The concurrent expression of p27(kip1) and cyclin D1 in epithelial ovarian tumors

Inhibition of CDK4/6 as Therapeutic Approach for Ovarian Cancer Patients: Current Evidences and Future Perspectives

Simple Summary

Altered regulation of the cell cycle is a hallmark of cancer. The recent clinical success of the inhibitors of CDK4 and CDK6 has convincingly demonstrated that targeting cell cycle components may represent an effective anti-cancer strategy, at least in some cancer types. However, possible applications of CDK4/6 inhibitors in patients with ovarian cancer is still under evaluation. Here, we describe the possible biological role of CDK4 and CDK6 complexes in ovarian cancer and provide the rationale for the use of CDK4/6 inhibitors in this pathology, alone or in combination with other drugs. This review, coupling basic, preclinical and clinical research studies, could be of great translational value for investigators attempting to design new clinical trials for the better management of ovarian cancer patients.

Abstract

Alterations in components of the cell-cycle machinery are present in essentially all tumor types. In particular, molecular alterations resulting in dysregulation of the G1 to S phase transition have been observed in almost all human tumors, including ovarian cancer. These alterations have been identified as potential therapeutic targets in several cancer types, thereby stimulating the development of small molecule inhibitors of the cyclin dependent kinases. Among these, CDK4 and CDK6 inhibitors confirmed in clinical trials that CDKs might indeed represent valid therapeutic targets in, at least some, types of cancer. CDK4 and CDK6 inhibitors are now used in clinic for the treatment of patients with estrogen receptor positive metastatic breast cancer and their clinical use is being tested in many other cancer types, alone or in combination with other agents. Here, we review the role of CDK4 and CDK6 complexes in ovarian cancer and propose the possible use of their inhibitors in the treatment of ovarian cancer patients with different types and stages of disease.

Protein Network Analysis of the Fifth Chromosome of Zebrafish

In the past 20 years, zebrafish has gradually become an important animal model for studying the function of human genes. At the same time, identification of zebrafish reference genome sequences and >10,000 protein-coding genes indicates that they are at least 75% homologous to human genes, further validating its utility as a research model for growth and developments (GDs). However, the molecular mechanism of zebrafish GDs has almost no molecular interactions, so a protein-protein interaction (PPI) network is highly desirable. The project extracted 58 genes on the fifth chromosome of the model organism, and studied and modeled its GDs mechanisms, which encompassed 296 interactions between the 58 proteins involved in GDs. This includes not only accurate predictions of PPI but also those molecular interactions collected from the literature and experimentally derived. These molecules then interact, modularize, look for central genes, analyze, and predict their GDs processes, and hope to help scholars study the process of GDs, providing hypotheses and help.

Systematic module approach identifies altered genes and pathways in four types of ovarian cancer

The present study aimed to identify altered genes and pathways associated with four histotypes of ovarian cancer, according to the systematic tracking of dysregulated modules of reweighted protein-protein interaction (PPI) networks. Firstly, the PPI network and gene expression data were initially integrated to infer and reweight normal ovarian and four types of ovarian cancer (endometrioid, serous, mucinous and clear cell carcinoma) PPI networks based on Spearman's correlation coefficient. Secondly, modules in the PPI network were mined using a clique-merging algorithm and the differential modules were identified through maximum weight bipartite matching. Finally, the gene compositions in the altered modules were analyzed, and pathway functional enrichment analyses for disrupted module genes were performed. In five conditional-specific networks, universal alterations in gene correlations were revealed, which leads to the differential correlation density among disrupted module pairs. The analyses revealed 28, 133, 139 and 33 altered modules in endometrioid, serous, mucinous and clear cell carcinoma, respectively. Gene composition analyses of the disrupted modules revealed five common genes (mitogen-activated protein kinase 1, phosphoinositide 3-kinase-encoding catalytic 110-KDα, AKT serine/threonine kinase 1, cyclin D1 and tumor protein P53) across the four subtypes of ovarian cancer. In addition, pathway enrichment analysis confirmed one common pathway (pathways in cancer), in the four histotypes. This systematic module approach successfully identified altered genes and pathways in the four types of ovarian cancer. The extensive differences of gene correlations result in dysfunctional modules, and the coordinated disruption of these modules contributes to the development and progression of ovarian cancer.

Survivin and cycline D1 expressions are associated with malignant potential in mucinous ovarian neoplasms

The most prevalent malignant ovarian neoplasms are epithelial ovarian cancers which is the most common cause of death among all gynecologic malignancies and a result of complex interaction of multiple oncogenes and tumor suppressor genes. The aim of this study was to evaluate expression of survivin and cycline D1 biomarkers in mucinous ovarian neoplasms and their correlations with clinicopathological variables in mucinous ovarian cancers. We analyzed pathological specimens of 98 patients with benign (n = 34), borderline (n = 22) and malignant (n = 42) mucinous ovarian neoplasms. Immunohistochemical analysis was performed on formalin-fixed paraffin-embedded specimens. Immunohistochemical analysis revealed that survivin and cyclin D1 expressions were located primarily in the nucleus of ovarian tumor cells and relatively weaker cytoplasmic staining. Survivin expression was significantly higher in malignant tumors (88.1 %) than those found in borderline (18.2 %) and benign tumors (8.8 %) (p < 0.001). Similarly, higher cyclin D1 expression was observed in malignant tumors (100 %) compared to borderline (36.4 %) and benign tumors (5.9 %) (p < 0.001). Expression of all biomarkers analyzed significantly and gradually increased from benign to borderline and borderline to malignant mucinous tumors. In terms of clinicopathological variables, tumor grade, FIGO stage and lymph node methastasis were associated with the expression of both biomarkers. Whereas age exhibited no different correlations in mucinous ovarian cancers. The expressions of survivin and cycline D1 are positively correlated with the malignant potential of mucinous ovarian neoplasms.

Gankyrin facilitates follicle-stimulating hormone-driven ovarian cancer cell proliferation through the PI3K/AKT/HIF-1α/cyclin D1 pathway

Gankyrin is a regulatory subunit of the 26kD proteasome complex. As a novel oncoprotein, gankyrin is expressed aberrantly in cancers from several different sites and has been shown to contribute to oncogenesis in endometrial and cervical carcinomas. Neither gankyrin's contribution to the development of epithelial ovarian cancer nor its interaction with follicle-stimulating hormone (FSH)-driven proliferation in ovarian cancer has been studied. Here we have found that gankyrin is overexpressed in ovarian cancers compared with benign ovarian cystadenomas and that gankyrin regulates FSH upregulation of cyclin D1. Importantly, gankyrin regulates PI3K/AKT signaling by downregulating PTEN. Prolonged AKT activation by FSH stimulation of the FSH receptor (FSHR) promotes gankyrin expression, which, in turn, enhances AKT activation by inhibiting PTEN. Overexpression of gankyrin decreases hypoxia inducible factor-1α (HIF-1α) protein levels, but has little effect on HIF-1α mRNA levels, which could be attributed to gankyrin mediating HIF-1α protein stability via the ubiquitin-proteasome pathway. Reduction in HIF-1α protein stability led to attenuation of the binding with cyclin D1 promoter, resulted in abolishment of the negative regulation of cyclin D1 by HIF-1α, which promotes proliferation of ovarian cancer cells. Our results document that gankyrin regulates HIF-1α protein stability and cyclin D1 expression, ultimately mediating FSH-driven ovarian cancer cell proliferation.

Investigation of the hub genes and related mechanism in ovarian cancer via bioinformatics analysis

Background

Ovarian cancer is a cancerous growth arising from the ovary.

Objective

This study was aimed to explore the molecular mechanism of the development and progression of the ovarian cancer.

Methods

We first identified the differentially expressed genes (DEGs) between the ovarian cancer samples and the healthy controls by analyzing the GSE14407 affymetrix microarray data, and then the functional enrichments of the DEGs were investigated. Furthermore, we constructed the protein-protein interaction network of the DEGs using the STRING online tools to find the genes which might play important roles in the progression of ovarian cancer. In addition, we performed the enrichment analysis to the PPI network.

Results

Our study screened 659 DEGs, including 77 up- and 582 down-regulated genes. These DEGs were enriched in pathways such as Cell cycle, p53 signaling pathway, Pathways in cancer and Drug metabolism. CCNE1, CCNB2 and CYP3A5 were the significant genes identified from these pathways. Protein-protein interaction (PPI) network was constructed and network Module A was found closely associated with ovarian cancer. Hub nodes such as VEGFA, CALM1, BIRC5 and POLD1 were found in the PPI network. Module A was related to biological processes such as mitotic cell cycle, cell cycle, nuclear division, and pathways namely Cell cycle, Oocyte meiosis and p53 signaling pathway.

Conclusions

It indicated that ovarian cancer was closely associated to the dysregulation of p53 signaling pathway, drug metabolism, tyrosine metabolism and cell cycle. Besides, we also predicted genes such as CCNE1, CCNB2, CYP3A5 and VEGFA might be target genes for diagnosing the ovarian cancer.

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.

Organ differences in the impact of p27(kip1) deficiency on carcinogenesis induced by N-methyl-N-nitrosourea

To evaluate the impact of p27 on carcinogenesis in various organs, N-methyl-N-nitrosourea (MNU), a direct-acting alkylating agent, was given to p27 knock-out mice. Groups of 20-40 male and female mice with null, hetero- or wild-type p27 alleles were given drinking water containing 240 ppm MNU or distilled water every other week for five cycles. The incidence and multiplicity of the induced proliferative lesions were then histologically evaluated at weeks 14 and 20. MNU treatment induced various lesions including squamous hyperplasia and squamous cell carcinoma in the forestomach, atypical hyperplasia and adenocarcinomas in the fundic and pyloric glands, adenomas and adenocarcinomas in the duodenum, malignant lymphomas in the thymus, liver, kidney and spleen and alveolar hyperplasia, adenomas, adenocarcinomas and malignant lymphomas in the lung. Although the incidences of the lesions in the forestomach, fundic and pyloric glands did not differ among the p27 genotypes, those of alveolar hyperplasia of the lung and malignant lymphoma of the thymus were significantly increased in p27-null males as compared with both wild- and hetero-type animals. Moreover, in both p27(+/+) and p27(+/-) cases, the rates for p27-positive cells were obviously increased in proliferative lesions of the pyloric gland and the lung. However, an increased rate of p27-positive cells was not observed in malignant lymphoma of the thymus. These findings suggest that p27 does not control the cell cycle equally in all organs affected by MNU-induced carcinogenesis.

Nuclear P27 expression in benign, borderline (LMP) and invasive tumors of the ovary and its association with prognosis: a gynecologic oncology group study

OBJECTIVE

Nuclear p27 expression was examined in non-invasive and invasive ovarian tumors from a cross-sectional study, and clinical relevance of p27 was evaluated in the primary tumors from women participating in two randomized phase III treatment trials.

METHODS

An immunohistochemistry assay was used to detect p27 in formalin-fixed paraffin-embedded ovarian tumors from 3 distinct sources.

RESULTS

Among the initial 91 ovarian tumors tested, low p27 expression (<50% positive cells) was observed in 5.4% of non-invasive tumors versus 42.6% of invasive tumors (p<0.001). In 145 ovarian cancers with high-risk early stage disease, 16.5% exhibited low p27 expression, and categorized p27 was not associated with age, race, or performance status. Low expression of p27 was common in poorly differentiated tumors (35.7%) compared to moderately (15.0%) and well (9.5%) differentiated tumors (p=0.024) and rare in clear cell carcinomas (2.4%) compared to other histologies (p=0.014). In the 139 cancers with advanced disease, 60% displayed low p27 expression, and categorized p27 expression was not associated with age, race, performance status, tumor grade, histologic subtype, measurable disease status or survival. Exploratory analyses revealed an association of cyclin E to p27 ratio >1.0 with an increased risk of death (hazard ratio=1.53; p=0.017).

CONCLUSIONS

Low p27 expression could be associated with malignant transformation of the ovarian epithelium and FIGO stage. A cyclin E to p27 ratio >1.0 may be associated with shorter survival in these patients. Further study is required to confirm the trend for increased recurrences with low p27 expression in early stage disease.

MiR-221 and MiR-222 alterations in sporadic ovarian carcinoma: Relationship to CDKN1B, CDKNIC and overall survival

MicroRNAs are often aberrantly expressed in human neoplasms and are postulated to play a role in neoplastic initiation and progression. miR-221 and miR-222 negatively regulate expression of CDKN1B (p27) and CDKN1C (p57), two cell cycle regulators expressed in ovarian surface epithelium and down-regulated in ovarian carcinomas. We characterized miR-221 and miR-222 expression in 49 sporadic high grade ovarian carcinomas and determined whether somatic mutation or epigenetic alterations explained the differences in expression of these miRNAs. We correlated these findings with protein expression of CDKN1B and CDKN1C as assessed by immunohistochemistry. Expression of miR-221 and miR-222 were closely correlated with each other (P = 0.0001). Interestingly, a lower ratio of miR-221 to miR-222 expression was significantly correlated with worse overall survival (P = 0.01) and remained a significant predictor of overall survival in multivariate analysis using the covariate adequacy of surgical cytoreduction (P = 0.03). Higher miR-222 and miR-221 expression were significantly associated with decreased CDKN1C expression (P = 0.009 and 0.01). In contrast, CDKN1B expression was not associated with miR-221 or miR-222 expression. Neither somatic mutations nor methylation of the studied region explained the alterations in miR-221 and miR-222 expression in most carcinomas.

Ovarian cancer

Ovarian carcinomas are a heterogeneous group of neoplasms and are traditionally subclassified based on type and degree of differentiation. Although current clinical management of ovarian carcinoma largely fails to take this heterogeneity into account, it is becoming evident that each major histological type has characteristic genetic defects that deregulate specific signaling pathways in the tumor cells. Moreover, within the most common histological types, the molecular pathogenesis of low-grade versus high-grade tumors appears to be largely distinct. Mouse models of ovarian carcinoma have been developed that recapitulate many of the morphological features, biological behavior, and gene-expression patterns of selected subtypes of ovarian cancer. Such models will likely prove useful for studying ovarian cancer biology and for preclinical testing of molecularly targeted therapeutics, which may ultimately lead to better clinical outcomes for women with ovarian cancer.

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.

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.

Significance of E2F-1 overexpression in epithelial ovarian cancer

E2F-1 is a downstream regulator of the Rb pathway and is a transcription factor that plays a key role in the control of cell cycle progression. Deregulation of E2F-1 expression and Rb pathway is involved in carcinogenesis. The aim of this study was to evaluate E2F-1 expression and Rb pathway alteration and to elucidate their correlation with clinical and pathologic parameters in epithelial ovarian cancer (EOC). We investigated overexpression of E2F-1 and alterations of p16(INK4a), cyclin D1, CDK4, and pRb using immunohistochemistry and tissue microarray methods in 72 EOC patients. Overexpression of E2F-1 was detected in 45.8% of samples. The overall abnormal expression frequencies of p16(INK4a), cyclin D1, CDK4, and pRb were 33.3%, 11.1%, 12.5%, and 38.9%, respectively. E2F-1 overexpression was not associated with alteration of the Rb pathway. E2F-1 overexpression was correlated with FIGO stage, histologic grade, and mitotic index; it was a valuable prognostic variable along with FIGO stage in the multivariated analysis. The results suggest that E2F-1 has a growth-promoting effect in EOC and that E2F-1 overexpression may provide a useful prognostic indicator for EOC.

Susceptibility of p27 kip1 knockout mice to urinary bladder carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine may not simply be due to enhanced proliferation

Deregulated proliferation is one of the fundamental characteristics of carcinogenesis. p27 is one of the most well characterized negative cell cycle regulator. In our previous study, expression of p27 protein was found to be dramatically suppressed on stimulation of cell proliferation by calculi in the rodent urinary bladder, withdrawal of the insult resulting in re-expression of p27 and regression of urothelial hyperplastic lesions. In the present study, to evaluate how loss of function impacts on urinary bladder carcinogenesis, N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), a bladder carcinogen was given to p27 knockout mice. Males and females with either null, hetero or wild-type p27 alleles were divided into 2 groups, one given drinking water containing 0.05% BBN for 10 weeks and the other receiving distilled water, then, killed at week 20. The experiment was repeated for confirmation of the outcome. In the second experiment, performed with a larger number of animals, the incidence of urinary bladder carcinomas was significantly higher in female p27-null mice than in their wild-type counterparts. p27 deficiency also resulted in their increase of relative weights of urinary bladders and section areas of carcinomas in BBN-treated mice. Interestingly, while BrdU labeling indices generally increased with progression of mucosal proliferative lesions, from normal epithelium, through hyperplasia to carcinoma, there was no significant variation with the p27 genotype, in tumors as well as normal urothelium. These findings suggest that p27 deficient mice have elevated susceptibility to BBN-induction of urinary bladder carcinogenesis through a mechanism which might be independent of acceleration of cell cycling.

Expression and prognostic significance of cyclin D3 in ovarian adenocarcinomas

Abnormal expression of cell cycle regulators may contribute to malignant transformation. However, the clinical significance of the expression of cyclin D3 in ovarian cancer remains undefined. We therefore conducted a retrospective investigation to address the role of this cell-cycle protein in this tumor. In our study, paraffin-embedded tissue from 109 nonbenign epithelial ovarian tumors, including 17 tumors of low malignant potential and 92 primary adenocarcinomas, was stained immunohistochemically for cyclin D3. Most of the cases had previously been stained for pRb, p21Cip1, p27Kip1, p53, and Ki-67 antigen. Expression of cyclin D3 was correlated with clinicopathologic features, the expression of other cell cycle regulators, and postoperative survival of patients. Cyclin D3 levels were significantly higher in tumors of low malignant potential than in adenocarcinomas (P = 0.0002). In the latter group, cyclin D3 expression decreased with increasing grade (P = 0.0004) and advancing stage (P = 0.0315). Cyclin D3 expression positively correlated with pRb, p21Cip1, and p27Kip1 levels (P = 0.0021; P = 0.0036; P < 0.0001, respectively) and negatively with p53 and Ki-67 (P = 0.0003; P < 0.0001). Absent cyclin D3 expression was an important indicator of poor survival in univariate analysis in the entire cohort (P > 0.00010) and in the platinum-treated patients (P = 0.001) and in multivariate analysis (P = 0.044). Our results demonstrate that absent or decreased cyclin D3 expression is adversely related to several clinicopathologic indicators of aggressiveness in ovarian adenocarcinomas and is combined with a better prognosis, suggesting that cyclin D3 may have a biological role distinct from that of other G1 cyclins which is possibly regulated through interaction with other cell cycle genes.

Cyclin E expression is correlated with tumor progression and predicts a poor prognosis in patients with ovarian carcinoma

BACKGROUND

Cyclins, cyclin dependent kinases (cdks), and their inhibitors act in combination to regulate progression through the cell cycle and often are dysregulated in carcinoma. The authors hypothesized that cyclin E plays an important role in ovarian carcinogenesis and that its overexpression may be an indicator of a poor prognosis.

METHODS

Immunohistochemical analysis of cyclin E expression was performed by image analysis in normal ovaries, cystadenomas, tumors of low malignant potential, and 405 primary ovarian carcinomas by using tissue microarray technology.

RESULTS

Overexpression of cyclin E was found in 63.2% of the samples and was associated with clear cell, poorly differentiated, and serous carcinoma (P < or = .001), high-grade tumors (P < or = .001), late-stage disease (P = .002), age older than 60 years at the time of diagnosis (P = .04), and suboptimal cytoreduction (P = .001). A high percentage of cyclin E-expressing cells was associated with a poor outcome in univariate and in multivariate analyses. In addition, cyclin E levels also reduced survival in the late-stage disease group and in patients who underwent suboptimal debulking.

CONCLUSIONS

Cyclin E was identified as an independent prognostic factor in patients with ovarian carcinoma. The accumulation of cyclin E protein may be a late event in tumorigenesis and may contribute to disease progression in these patients.

Interaction of nuclear receptors with the Wnt/beta-catenin/Tcf signaling axis: Wnt you like to know?

The cross-regulation of Wnt/beta-catenin/Tcf ligands, kinases, and transcription factors with members of the nuclear receptor (NR) family has emerged as a clinically and developmentally important area of endocrine cell biology. Interactions between these signaling pathways result in a diverse array of cellular effects including altered cellular adhesion, tissue morphogenesis, and oncogenesis. Analyses of NR interactions with canonical Wnt signaling reveal two broad themes: Wnt/beta-catenin modulation of NRs (theme I), and ligand-dependent NR inhibition of the Wnt/beta-catenin/Tcf cascade (theme II). Beta-catenin, a promiscuous Wnt signaling member, has been studied intensively in relation to the androgen receptor (AR). Beta-catenin acts as a coactivator of AR transcription and is also involved in co-trafficking, increasing cell proliferation, and prostate pathogenesis. T cell factor, a transcriptional mediator of beta-catenin and AR, engages in a dynamic reciprocity of nuclear beta-catenin, p300/CREB binding protein, and transcriptional initiation factor 2/GC receptor-interaction protein, thereby facilitating hormone-dependent coactivation and transrepression. Beta-catenin responds in an equally dynamic manner with other NRs, including the retinoic acid (RA) receptor (RAR), vitamin D receptor (VDR), glucocorticoid receptor (GR), progesterone receptor, thyroid receptor (TR), estrogen receptor (ER), and peroxisome proliferator-activated receptor (PPAR). The NR ligands, vitamin D(3), trans/cis RA, glucocorticoids, and thiazolidines, induce dramatic changes in the physiology of cells harboring high Wnt/beta-catenin/Tcf activity. Wnt signaling regulates, directly or indirectly, developmental processes such as ductal branching and adipogenesis, two processes dependent on NR function. Beta-catenin has been intensively studied in colorectal cancer; however, it is now evident that beta-catenin may be important in cancers of the breast, prostate, and thyroid. This review will focus on the cross-regulation of AR and Wnt/beta-catenin/Tcf but will also consider the dynamic manner in which RAR/RXR, GR, TR, VDR, ER, and PPAR modulate canonical Wnt signaling. Although many commonalities exist by which NRs interact with the Wnt/beta-catenin signaling pathway, striking cell line and tissue-specific differences require deciphering and application to endocrine pathology.

Cyclin-dependant kinase inhibitors CIP1 (p21) and KIP1 (p27) in ovarian cancer

PURPOSE

Deregulation of the cell cycle is one of the important prerequisites for cancer development. p21 and p27 are both universal inhibitors of cyclin-dependent kinases and can therefore influence cell cycle or tumor progression. The aim of this study was to determine the influence of p21 and p27 expression on survival and chemotherapy response.

METHODS

165 patients with ovarian cancer have been examined for p21 and p27 expression by immunohistochemistry on formalin-fixed, paraffin-embedded tissue using the monoclonal primary antibody WAF1 (Oncogene Science) and KIP1 (Transduction Laboratories).

RESULTS

High p21 expression (>50%) correlates only with early tumor stage (P=0.04). There was no correlation found between p21 and p27 expression. Patients with high p27 expression (>25%) had a longer DFS (disease free survival) in both univariate and multivariate analysis (P=0.05 and P=0.043) than patients with low p27 expression. A longer overall survival (OS) could only be proven for the group of high p27 expression in univariate analysis (P=0.03).

CONCLUSION

p27 is an independent prognostic factor for ovarian cancer for DFS though this was not true for OS.

Molecular pathogenesis of ovarian borderline tumors: new insights and old challenges

Ovarian borderline (low malignant potential) tumors are a puzzling group of neoplasms that do not fall neatly into benign or malignant categories. Their behavior is enigmatic, their pathogenesis unclear, and their clinical management controversial, especially for serous borderline tumors (SBT), the most common type of ovarian borderline tumor. Clarifying the nature of borderline tumors and their relationship to invasive carcinoma has puzzled investigators since the category was created over 30 years ago. Much of the confusion and controversy concerning these tumors is due to a lack of understanding of their pathogenesis and an absence of a model for the development of ovarian carcinoma. This review summarizes recent molecular studies of ovarian borderline tumors with special emphasis on the role of SBT in tumor progression and its relationship to ovarian serous carcinoma.

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.

Overexpression of cyclin D1 and c-Myc gene products in human primary epithelial ovarian cancer

Cyclin D1 and c-Myc are key participants in the cell-cycle pathway, in which aberrancies have been associated with malignant transformation. To date, data on the relationship of expression of these proteins and histologic subtype of epithelial ovarian cancer are still scarce and discordant. Immunohistochemical analysis was performed on 12 normal ovaries and 47 cases of serous, mucinous, endometrioid, and clear cell ovarian carcinomas. No abnormal expression of cyclin D1 or c-Myc was demonstrated in any of the 12 normal ovarian specimens. However, compared to normal ovarian tissues, overexpression of cyclin D1 and c-Myc was observed in 42.6% (20/47) and 65.9% (31/47) of tumors examined, respectively. There was no significant difference of overexpression of cyclin D1 or c-Myc gene products between these four histologic subtypes of ovarian adenocarcinomas. This study shows that cyclin D1 and c-Myc are frequently overexpressed in epithelial ovarian carcinomas, but they are not correlated with a particular histologic subtype. Although our preliminary results need to be validated in a larger number of tumors, the abnormal expression of cyclin D1 and c-Myc in epithelial ovarian cancer reaffirms the notion that they are crucial components in the pathway of tumorigenesis and deserve further study.

Discrimination between serous low malignant potential and invasive epithelial ovarian tumors using molecular profiling

Tumors of low malignant potential (LMP) represent 20% of epithelial ovarian cancers (EOCs) and are associated with a better prognosis than the invasive tumors (TOV). Defining the relationship between LMPs and TOVs remains an important goal towards understanding the molecular pathways that contribute to prognosis, as well as providing molecular markers, for these EOCs. To this end, DNA microarray analyses were performed either in a primary culture or a tumor tissue model system and selected candidate genes showing a distinctive expression profile between LMPs and TOVs were identified using a class prediction approach based on three statistical methods of analysis. Both model systems appear relevant as candidate genes identified by either model allowed the proper reclassification of samples as either LMPs or TOVs. Selected candidate genes (CAS, CCNE1, LGALS8, ITGbeta3, ATP1B1, FLIP, KRT7 and KRT19) were validated by real-time quantitative PCR analysis and show differential expression between LMPs and TOVs. Immunohistochemistry analyses showed that the two tumor classes were distinguishable by their expression of CAS, TNFR1A, FLIP, CKS1 and CCNE1. These results define signature patterns for gene expression of LMPs and TOVs and identify gene candidates that warrant further study to deepen our understanding of the biology of EOC.

Cyclin D1, p53, and p21Waf1/Cip1 expression is predictive of poor clinical outcome in serous epithelial ovarian cancer

PURPOSE

Dysregulation of cell cycle control, in particular G(1)-S-phase transition, is implicated in the pathogenesis of most human cancers, including epithelial ovarian cancer (EOC). However, the prognostic significance of aberrant cell cycle gene expression in EOC remains unclear.

EXPERIMENTAL DESIGN

The expression of selected genes from the pRb pathway that regulates G(1)-S-phase progression, including cyclin D1, p16(Ink4a), cyclin E, p27(Kip1), p21(Waf1/Cip1), and p53, was examined in a consecutive series of 134 serous EOC using immunohistochemistry and the results correlated to disease outcome.

RESULTS

Molecular markers predictive of reduced overall survival in univariate analysis were overexpression of cyclin D1 (P = 0.03) and p53 (P = 0.03) and reduced expression of p27(Kip1) (P = 0.05) and p21(Waf1/Cip1) (P = 0.02), with the latter three also being prognostic for a shorter progression-free interval. In addition, patients displaying overexpression of p53 with concurrent loss of p21(Waf1/Cip1) had a significantly shorter overall (P = 0.0008) and progression-free survival (P = 0.0001). On multivariate analysis, overexpression of cyclin D1 and combined loss of p21(Waf1/Cip1) in the presence of p53 overexpression were independent predictors of overall survival. Similarly, the combination of p21(Waf1/Cip1) loss and p53 overexpression was independently predictive of a shorter progression-free interval. Overexpression of p53 and cyclin E and reduced expression of p27(Kip1) and p21(Waf1/Cip1) were significantly associated with increasing tumor grade.

CONCLUSIONS

This study confirms that dysregulation of cell cycle genes is common in EOC, and that aberrant expression of critical cell cycle regulatory proteins can predict patient outcome in serous EOC.

Benign ovarian serous tumors: a re-evaluation and proposed reclassification of serous "cystadenomas" and "cystadenofibromas"

OBJECTIVE

Serous cystadenomas and cystadenofibromas of the ovaries are currently regarded as neoplasms and are considered the most common ovarian neoplasms. The purpose of this study is to determine what proportion of benign serous tumors contain an epithelial proliferation (the hallmark of a neoplastic process in nearly all other sites) that can be considered neoplastic as opposed to reactive in nature.

METHODS

An unselected series of 113 ovarian serous tumors (76 serous cystadenomas and 37 serous cystadenofibromas) were histologically evaluated. A 1-mm in diameter area of epithelial proliferation was considered potentially neoplastic.

RESULTS

Eight tumors (7%) displayed at least 1 mm of epithelial proliferation (1% of serous cystadenomas and 19% of serous cystadenofibromas).

CONCLUSION

The vast majority of benign serous tumors may not be bona fide epithelial neoplasms, but rather, may represent cystically dilated glandular inclusions (cystadenomas) and fibromas with epithelial inclusions (cystadenofibromas). A recently published study evaluating clonality in serous cystadenomas found that the vast majority are polyclonal and thus supports this hypothesis. These findings have important implications for the pathogenesis of ovarian cancer, for the distribution of ovarian neoplasms, and for the interpretation of molecular biological studies of ovarian tumors.

Subcellular Localization of p27kip1 Expression Predicts Poor Prognosis in Human Ovarian Cancer

Purpose: The cyclin-dependent kinase inhibitor p27kip1 regulates cellular progression from G1 to S phase. Several studies have shown that loss of p27kip1 protein expression is associated with disease progression in various malignancies. The purpose of this study was to evaluate the subcellular localization of this cyclin-dependent kinase inhibitor in a large cohort of primary ovarian carcinomas and compare the results with clinicopathologic variables and overall survival.

Experimental Design: Subcellular localization of p27kip1 was first assessed by Western blotting in nuclear and cytoplasmic extract from 13 cases of ovarian carcinoma. Subcellular localization of the p27kip1 protein was evaluated using tissue microarrays containing 421 cases of ovarian carcinoma.

Results: The presence of p27kip1 in the cytoplasm regardless of the nuclear stain correlated strongly with late-stage disease (P &lt; 0.03), extent of cytoreduction (P = 0.03), and shorter disease-specific survival (P &lt; 0.0001).

Conclusion: Cytoplasmic localization of p27kip1 predicts poorer prognosis in ovarian carcinoma, particularly in late-stage disease.

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.

CAS (cellular apoptosis susceptibility) gene expression in ovarian carcinoma: Correlation with 20q13.2 copy number and cyclin D1, p53, and Rb protein expression

We immunohistochemically analyzed cellular apoptosis susceptibility (CAS) protein expression and compared it with 20q13.2 copy number and the expression of cell cycle-associated proteins retinoblastoma (Rb), cyclin D1, and p53 and prognosis on paraffin-embedded tissue from 69 ovarian carcinomas (OCs). CAS protein reactivity was present in 100%, Rb in 54%, cyclin D1 in 47%, and p53 in 49%. Significant reciprocal correlation was observed between high levels of CAS and histologic type, FIGO (International Federation of Obstetrics and Gynecology) stage III and grade 3, residual tumor (>2 cm), 20q13.2 (ZNF217 gene) amplification (>4 copies in >20% cells), and high expression of cyclin D1 (all P < .05). No association was found between cyclin D1, p53, or Rb levels with clinicopathologic factors. In univariate analysis, residual tumor, FIGO stage and grade, ZNF217 amplification, and CAS levels predicted outcome (all P < .05). In multivariate analysis, stage, grade, amount of residual tumor, and ZNF217 amplification showed independent prognostic value (all P < .05). In OC, alteration of CAS and ZNF217 genes, both located at 20q13, is frequent and relevant prognostically. Cyclin D1, Rb, and p53 seem to have a secondary role.

Role of beta-catenin/T-cell factor-regulated genes in ovarian endometrioid adenocarcinomas

In various cancers, inactivating mutations in the adenomatous polyposis coli or Axin tumor suppressor proteins or activating mutations in beta-catenin's amino-terminal domain elevate beta-catenin levels, resulting in marked effects on T-cell factor (TCF)-regulated transcription. Several candidate beta-catenin/TCF-regulated genes in cancer have been proposed. Expression of a few of these genes has been studied in primary human cancers, but most studies have focused on colon cancers and not on other cancer types that harbor mutational defects in adenomatous polyposis coli, AXIN, or beta-catenin. Mutations leading to beta-catenin deregulation are found in nearly half of ovarian endometrioid adenocarcinomas (OEAs). We report here on the expression of 6 candidate beta-catenin/TCF-regulated genes in a panel of 44 primary OEAs, more than a third of which carry demonstrable defects in beta-catenin regulation. Using quantitative assays of gene expression, we found significantly elevated expression of the MMP-7, CCND1 (Cyclin D1), CX43 (Connexin 43), PPAR-delta, and ITF2 genes in OEAs with deregulated beta-catenin. This correlation was not observed for c-myc, another putative beta-catenin/TCF-regulated gene. Immunohistochemical studies confirmed that overexpression of cyclin D1 and MMP-7 was highly associated with nuclear accumulation of beta-catenin and mutational defects of the Wnt/beta-catenin/TCF-signaling pathway. Our findings indicate cyclin D1, MMP-7, connexin 43, PPAR-delta, and ITF-2, likely play important roles in the pathogenesis of those OEAs that manifest defects in beta-catenin regulation.

Expression and subcellular localization of the cyclin-dependent kinase inhibitor p27(Kip1) in epithelial ovarian cancer

OBJECTIVE

To determine if p27(Kip1) expression was altered in epithelial ovarian cancers as compared to normal ovarian surface epithelial (NOSE) cells and to determine if subcellular localization of p27(Kip1) was an important feature.

METHODS

Thirteen tumor samples (1 Stage IC [early] and 12 Stage III/IV [advanced]) from patients with epithelial ovarian cancer and five NOSE samples were evaluated. Samples were surgically dissected to obtain an enriched population (90%) of cancer cells. The level of p27(Kip1) protein expression was determined by Western blot analysis. Actin was used as a loading control, and results were quantified by scanning densitometry using the ratio of the p27(Kip1) signal to the actin signal for comparison. To evaluate the subcellular localization of p27(Kip1), immunocytochemical staining was performed. Clinical pathological parameters were correlated to nuclear p27(Kip1) staining to establish if any association existed.

RESULTS

When comparing the expression of p27(Kip1) between NOSE and ovarian cancer samples, only 2 of 13 ovarian cancer samples had altered p27(Kip1) expression. No correlation was found between the expression level of p27(Kip1) on Western blot and clinical pathological correlates. While no correlation between expression level of p27(Kip1) and subcellular localization was found, decreased nuclear staining (1+) was associated with shorter survivals using the log-rank test (P < 0.001). More importantly, in all tumor samples examined under the microscope, no nuclear p27(Kip1) staining was noted in cells that were undergoing mitosis.

CONCLUSIONS

p27(Kip1) protein degradation may not be modified in ovarian cancer cells undergoing mitosis. Altered expression of p27(Kip1) is not an overwhelming feature in certain epithelial ovarian cancers. Decreased nuclear staining of p27(Kip1) is associated with poor survival in some epithelial ovarian cancers.

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.

Implication of malignancy and prognosis of p27(kip1), Cyclin E, and Cdk2 expression in epithelial ovarian tumors

OBJECTIVE

The aim of this study was to further evaluate whether the expression of p27(kip1), cyclin E, and cdk2 is related to the malignancy of ovarian tumors and whether their expressions, alone or in combination, are associated with prognosis in epithelial ovarian carcinoma.

METHODS

Immunohistochemical analysis using anti-p27(kip1), anti-cyclinE, and anti-cdk2 antibodies was carried out for 103 cases consisting of benign, borderline, and malignant ovarian tumors, and Western blot analysis and cdk2 activity assay were performed in 26 fresh ovarian tumor samples.

RESULTS

p27(kip1) expression was reduced in ovarian carcinomas in contrast to benign and borderline tumors. The expression of cyclin E and cdk2 gradually increased from benign to borderline to malignant tumors. Kaplan-Meier survival analysis showed that patients with p27(kip1) expression had a high overall survival rate. Patients with cyclin E overexpression had a low overall survival rate. When the combination of these proteins was analyzed, patients with the p27(kip1) (-)/cyclin E (++)/cdk2 (++) phenotype were significantly associated with the poorest overall survival. In multivariate Cox regression analysis, the combined phenotype of p27(kip1) (-)/cyclin E (++)/cdk2 (++) was independently related to poor prognosis.

CONCLUSIONS

Our results suggest that loss of p27(kip1) expression and overexpression of cyclin E or cdk2 were significantly associated with malignancy in ovarian tumors. p27(kip1) and cyclin E proteins may be valuable prognostic factors for epithelial ovarian carcinoma patients. Furthermore, the combined evaluation of p27(kip1)/cyclin E/cdk2 may provide the most important prognostic implication.

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.

Anomalous overexpression of p27(Kip1) in sporadic pancreatic endocrine tumors

BACKGROUND

Little is known about the cellular defects and molecular mechanisms leading to pancreatic endocrine tumors (PETs). p27(Kip1) is a universal cyclin-dependent kinase inhibitor (CDKI), which acts as a tumor suppressor and a negative regulator of cell cycle. From previous reports, quiescent cells show high levels of p27(Kip1) expression while neoplastic and proliferating cells show no detectable p27(Kip1) expression. We hypothesize that in malignant sporadic PETs, p27(Kip1) expression would be decreased compared with benign PETs and normal pancreatic tissue.

METHODS

Western analysis was performed on 28 PETs (7 malignant, 21 benign), 2 nonendocrine cell lines, and 5 endocrine cell lines. Signal intensities were quantitated using densitometry and standardized to normal pancreas.

RESULTS

Unexpectedly, increased p27(Kip1) expression as compared with control was seen in both benign and malignant tumors, as well as in all four pancreatic islet tumor cell lines, but not fibroblast or pituitary cell lines, evaluated. There was no difference in p27(Kip1) level between benign and malignant tumors.

CONCLUSION

This represents the first report of anomalous p27(Kip1) overexpression in sporadic PETs, and is part of a growing literature describing the paradoxical overexpression of p27(Kip1) in human tumors that includes other endocrine tumors. These studies suggest a unique molecular pathway leading to endocrine tumorigenesis.

Inverse expression of Cdk4 and p16 in epithelial ovarian tumors

OBJECTIVES

The aim of this study was to elucidate the expression and the correlation of two cell cycle regulators, cdk4 and its inhibitor p16, in a series of benign, borderline, and malignant ovarian tumors and to evaluate whether their alterations correlate with clinicopathologial parameters and patients' prognosis in epithelial ovarian carcinomas.

METHODS

Immunohistochemical analysis using anti-cdk4 and anti-p16 antibodies was carried out for 103 paraffin sections of ovarian tumors, and Western blot analysis and cdk4 activity assay were performed in 26 fresh ovarian tumor samples.

RESULTS

The results of immunohistochemistry showed that 60.61 and 69.70% of benign, 69.57 and 56.52% of borderline, and 74.47 and 40. 43% of malignant tumors expressed cdk4 and p16, respectively, demonstrating increased cdk4 and decreased p16 expression in ovarian carcinomas. A significant inverse relationship between cdk4 and p16 expression was found. The loss of p16 expression was more correlated with G(2) and G(3) tumors in contrast with G(1) tumors. No significant correlation was observed between cdk4 expression and clinicopathological parameters. Neither cdk4 nor p16 expression has significant effects on overall survival by the Kaplan-Meier method. When the combined phenotypes of the two proteins were analyzed, patients with cdk4-positive/p16-negative expression had a reduced overall survival than other phenotypes of cdk4/p16.

CONCLUSIONS

These data suggest that inverse expression of cdk4 and p16 may be involved in the development and progression of epithelial ovarian carcinomas. The combined phenotypes of cdk4 and p16 proteins could provide a useful prognostic indicator for patients with epithelial ovarian carcinoma.

p27(kip1) protein expression correlates with survival in myxoid and round-cell liposarcoma

PURPOSE

The p27(kip1) protein (p27) is a cyclin-dependent kinase inhibitor that has been shown to be an independent prognostic factor in a variety of human neoplasms. Low expression of p27 tends to occur in more aggressive neoplasms. The role of p27 as an independent prognostic factor in the spectrum of myxoid and round-cell liposarcomas has not been examined.

MATERIALS AND METHODS

Forty-seven cases of myxoid and round-cell liposarcomas were examined. Clinicopathologic features and immunohistochemical expression of p27 and Ki-67 antigen were studied in all cases. Survival analysis was performed using the log-rank test and the Cox multivariate regression model.

RESULTS

The male:female ratio was 1. 4:1, and the mean age at diagnosis was 45 years. The tumors were located in the lower extremities (94%) and retroperitoneum (6%). The median tumor size was 13.5 cm. The median follow-up was 6.3 years, and the overall 5- and 10-year survival rates were 76% and 67%, respectively. Low expression of p27 was identified in 34 cases (72%) and correlated with decreased metastasis-free (P =.026) and overall survival (P =.008). In a multivariate analysis, only round-cell differentiation and low expression of p27 independently predicted decreased metastasis-free and overall survival.

CONCLUSION

p27 expression predicts the clinical behavior of myxoid and round-cell liposarcomas, even in neoplasms with few or no round-cell differentiation.

p27 and cyclin D1 abnormalities in uterine papillary serous carcinoma

OBJECTIVE

The expression status of p27 and cyclin D1 was examined in 21 uterine papillary serous carcinoma (UPSC) specimens to determine the role of these genes in the development of this disease. The status of p53, p16, Rb, and K-ras was also determined in these tissues so that a marker profile for UPSC could be compared with the published marker profile for other forms of endometrial and ovarian cancer.

METHODS

Immunohistochemistry was performed on 21 UPSC tissue sections to determine the expression status of p27, cyclin D1, p53, p16, and Rb. K-ras mutations were identified by restriction fragment length polymorphism analysis of DNA isolated from the UPSC sections.

RESULTS

All specimens displayed at least one molecular abnormality. A high incidence of p27 alterations were observed, with reduced p27 expression measured in 16 of 21 (76%) tumors, followed by p53 alterations observed in 13 of 21 (62%) tumors. The p27 abnormalities occur at an early stage of the disease, with 63% (5/8) of Stage I cases displaying reduced p27 expression. Cyclin D1 overexpression was observed in 4 of 21 (19%) specimens, whereas p16, Rb, and K-ras abnormalities were each observed in 2 of 21 specimens (10%). Both K-ras mutations were at codon 12. The p16 and Rb abnormalities coexisted in the same specimens.

CONCLUSION

UPSC tumors display a high incidence of p27 abnormalities, suggesting that p27 abnormalities play an important role in the development of this disease. Our results also indicate that cyclin D1 overexpression is involved in the development of a small number of UPSC cases. A comparison of our results with reports by other authors suggests that UPSC shares molecular marker alterations with both ovarian cancer and endometrioid adenocarcinoma.

Ovarian serous borderline tumors: a critical review of the literature with emphasis on prognostic indicators

BACKGROUND

The behavior of ovarian serous borderline tumors (SBTs) and significance of various prognostic factors are unclear and difficult to evaluate because of inconsistencies and confusion in the literature. Recent studies have suggested that the morphological features of the primary tumor (presence or absence of micropapillary features) and the peritoneal "implants" (presence or absence of invasive features) can reliably subclassify SBTs into benign and malignant types. The aim of the current review was to test two hypotheses. First, that the alleged malignant behavior of SBTs is poorly documented, and second, that the morphological features of the primary ovarian tumors and the associated peritoneal implants are sufficient to separate SBTs into benign and malignant types, thereby obviating the need for the category.

METHODS

245 studies reporting approximately 18,000 patients with borderline ovarian tumors were reviewed. After excluding series that lacked clinical follow-up or were not analyzable for other reasons, there remained 97 reports that included 4,129 patients. In addition to recurrences and survival, we evaluated the type of peritoneal implants, microinvasion, lymph node involvement, late recurrences, and progression to carcinoma, as these features have served as the underpinning of the concept of "borderline malignancy" or "low malignant potential."

RESULTS

Among 4,129 patients with SBTs reviewed, the recurrence rate after a mean follow-up of 6.7 years was 0.27% per year for stage I tumors, the disease-free survival was 98.2%, and the overall disease-specific survival rate was 99.5%. For patients with advanced-stage tumors, the recurrence rate was 2.4% per year. However, the majority (69%) of reported recurrences were not pathologically documented, and only 26 cases (8.4% of all recurrences) were documented to have recurred from an adequately sampled ovarian tumor. The most reliable prognostic indicator for advanced stage tumors was the type of peritoneal implant. After 7.4 years of follow-up, the survival of patients with noninvasive peritoneal inplants was 95.3%, as compared with 66% for invasive implants (P < .0001). Microinvasion in the primary ovarian tumor was associated with a 100% survival rate at 6.7 years, and lymph node involvement was associated with a 98% survival rate at 6.5 years. The few reported cases of stage IV disease, progression to invasive carcinoma, and very late (>20 years) recurrences were poorly documented. The survival for all stages among approximately 373 patients in 6 prospective randomized trials followed for a mean of 6.7 years was 100%.

CONCLUSION

Surgical pathological stage and subclassification of extraovarian disease into invasive and noninvasive implants are the most important prognostic indicators for SBTs. Survival for stage I tumors is virtually 100%. Survival for advanced stage tumors with noninvasive implants is 95.3%, whereas survival for tumors with invasive implants is 66%. Invasive implants behave as carcinomas and are most likely metastatic. The precise nature of so-called noninvasive implants is not clear, but they behave in a benign fashion. The presence of a micropapillary architecture in the primary ovarian tumor is a strong predictor of invasive implants. These data support the recommendation that ovarian tumors with a micropapillary architecture be designated "micropapillary serous carcinomas," and those lacking these features, "atypical proliferative serous tumors."

Ovarian cancer cells that coexpress endogenous Rb and p16 are insensitive to overexpression of functional p16 protein

Defects of the 'Rb/cyclin D1/p16 pathway' have been shown to play a critical role in the development of virtually all human malignancies assessed. To determine the contribution of G1 phase cell cycle defects to ovarian tumorigenesis, we have examined a panel of normal and tumor ovarian tissues and ovarian cancer cell lines for the expression of Rb, p16 and cyclin D1 proteins. Unlike most types of human cancer whose development involves the loss of either Rb or p16 expression, we observed the coexpression of Rb, p16 and cyclin D1 in 82% of ovarian cancer tissues and cell lines. Furthermore, the growth and cell cycle distribution profiles of three ovarian cancer cell lines (ES-2, PA-1 and NIH OVCAR-3) that coexpressed Rb and p16, were found to be unaffected by adenoviral-mediated overexpression of functional p16 protein, indicating the existence of a defect(s) downstream from p16 in these cells. By contrast overexpression of ectopic p16 in the one ovarian cancer cell line (SK-OV-3) that expressed Rb but lacked p16 protein, resulted in a G1 growth arrest. These data suggest that defects of the 'Rb/cyclin D1/p16 pathway', other than the loss of Rb or p16, may play a major role in the development of ovarian cancer.