the contents of endometriotic cysts, indicating that the OCCC signature is largely dependent on the tumor microenvironment. Induction of OCCC signature genes is at least in part epigenetically regulated, as we found hypomethylation of HNF-1beta and VCAN in OCCC cell lines. This genome-wide study indicates that the tumor microenvironment induces specific gene expression profiles that contribute to the development of distinct cancer subtypes.

A limited panel of immunomarkers can reliably distinguish between clear cell and high-grade serous carcinoma of the ovary

The distinction of ovarian clear cell carcinomas (CCCs) from high-grade serous carcinomas (HG-SCs) is sometimes a diagnostic challenge. With the recognition that CCCs respond poorly to conventional chemotherapy there are efforts to initiate clinical trials for CCC, making accurate diagnosis critical. The purpose of this study was to test and validate a set of antibodies that could aid in the diagnosis of CCC, using a series of cases from different centers in North America. Using a test set of 133 CCCs, we identified the following markers: Cyclin E, estrogen receptor, hepatocyte nuclear factor (HNF)-1beta, Ki-67, p21, p53, and Wilms tumor (WT)1 that show significant discrimination from 200 HG-SCs. For validation, these markers were characterized on an independent set of 104 CCCs from 3 other centers. There were no significant differences in expression of these 7 markers between the independent test and validation sets of CCC. Combining all CCC cases (N=237), HNF-1beta showed the highest sensitivity (82.5%) and specificity (95.2%) for CCC, and WT1 for HG-SC (sensitivity: 79.9%, specificity: 97.4%). A diagnostic panel consisting of WT1, ER, and HNF-1beta demonstrated nearly identical performance as a panel using all 7 markers in distinguishing CCCs from HG-SCs, correctly classifying 84% of cases. Three percent of cases were misclassified and 13% carried an uninformative triple negative immunophenotype. CCCs show a distinct, reproducible immunophenotype, compared with HG-SCs, and a panel of 3 immunomarkers can serve as a diagnostic aid in problematic cases.

PTEN promoter methylation and LOH of 10q22-23 locus in PTEN expression of ovarian clear cell adenocarcinomas

OBJECTIVES

Loss of phosphatase and tensin homolog (PTEN) expression is common in ovarian clear cell adenocarcinomas (OCCA), but PTEN mutations are not frequently observed in OCCA. The mechanism of PTEN gene silencing in OCCA is still not clear.

MATERIALS AND METHODS

Immunohistochemical analysis of PTEN expression was performed in 40 OCCA paraffin-embedded tissues. PTEN promoter methylation in 24 OCCA tissues and 5 OCCA cell lines was examined by methylation-specific PCR. Eighteen OCCA patients and 13 serous adenocarcinomas were analyzed for loss of heterozygosity (LOH) at 10q23 with five polymorphic markers.

RESULTS

Of the 40 OCCAs, 37.5% (15/40) had reduced PTEN immunoreactivity, LOH was found in 33% (6/18) of OCCAs, and 31% (4/13) of serous adenocarcinomas. In the 33% of OCCAs with LOH, only 33% (2/6) lost PTEN expression. PTEN promoter was unmethylated in 5 OCCA cell lines and 24 OCCA tissues detected by MSP-PCR. No significant correlation between PTEN expression and advanced stage disease or overall survival was found.

CONCLUSION

Our results indicate that reduced PTEN expression was detected in more than one third of OCCA cases. Neither PTEN promoter methylation nor LOH at 10q23 locus is significantly related to PTEN inactivation and is not an adverse prognostic factor in OCCA.

Serum and tissue biomarkers as predictive and prognostic variables in epithelial ovarian cancer

Tumour stage, residual disease after initial surgery, histological type and tumour grade are the most important clinical-pathological factors related to the clinical outcome of patients with epithelial ovarian cancer. In the last years, several investigations have assessed different biological variables in sera and in tissue samples from patients with this malignancy in order to detect biomarkers able to reflect either the response to chemotherapy or survival. The present paper reviewed the literature data about the predictive or prognostic relevance of serum CA 125, soluble cytokeratin fragments, serum human kallikreins, serum cytokines, serum vascular endothelial growth factor and plasma d-dimer as well as of tissue expression of cell cycle- and apoptosis-regulatory proteins, human telomerase reverse transcriptase, membrane tyrosine kinase receptors and matrix metalloproteinases. A next future microarray technology will hopefully offer interesting perspectives of translational research for the identification of novel predictive and prognostic biomarkers for epithelial ovarian cancer.

Clear cell adenocarcinoma arising from a giant cystic adenomyosis: a case report with immunohistochemical analysis of laminin-5 gamma2 chain and p53 overexpression

We report a case of a clear cell adenocarcinoma arising from a giant cystic adenomyosis, with immunohistochemical analysis of p53 and laminin-5 gamma2 chain overexpression. Microscopically, not only clear cell adenocarcinoma showing myometrial invasion but also single-layered clear cell adenocarcinoma cells lining the cyst wall were observed. Transition from these single-layered tumor cells to papillary proliferative lesions of various degrees was recognized. Moreover, these tumor cells were continuous with minimal atypical cells. Although the tumor cells within the uterus showed a low positive cell ratio for p53, the metastatic foci showed a remarkable p53 overexpression. Laminin-5 gamma2 chain expression was low in papillary proliferation and high in myometrial invasion and metastatic foci. The single-layered tumor cells showing non-invasive proliferation also contained laminin-5 gamma2 chain-positive cells. When non-invasive tumor cells were considered to be at an early stage in tumor progression, some tumor cells had already acquired an invasive feature. p53 overexpression was not related to expression of the laminin-5 gamma2 chain.

Emi1 protein accumulation implicates misregulation of the anaphase promoting complex/cyclosome pathway in ovarian clear cell carcinoma

Clear cell carcinoma is a clinically and pathologically distinct entity among surface epithelial ovarian neoplasms, recognized for its resistance to standard platinum-based chemotherapy at advanced stage disease and poor prognosis. Despite advances in our understanding of the biology of other surface epithelial ovarian neoplasms, very little is known about the molecular genetic mechanisms that are involved in clear cell tumorigenesis. Early mitotic inhibitor-1 (Emi1) protein is a key cell cycle regulator, that promotes S-phase and mitotic entry by inhibiting the anaphase promoting complex. In cell culture systems, overexpression of Emi1 leads to tetraploidy and genomic instability, especially in the absence of normal p53 function. We investigated Emi1 protein expression in ovarian neoplasms using a tissue microarray constructed from 339 primary ovarian surface epithelial (serous, endometrioid, clear cell, and mucinous) and peritoneal (serous) neoplasms, stromal and mesenchymal tumors, germ cell tumors, and normal ovarian tissue. Significant overexpression of Emi1 protein was present in 82% (27/33) clear cell carcinoma, including one borderline tumor in a diffuse, granular cytoplasmic and perinuclear staining pattern, independent of patient age, presence of ovarian and/or pelvic endometriosis, and FIGO stage. In contrast, only 10% (17/177) primary ovarian and primary peritoneal serous carcinomas, 0% (0/10) mucinous carcinomas, and 19% (6/32) endometrioid carcinomas exhibited significant Emi1 protein overexpression. Accumulation of Emi1 protein was not linked to Ki-67 labeling index, but was directly correlated with cyclin E and inversely correlated with ER in clear cell carcinoma (P<0.001). Emi1 protein expression was present in mixed endometrioid/clear cell tumors but absent in tumors with mixed serous/clear cell histology. These findings represent a potentially important insight into the molecular pathway underlying ovarian carcinogenesis and provide a possible cell cycle model for the development and progression of ovarian clear cell carcinoma.

Alteration of cell-cycle regulation in epithelial ovarian cancer

In spite of the clinical importance of epithelial ovarian cancer (EOC), little is known about the pathobiology of its precursor lesions and progression. Regulatory mechanisms of the cell cycle are mainly composed of cyclins, cyclin-dependent kinases (CDK), and CDK inhibitors. Alteration of these mechanisms results in uncontrolled cell proliferation, which is a distinctive feature of human cancers. This review describes the current state of knowledge about the alterations of cell-cycle regulations in the context of p16-cyclin D1-CDK4/6-pRb pathway, p21-p27-cyclin E-CDK2 pathway, p14-MDM2-p53 pathway, and ATM-Chk2-CDC25 pathway, respectively. Recent evidence suggests that ovarian cancer is a heterogenous group of neoplasms with several different histologic types, each with its own underlying molecular genetic mechanism. Therefore, expression of cell cycle regulatory proteins should be tested separately according to each histologic type. In serous ovarian carcinoma, high expression of p16, p53, and p27 and low expression of p21 and cyclin E were shown. In addition, this review focuses on the prognostic significance of cell cycle-regulating proteins in EOC. However, it is difficult to compare the results from different groups due to diverse methodologies and interpretations. Accordingly, researchers should establish standardized criteria for the interpretation of immunohistochemical results.

Epithelial ovarian cancer: the role of cell cycle genes in the different histotypes

Cancer is frequently considered to be a disease of the cell cycle; alterations in different families of cell cycle regulators cooperate in tumor development. Molecular analysis of human tumors has shown that cell cycle regulators are frequently mutated in human neoplasms, which underscores how important the maintenance of cell cycle commitment is in the prevention of human cancer. The regulatory pathways controlling cell cycle phases include several oncogenes and tumor suppressor genes which display a range of abnormalities with potential usefulness as markers of evolution or treatment response in epithelial ovarian cancer. This review summarizes the current knowledge about these aberrations in malignant tumors of the ovary. We sought to focus our attention on the genes involved in the development of tumors arising from the ovarian epithelium, which are the most common types of ovarian malignancies.

Cyclin E-associated kinase activity predicts response to platinum-based chemotherapy

PURPOSE

The role of cyclin E as a predictive marker of response to chemotherapy remains unknown. We have previously shown that deregulation of cyclin E in an ovarian tumor cell line model enhances cyclin E-associated kinase activity and sensitizes tumor cells to cisplatinum. We hypothesized that cyclin E deregulation would predict for responsiveness to platinum-based regimens in ovarian cancer patients.

EXPERIMENTAL DESIGN

Patients who met the following criteria were retrospectively identified from the institutional tumor bank records: (a) high-grade ovarian epithelial malignancy, (b) stage III/stage IV disease, (c) optimally debulked, (d) completed platinum-based therapy. Tumor samples were analyzed for cyclin E, p21, and p27 by Western blot analysis and assessed for cyclin E-associated kinase activity.

RESULTS

Seventy-five patients, who met the study criteria, were identified. Cyclin E protein levels did not correlate with cyclin E-cdk2 kinase activity (Spearman's rho, 0.07; P = 0.58). Cyclin E-associated kinase activity was the only significant predictive marker for response to platinum-based therapy, with higher response rates seen in patients with higher levels of activity (P = 0.045). Cyclin E protein levels did not predict for platinum sensitivity (P = 0.20). In contrast, cyclin E protein levels, but not cyclin E-associated kinase activity, was a significant predictor for freedom from recurrence (P = 0.01 and P = 0.25, respectively).

CONCLUSIONS

Cyclin E overexpression and cyclin E-associated kinase activity have distinct roles in predicting for response to chemotherapy and outcome in ovarian cancer patients. These results suggest a compartmentalization of cyclin E functions in the oncogenic process.

Interleukin-13 receptor alpha2 chain: a potential biomarker and molecular target for ovarian cancer therapy

BACKGROUND

Epithelial ovarian cancer demonstrates high mortality due to diagnosis at an advanced stage. In the search for a biomarker for early diagnosis and a target for therapy, the issue of whether interleukin-13 receptor (IL-13R), shown to be expressed on a variety of human cancers, is expressed in ovarian tumor samples was explored. In addition, whether this receptor serves as a biomarker and can be targeted by IL-13 cytotoxin was examined.

METHODS

IL-13R expression in 15 normal and 68 ovarian tumor tissue samples was determined by immunohistochemistry. Correlation between clinicopathologic features and IL-13R expression was analyzed. The efficacy of IL-13R-directed cytotoxin was determined in mice with subcutaneous, orthotopic, and peritoneal metastatic ovarian cancer.

RESULTS

Immunohistochemical analyses revealed that 83% of ovarian cancer specimens express IL-13Ralpha2, a high-affinity IL-13R subunit chain, whereas normal ovary samples expressed none or very low levels. The majority of clear cell ovarian carcinomas with the worst prognosis showed strong staining for IL-13Ralpha2. IL-13 cytotoxin was highly cytotoxic to the IGROV-1 ovarian cancer cell line in vitro, and it mediated significant antitumor activity against a xenografted tumor model. The antitumor effects were confirmed by treating orthotopically implanted or peritoneal metastatic ovarian tumors, which showed significant extension of survival in immunodeficient mice. IL-13 cytotoxin also prevented cachexia in treated mice. The soluble form of IL-13Ralpha2 was detected in the serum of mice with peritoneal metastasis, and the level decreased to baseline in the treated group.

CONCLUSIONS

IL-13Ralpha2 is a promising target for ovarian cancer therapy, and the soluble form of IL-13R may be a possible surrogate marker for disease monitoring.

Ovarian clear cell adenocarcinoma: a continuing enigma

Ovarian clear cell adenocarcinomas (OCCAs) account for <5% of all ovarian malignancies. Compared to other epithelial ovarian cancer (EOC) subtypes, when at an advanced stage, they are associated with a poorer prognosis and are relatively resistant to conventional platinum-based chemotherapy. By contrast, early-stage clear cell ovarian cancer carries a relatively good prognosis. Hence, there is a need to improve our understanding of its pathobiology in order to optimise currently available treatments and develop new therapeutic strategies. This review summarises the currently available literature regarding the pathogenesis of OCCA, its molecular genetic features and postulated molecular mechanisms that underlie its chemoresistant phenotype. Marked similarities with clear cell carcinomas of the kidney and endometrium have been noted by some investigators, raising interesting possibilities regarding novel therapeutic approaches. Unfortunately, most studies on OCCA have hitherto been hampered by insufficient sample sizes, leaving many key issues unresolved. It is envisaged that in the future, high-resolution genomic and gene-expression microarray studies incorporating larger sample sizes will lead to the characterisation of the key molecular players in OCCA biology, which may potentially lead to the identification of novel targets for therapeutic development.

Clinical and molecular differences between clear cell and papillary serous ovarian carcinoma

PURPOSE

The aim of the current study is to compare clear cell ovarian carcinoma (CCOC) and papillary serous ovarian carcinoma (PSOC) with respect to their clinical features and expression of different regulators of cell cycle, apoptosis, and chemoresistance.

EXPERIMENTAL DESIGN

Women with stage III CCOC (n = 9) and those with stage III, poorly differentiated PSOC (n = 21) seen between 1996 and 2000 and treated with cytoreductive surgery followed by paclitaxel and platinum chemotherapy were compared in their demographic features, tumor marker profile, surgical substage, results of cytoreductive surgery, thromboembolic complications, response to chemotherapy, and tumor recurrence. Tumor samples were compared in their expression of p53, Bcl(2), Bcl(x), Bax, p21, p-glycoprotein (PGP), multi-drug resistance-associated protein (MRP), lung resistance protein (LRP), and glutathione S-transferase (GST) using immunohistochemistry.

RESULTS

Women with CCOC had significantly lower mean preoperative CA-125 values, lower surgical substage, less expression of p53, and more expression of p21 than women with PSOC (P = 0.037, 0.012, 0.008, and 0.009, respectively). Women with CCOC had less ascites, smaller amount of residual tumor, higher incidence of thromboembolism, chemoresistance, more expression of Bcl(2), and less expression of PGP than women with PSOC (P = 0.067, 0.078, 0.108, 0.114, 0.091, and 0.118, respectively).

CONCLUSIONS

Women with CCOC exhibit certain clinical and molecular differences compared to stage- and grade-matched women with PSOC. Women with CCOC have a smaller tumor volume and manifest different expressions of p53, p21, and Bcl(2) than women with PSOC. Although further studies with larger number of patients are needed, our findings indicate that chemoresistance in CCOC is probably not p53-dependent.

Subcellular localization and protein levels of cyclin-dependent kinase inhibitor p27 independently predict for survival in epithelial ovarian cancer

PURPOSE

p27 protein is regarded as a valuable prognostic biomarker in cancer with a potential use as a molecular target. However, different methods of immunohistochemical assessment have yielded conflicting results. Here, we sought to determine the prognostic value of p27 in ovarian cancer using a novel method of compartmentalized in situ protein analysis.

EXPERIMENTAL DESIGN

A tissue array composed of 150 advanced stage ovarian cancers uniformly treated, with surgical debulking followed by platinum-paclitaxel combination chemotherapy, was constructed. For evaluation of p27 protein expression, we used an immunofluorescence-based method of automated in situ quantitative measurement of protein analysis [automated quantitative analysis (AQUA)].

RESULTS

The mean follow-up time of the patients was 34.3 months. Patients with low Fédération Internationale des Gynaecologistes et Obstetristes stage were more likely to have low nuclear p27 expression (P = 0.008). Low nuclear p27 expression was associated with improved 3-year overall survival (66% versus 20%, P = 0.0047) and disease-free survival (27% versus 12%, P = 0.022). In multivariable analysis, adjusting for well-characterized prognostic variables, low nuclear p27 expression level was the most significant prognostic factor for both disease-free and overall survival.

CONCLUSIONS

Our results indicate that quantitative assessment of nuclear p27 expression level by automated in situ quantitative analysis is a strong predictor for outcome in ovarian cancer.

Cell cycle genes in ovarian cancer: steps toward earlier diagnosis and novel therapies

Human malignant tumors are characterized by abnormal proliferation resulting from alterations in cell cycle-regulatory mechanisms. The regulatory pathways controlling cell cycle phases include several oncogenes and tumor suppressor genes that display a range of abnormalities with potential usefulness as markers of evolution or treatment response in ovarian cancer. This review summarizes the current knowledge about these aberrations in malignant tumors of the ovary. We sought to divide cell cycle-regulatory genes into four subgroups on the basis of their predominant role in a specific phase or during the transition between two phases of the cell cycle.

Cyclin E Amplification and Overexpression in Clear Cell Adenocarcinoma of the Ovary

OBJECTIVE

The purpose of this study is to compare DNA, mRNA and protein levels of the cyclin E between clear cell (CC) and serous (SC) ovarian carcinomas, and evaluate the relationship between cyclin E and p53 status.

METHOD

We examined the DNA, mRNA and protein levels of cyclin E and the protein level of p53 in 44 CCs and 39 SCs using microdissected tissues.

RESULTS

Relative cyclin E mRNA expression was significantly higher in CC (3.62, 95% CI, 2.24-4.99) than in SC (1.75, 95% CI, 1.05-2.45; p = 0.0098). The percentage of positive nuclear staining of cyclin E was significantly higher in CC (48.3, 95% CI, 40.4-56.1) than SC (25.3, 95% CI, 17.4-33.3; p = 0.0001). The mRNA and protein expression of cyclin E was significantly correlated (r = 0.66, p < 0.0001). However, the correlation between relative DNA copy number and relative mRNA expression was not significant (r = -0.063; p = 0.66). Percentage of positive nuclear staining of cyclin E was significantly higher in p53 positive cases (51.8, 95% CI, 40.0-63.5) than p53 negative cases (36.2, 95% CI, 28.2-44.2; p = 0.028).

CONCLUSIONS

Cyclin E expression is significantly higher in CC than in SC. Cyclin E expression is significantly related with p53 positivity.

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

Of all of the epithelial ovarian cancers, clear cell carcinoma (CCC) of the ovary has the worst prognosis. We applied the oligonucleotide array technique to identify genes generally involved in CCC. Of the approximately 12,600 genes that were analyzed, 28 were expressed significantly differently between four CCC and seven non-CCC cell lines. Among 16 up-regulated genes in CCC, we further investigated a transcription factor, hepatocyte nuclear factor-1 beta (HNF-1 beta). We validated up-regulation of HNF-1 beta in CCC in terms of both mRNA and protein level using real-time quantitative reverse transcriptase-polymerase chain reaction and immunoblotting. Immunohistochemical analysis of 83 surgically resected ovarian cancers showed that almost all CCC specimens (21 of 22 cases) had nuclear staining for HNF-1 beta, whereas most non-CCC specimens (60 of 61 cases) showed no immunostaining or only focal and faint staining in the nucleus. Furthermore, we investigated the significance of HNF-1 beta expression in CCC using RNA interference. The reduction of HNF-1 beta expression by RNA interference induced apoptotic cell death in ovarian CCC cells, which was confirmed by terminal dUTP nick-end labeling and fluorescence-activated cell-sorting analyses. Our results suggest that HNF-1 beta is not only an excellent CCC-specific molecular marker but also a molecular target for therapy of ovarian CCC.

Role of cell-cycle regulatory proteins in gynecological cancer

Human malignant tumors are characterized by abnormal proliferation resulting from alterations in cell-cycle regulatory mechanisms. This review summarizes the current knowledge about these aberrations in malignant tumors of the ovary, endometrium, cervix uteri, and vulva. The data indicate that analysis of single cell cycle stimulating or inhibiting proteins partly produces unexpected, apparently paradoxical results, and cell-cycle regulatory pathways should be regarded as a whole in order to identify the molecular mechanisms leading to abnormal tumor cell proliferation. For the papillomavirus (HPV)- associated cervical and vulvar carcinomas, the manifold effects of the viral oncogenes E6 and E7 on cell-cycle control are described.

P21WAF1, P27KIP1, TP53 and C-MYC analysis in 204 ovarian carcinomas treated with platinum-based regimens

BACKGROUND

The prognostic and predictive value of cell cycle regulatory proteins in ovarian cancer has not been established. We evaluated the clinical and biological significance of P21(WAF1), P27(KIP1), C-MYC, TP53 and Ki67 expressions in ovarian cancer patients.

MATERIALS AND METHODS

Immunohistochemical analysis was performed on 204 ovarian carcinomas of International Federation of Gynecology and Obstetrics (FIGO) stage IIB to IV treated with platinum-based chemotherapy. Multivariate analysis with Cox and logistic regression models was performed in the whole group, and in the TP53-negative and TP53-positive subgroups.

RESULTS

High P21(WAF1) labeling index (LI) was an independent positive predictor of platinum-sensitive response (P = 0.02). Overall survival was positively influenced by P21(WAF1) LI (P = 0.02) or by P21(WAF1) plus P27(KIP1) LI (P = 0.004) in the TP53-negative group only. Ki67 LI showed borderline association with disease-free survival (P = 0.05). Growth fraction was negatively associated with P21(WAF1) and P27(KIP1) indices in the TP53-negative group (P = 0.023 and 0.008, respectively), and these associations were borderline or lost in the TP53-positive group. Endometrioid and clear cell carcinomas differed from other carcinomas by having a low incidence of TP53 accumulation, a high incidence of C-MYC overexpression (70%) and a low median Ki67 LI (all with P <0.001).

CONCLUSIONS

We have shown an independent predictive value of P21(WAF1) LI in ovarian carcinoma patients. The prognostic value of P21(WAF1) and P21(WAF1) plus P27(KIP1) LI was determined by TP53 status. A high frequency of C-MYC overexpression in endometrioid and clear cell carcinomas may suggest its role in the development of these tumor types.

Immunohistochemical expression of cyclin E in endometrial adenocarcinoma (endometrioid type) and its clinicopathological significance

PURPOSE

Cyclin E is known as a G1-S phase regulatory protein and its abnormal expression has been implicated in cellular proliferation. This study aimed to investigate the correlation of cyclin E expression with tumorigenesis of the endometrium, proliferative activity, and clinicopathological features of endometrial adenocarcinoma.

METHODS

Immunohistochemical staining for cyclin E in addition to cyclin-dependent kinase 2 (cdk2), Ki67, p27, and p53 was performed by the labeled streptavidin-biotin method on formalin-fixed, paraffin-embedded tissues of normal endometria (20 cases), endometrial hyperplasias (20 cases), and endometrial adenocarcinomas (endometrioid type) (127 cases). Positive staining was expressed as a labeling index (LI) based on percentages of positive nuclei in tumor cells.

RESULTS

Immunohistochemistry showed that the nuclei of the cells were positive for cyclin E. Both proliferative and secretory endometria, and endometrial hyperplasia regardless of type were negligible for cyclin E expression. The expression in normal endometrium and hyperplasia was significantly less than that in endometrial adenocarcinomas (P<0.0001). LIs of cyclin E in well-differentiated, moderately differentiated, and poorly differentiated endometrial adenocarcinomas were 31.5+/-33.3%, 37.8+/-31.9%, and 51.1+/-30.8%, respectively. Cyclin E expression increased significantly more in histological grades. The LI of cyclin E in carcinoma was positively correlated with that of cdk2, Ki67, and p53 but not with p27. The cyclin E expression was correlated with myometrial invasion and lymph-vascular space involvement, but not with FIGO stage, lymph node metastasis, coexisting endometrial hyperplasia, estrogen receptor, progesterone receptor, and menopause.

CONCLUSION

Cyclin E as a complex with cdk2 is associated with carcinogenesis and disease progression in endometrial adenocarcinoma, and might be a prognostic indicator of endometrial adenocarcinoma.

Overexpression of c-fos in Helicobacter pylori-induced gastric precancerosis of Mongolian gerbil

AIM: To explore dysregulation of c-fos in several human malignancies, and to further investigate the role of c-fos in Helicobacter pylori (H. pylori)-induced gastric precancerosis.

METHODS: Four-week-old male Mongolian gerbils were employed in the study. 0.5 mL 1 × 10⁸ cfu·L^-1 suspension of H. pylori NCTC 11637 in Brucella broth were inoculated orally into 20 Mongolian gerbils. Another 20 gerbils were inoculated with Brucella broth as controls. 10 of the infected gerbils and 10 of the non-infected control gerbils were sacrificed at 25 and 45 weeks after infection. The stomach of each gerbil was removed and opened for macroscopic observation. The expression of c-fos was analyzed by RT-PCR and immunohistochemical studies in H. pylori-induced gastric precancerosis of Mongolian gerbil. Half of each gastric antrum mucosa was dissected for RNA isolation and RT-PCR. β-actin was used as the housekeeping gene and amplified with c-fos as contrast. PCR products of c-fos were analyzed by gel image system and the level of c-fos was reflected with the ratio of c-fos/β-actin. The immunostaining for c-fos was conducted using monoclonal antibody of c-fos and the StreptAvidin-Biotin-enzyme Complex kit.

RESULTS: H. pylori was constantly found in all infected animals in this study. After infection of H. Pylori for 25 weeks, ulcers were observed in the antral and the body of stomach of 60% infected animals (6/10). Histological examination showed that all animals developed severe inflammation, especially in the area close to ulcers, and multifocal lymphoid follicles appeared in the lamina propria and submucosa. After infection of H. Pylori for 45 weeks, severe atrophic gastritis in all infected animals, intestinal metaplasia in 80% infected animals (8/10) and dysplasia in 60% infected animals (6/10) could be observed. C-fos mRNA levels were significantly higher after infection of H. pylori for 25 weeks (1.84 ± 0.79), and for 45 weeks (1.59 ± 0.37) than those in control-animals (0.74 ± 0.22, P < 0.01). C-fos mRNA levels were increased 2.5-fold by 25th week (P < 0.01) and 2.1-fold by 45th week (P < 0.01) in precancerosis induced by H. pylori, when compared with normal gastric epithelium of Mongolian gerbil. Immunohistochemical staining revealed exclusive nuclear staining of c-fos. Furthermore, there was a sequential increase in c-fos positive cells from normal epithelium to precancerosis.

CONCLUSION: The study suggested that overexpression of c-fos occurs relatively early in gastric tumorigenesis in this precancerosis model induced by H. pylori.

A review of p53 expression and mutation in human benign, low malignant potential, and invasive epithelial ovarian tumors

BACKGROUND

In the current study, the authors present pooled data from studies that investigated p53 protein expression and/or mutation in human epithelial ovarian tumors.

METHODS

The English literature in the MEDLINE, PubMed, and Ingenta databases was searched to the end of the year 2000 to identify relevant studies. Data were pooled across eligible studies, and the prevalence of p53 expression and mutation among benign, low malignant potential (LMP), and invasive tumors was determined. Prevalence estimates by tumor histology, International Federation of Gynecology and Obstetrics (FIGO) stage, and grade also were calculated.

RESULTS

The pooled prevalence estimate for p53 overexpression among epithelial ovarian carcinomas was 51% (95% confidence intervals [95% CI], 50-53%) compared with 17% (95% CI, 15-20%) among LMP tumors and 7% (95% CI, 5-10%) among benign tumors. p53 mutation prevalence estimates were 45% (95% CI, 42-47%), 5% (95% CI, 2-9%), and 1% (95% CI, 0-5%), respectively, for invasive, LMP, and benign tumors. The prevalence of these p53 abnormalities was found to be associated positively with increasing tumor grade and stage. Differences based on histologic subtype also were found.

CONCLUSIONS

Although these pooled estimates might appear to offer support for various hypotheses regarding the role of p53 in ovarian carcinoma, the limitations inherent in these data hamper the interpretation of the significance of any of the findings. Future studies will require innovative methods to address the limitations of many previous investigations and more comprehensive investigation into defective tumor suppression mechanisms.

The combined evaluation of p27Kip1 and Ki-67 expression provides independent information on overall survival of ovarian carcinoma patients

OBJECTIVE

Considering the limited and controversial information on the significance of the cyclin-dependent kinase inhibitor p27Kip1 in ovarian cancer, we conducted a retrospective investigation to clarify the relationships of this protein to proliferation rate, clinicopathologic variables, and prognosis of epithelial ovarian tumors.

METHODS

Paraffin-embedded tissue from 43 ovarian tumors of low malignant potential (LMP) and 80 primary ovarian adenocarcinomas was stained immunohistochemically for p27Kip1, Ki-67 antigen (a marker of cell proliferation), and p53 protein. Expression of these markers was correlated with clinicopathologic features and with overall survival of patients with adenocarcinomas.

RESULTS

p27Kip1 levels were significantly higher in LMP tumors as well as in low-grade, early-stage, slowly proliferating adenocarcinomas and those associated with minimal residual disease (P < 0.001). Decreased p27Kip1 expression was related to poor overall survival on its own (P = 0.0304) and, when combined, to increased proliferation rate (P = 0.0232). More importantly, in multivariate analysis, p27Kip1/Ki-67 status was independently related to survival (P = 0.040) along with histologic type and FIGO stage.

CONCLUSION

Decreased p27Kip1 expression is related to several clinicopathologic indicators of aggressiveness in ovarian adenocarcinomas and is a major player in cell cycle control in these neoplasms. On the contrary, deregulation of the protein does not seem to participate in the pathogenesis of LMP tumors. Furthermore, combined p27Kip1/Ki-67 expression is a better prognostic marker than expression of p27Kip1 or Ki-67 alone and supplements the prognostic information gained from traditional prognosticators.

Recent advances in immunohistochemistry in gynaecological pathology

Recent years have witnessed significant developments in the use of immunohistochemistry in diagnostic gynaecological pathology. This review details the most significant of these. In ovarian pathology, differential cytokeratin staining (CK7 and 20) assists in distinguishing between a primary ovarian adenocarcinoma and a metastatic adenocarcinoma, especially of colorectal origin. The development of markers characteristic of ovarian sex cord-stromal tumours (especially alpha-inhibin) facilitates diagnosis of these neoplasms which is often difficult by morphology alone due to the wide differential diagnosis. In the uterus, the distinction between a primary endometrial and endocervical adenocarcinoma may be facilitated by use of a small panel of antibodies, including CEA, ER and vimentin. Newly developed antibodies such as CD10 and h-caldesmon may be of use in the diagnosis of uterine mesenchymal lesions, especially in the distinction between endometrial stromal and smooth muscle lesions. Proliferation markers, such as MIB1, are of value in the cervix in the diagnosis of preinvasive squamous and glandular lesions. Recent studies have shown that cervical adenoma malignum exhibits a gastric phenotype. Advances have also been made in trophoblastic disease with the development of antibodies reactive against trophoblast such as alpha-inhibin, mel-Cam and p57. A newly developed monoclonal antibody HMGIC which is expressed in vulvovaginal aggressive angiomyxoma may prove to be of value in the often difficult distinction of this lesion from its histological mimics.

Overexpression of cyclin E in Mongolian gerbil with Helicobacter pylori- induced gastric precancerosis

AIM: To explore dysregulation of cyclin E in malignancies, and to further investigate the role of cyclin E in Helicobacter pylori (H. pylori)-induced gastric precancerosis.

METHODS: Four-week-old specific pathogen-free male Mongolian gerbils were employed in the study. 0.5 mL 1 × 10⁸ cfu·L^-1 suspension of H. pylori NTCC11637 in Brucella broth was inoculated orally into each of 20 Mongolian gerbils, and a further 20 gerbils were inoculated with Brucella broth as controls. 10 of the infected gerbils and 10 of the non-infected control gerbils were sacrificed at 25, 45 wk after infection. The expression of cyclin E was analyzed by RT-PCR and immunohistochemical studies with monoclonal antibody to cyclin E in Mongolian gerbil of H. pylori-induced gastric precancerosis.

RESULTS: H. pylori was constantly detected in all infected animals throughout the study. At 25 wk after infection of H. pylori. ulcers were observed in the antral and body of stomach (n = 6). Histological examination showed that all animals developed severe inflammation and multifocal lymphoid follicles appeared in the lamina propria and submucosa of gastric antrum. At 45 wk after infection of H. pylori, severe atrophic gastritis (n = 10). intestinal metaplasia (n = 8) and dysplasia (n = 6) could be observed. Cyclin E mRNA levels were significantly more at 25 wk after infection of H. pylori (1.27 ± 0.26), and at 45 wk after infection of H. pylori ( 1.82 ± 0.39) than control-animals (0.59 ± 0.20,P < 0.01); cyclin E mRNA levels were evaluated by 2.2-fold at 25 wk (P < 0.01) and 3.1-fold at 45 wk (P < 0.01) precancerosis induced by H. pylori, when compared with control gastric epithelium of Mongolian gerbil. Immunohistochemical staining revealed exclusive nuclear staining of cyclin E. Furthermore, there was a sequential increase in cyclin E positive cells from normal epithelium to precancerosis.

CONCLUSION: Overexpression of cyclin E occurs relatively early in gastric tumorigenesis in this model.

Expression of cell cycle proteins in ovarian carcinoma cells in serous effusions-biological and prognostic implications

OBJECTIVE

The aim of this study was to investigate the expression of cell cycle proteins in ovarian carcinoma cells in serous effusions and respective solid tumors.

METHODS

Fifty-five malignant effusions and 38 tumors (20 primary, 18 metastatic) were immunohistochemically stained for cyclin A, p27(kip1), and Ki-67. Staining extent (0-100% cells) and intensity (0-3 scale) were scored. Cyclin A and p27(kip1) expression was additionally studied in 29 malignant effusions using immunoblotting. Immunohistochemistry results in effusions were evaluated for possible association with clinicopathologic parameters.

RESULTS

Nuclear immunoreactivity for all markers was detected on carcinoma cells in the majority of effusions using immunohistochemistry. Similarly, immunoblotting showed the presence of cyclin A and p27(kip1) in 29/29 and 25/29 specimens, respectively. Intense (3) immunoreactivity for Ki-67 was detected more often in peritoneal effusions, compared with those of pleural location (P = 0.036). Staining in primary and metastatic lesions was generally comparable to that of tumor cells in effusions. Staining for p27(kip1) was more diffuse in effusion specimens obtained prior to the institution of chemotherapy (P = 0.042). In an analysis of all effusions, an association was observed between the number of cells that were immunoreactive for Ki-67, cyclin A, and p27(kip1) (cyclin A-Ki-67: P = 0.008; p27(kip1)-Ki-67: P = 0.019; cyclin A-p27(kip1): P = 0.032). In survival analysis, the presence of more diffuse (P = 0.042) and intense (P = 0.019) staining for cyclin A correlated with prolonged overall survival.

CONCLUSIONS

The expression of the studied cell cycle markers does not differ markedly between ovarian carcinoma cells in the pleural and peritoneal cavity, supporting our previous studies of several metastasis-associated molecules. The presence of cyclin-A-positive cell populations is associated with a more favorable disease outcome, possibly due to the targeting of proliferating cells by chemotherapeutic agents. However, the decline in the fraction of p27(kip1)-positive cells in posttreatment specimens may point to additional mechanisms involved in this selection.

High cyclin E and low p27/Kip1 expressions are potentially poor prognostic factors in lung adenocarcinoma patients

Cyclin E is an important regulator of entry into the S phase of the cell cycle. p27/Kip1 (p27) binds to cyclin E/Cdk2 complex and negatively regulates cell proliferation. We immunohistochemically examined the expression of cyclin E and p27 in 98 cases of resected lung adenocarcinoma to evaluate the prognostic significance of cyclin E and p27. Cyclin E was expressed in 16 cases (16%), and p27 was expressed in 41 cases (42%). Using Kaplan-Meier survival analysis, patients with cyclin E positive (P=0.0017) and p27 negative (P=0.011), both individually and in combination (P<0.0001), had a worse prognosis. We also analyzed the relationship of these findings to clinicopathological parameters, which revealed that cyclin E-positive, p27-negative cases had a higher Ki67 expression (P=0.012) and a higher rate of lymph node metastasis (P=0.0078) than other groups. Our results suggested that cyclin E over expression, in association with p27 reduction in particular, may potentially be a poor prognostic factor in lung adenocarcinoma patients. However, to verify the prognostic significance of these factors, a multivariate analysis of a larger number of patients should be undertaken.

Possible associations among expression of p14(ARF), p16(INK4a), p21(WAF1/CIP1), p27(KIP1), and p53 accumulation and the balance of apoptosis and cell proliferation in ovarian carcinomas

BACKGROUND

Although there are several reports of changes in expression of cyclin-dependent kinase inhibitors in ovarian carcinomas, little is known about their associations with tissue kinetics in the various histologic subtypes.

METHODS

In total, 131 carcinomas were immunohistochemically investigated for expression of p14(ARF) (p14), p16(INK4a) (p16), p21(WAF1/Cip1) (p21), and p27(Kip1) (p27). The results also were compared with data for apoptosis, cell proliferation, p53 status, and survival. Western blot and mRNA analyses were conducted on 35 malignant ovarian tumor samples.

RESULTS

Significant differences in tissue kinetics determined by ratios of apoptotic relative to mitotic indices were observed among histologic subtypes of ovarian carcinomas, showing a shift toward predominance of cell proliferation in serous and cell deletion in clear cell types. The expression of p16, p21, p27, and p53 was associated closely with changes in cell proliferation rather than apoptosis and survival, dependent on the subtype. Positivity for p16 and p21 in the Western blot assay was significantly related to the results for immunohistochemical but not mRNA analyses, indicating possible posttranscriptional regulation of these genes.

CONCLUSIONS

The findings indicate that the several cyclin-dependent kinase inhibitors investigated are expressed differently among histologic subtypes of ovarian carcinomas, associated with differences in tissue kinetics and the balance of apoptosis and cell proliferation.

p21 and p53 in ovarian carcinoma: their combined staining is more valuable than either alone

BACKGROUND

Mutations in p53 are the most common genetic alterations in human malignancies. Expression of its protein product has been linked to decreased survival rate in ovarian carcinoma. Less is known about the importance of p21 expression. The purpose of this study was to determine the value of the combination of p21 and p53 expression in patients with epithelial ovarian malignancies.

METHODS

One hundred three consecutive patients with epithelial ovarian carcinoma were studied using snap-frozen tissue specimens. Immunohistochemical staining utilizing the pAb1801 monoclonal antibody to p53 and NCL-WAF-1 monoclonal antibody to p21 was performed. Image analysis was used to determine whether nuclear staining for either antibody was present. In addition to p21 and p53, International Federation of Gynecology and Obstetrics stage, grade, histology, level of cytoreduction, and DNA index were analyzed as prognostic factors. Univariate and multivariate analyses was performed.

RESULTS

One hundred three patients were observed for more than 5 years. Immunohistochemical staining for p21 and p53 were significantly inversely related (P = 0.041). Among the patients whose tumors showed p21 staining but no p53 staining, there were no recurrences and all patients were alive at 5-year follow-up. The 5-year survival rate for these patients was significantly better than for the patients with other combinations of p21/p53 staining (P < 0.0001). The DNA index between these 2 groups was not significantly different (P = 0.057). Multivariate analysis shows the combination of p21 and p53 (P = 0.013) staining to be more valuable as a prognostic indicator than either p53 (P = 0.015) or p21 (P = 0.5) alone.

CONCLUSIONS

This study confirms the importance of the combination of p21 and p53 nuclear staining in patients with ovarian carcinoma. Cox regression analysis revealed combination of p21 positive and p53 negative to be a better independent indicator of prognosis and survival in patients with ovarian carcinoma than either p21 or p53 alone.

Expression of cell cycle regulators p57(KIP2), cyclin D1, and cyclin E in epithelial ovarian tumors and survival

The search for new prognostic indicators is especially important in the diagnosis and treatment of ovarian cancer because clinicopathologic criteria currently used to predict survival are largely inadequate. We examined 2 groups of patients with epithelial ovarian cancer, 1 group of long-term survivors (>5 years), and 1 group of short-term survivors (<2 years) for levels of expression of the cell cycle regulators p57(KIP2), cyclin D1, and cyclin E and their relationship with survival. Our findings show that p57(KIP2) is not associated with prognosis, in contrast to p27(KIP1) expression, which is previously shown to be positively associated with long-term survival in univariate analysis (P =.001). Cyclin E expression, in contrast to cyclin D1 expression, is marginally associated with short-term survival in univariate analysis for a group of 53 women. Among the short-term survivors, 15 (65%) of 23 were positive for cyclin E expression, compared with only 11 (37%) of 30 long-term survivors (P = 0.054). This association remained significant (P =.04) in a logistic regression analysis adjusted simultaneously for performance status and extent of residual disease, the 2 strongest predictors of survival in our study. We also found a significant difference in the frequency of the cyclin E staining pattern between nonserous and serous ovarian tumor subtypes (P =.0002). Immunostaining for levels of cyclin E and p27(KIP1) expression may have potential as prognostic markers in the management of ovarian cancer.

Absence of estrogen receptor-alpha expression in human ovarian clear cell adenocarcinoma compared with ovarian serous, endometrioid, and mucinous adenocarcinoma

The mechanism that regulates growth in ovarian clear cell adenocarcinoma (CCA) is not well understood. A high incidence of concurrent endometriosis with CCA may indicate that estrogen is a growth promotor in CCA. To determine estrogen as a growth promotor, the authors investigated the presence or absence of estrogen receptor-alpha (ER-alpha), ER-beta, progesterone receptor, and dioxin receptor (i.e., aromatic hydrocarbon receptor) in clinically resected ovarian CCA, serous adenocarcinoma (SAC), endometrioid adenocarcinoma (EAC), and mucinous adenocarcinoma (MAC) specimens using an immunohistochemical method. Expression of ER-alpha and ER-beta messenger ribonucleic acid was examined by reverse transcription-polymerase chain reaction in three established CCA cell lines: KK, RMG-1, and HAC-II. None of the surgically resected CCA and CCA cell lines showed positive staining for ER-alpha. Conversely, 97.2% of SACs, 100% of EACs, and 70% of MACs showed positive nuclear staining for ER-alpha (p < 0.001). Conversely, positive ER-beta staining for CCA (39.3%) was similar to that of SAC (41.7%) and MAC (30.0%). EAC (75%) showed a higher expression of ER-beta (p < 0.02). Progesterone receptor was detected in only 10.7% of CCA, compared with SAC and EAC (SAC, 86.1%; EAC, 91.7%; p < 0.01). Aromatic hydrocarbon receptor was detected in all histologic types at an incidence of approximately 50% to 60%. Messenger ribonucleic acid of ER-alpha and ER-beta was not detected in the three CCA cell lines. These findings indicate biologic characteristics that distinguish CCA from other types of ovarian epithelial cancer.

The role of p27 in endometrial carcinoma

OBJECTIVE

The cyclin-dependent kinase inhibitor p27 has been shown to mediate cell growth arrest in response to various environmental stimuli. p27 protein levels have shown prognostic value in several different types of cancer. We examined the prognostic value of p27 protein expression in endometrial cancer, the most common gynecologic malignancy.

METHODS

A total of 95 paraffin-embedded tumor blocks were obtained and stained via immunohistochemical techniques with a monoclonal antibody against p27. Ten high-power fields were evaluated per slide with at least 1000 cells per slide and two slides per specimen evaluated by two reviewers for nuclear and cytoplasmic staining. The specimens were evaluated for associations with age, stage, grade, and histology. Statistical analysis was performed using the Student t test, chi(2) Kaplan-Meier, and likelihood ratios to assess the data and to generate P values.

RESULTS

A total of 91 patients met inclusion criteria for statistical analysis. Fifty-three patients were stage I, 13 stage II, 14 stage III and 11 stage IV with a positive stain (>50% of cells) for p27 obtained in 32.1, 23.1, 35.7, and 36.4%, respectively (Student t test P = 0.77). Survival data were available on 24 advanced stage patients. p27 protein immunostaining showed no association with patient survival. We also found no association of p27 staining with age or histology. Notably, we found a trend in increasing staining with increase in grade, particularly with stage I patients. Also, there was an association of the nuclear and cytoplasmic staining and stage (P = 0.05), but it had no correlation with patient survival.

CONCLUSION

Our study showed decreased p27 protein staining in endometrial cancers compared to normal endometrial cells. We found that p27 protein staining shows no association with stage, age, or histology and is not prognostic for survival in advanced endometrial cancers. However, there may be a trend associated with increased p27 protein staining with advanced grades of tumors.