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

c-MYC and Epithelial Ovarian Cancer

Ovarian cancer is the deadliest of gynecological malignancies with approximately 49% of women surviving 5 years after initial diagnosis. The standard of care for ovarian cancer consists of cytoreductive surgery followed by platinum-based combination chemotherapy. Unfortunately, despite initial response, platinum resistance remains a major clinical challenge. Therefore, the identification of effective biomarkers and therapeutic targets is crucial to guide therapy regimen, maximize clinical benefit, and improve patient outcome. Given the pivotal role of c-MYC deregulation in most tumor types, including ovarian cancer, assessment of c-MYC biological and clinical relevance is essential. Here, we briefly describe the frequency of c-MYC deregulation in ovarian cancer and the consequences of its targeting.

Biologic Mechanisms Linked to Prognosis in Ovarian Cancer that May Be Affected by Aging

The increase of both life expectancy of the Western industrialized population and cancer incidence with aging is expected to result in a rapid expansion of the elderly cancer population, including patients with epithelial ovarian cancer (EOC). Although the survival of patients with EOC has generally improved over the past three decades, this progress has yet to provide benefits for elderly patients. Compared with young age, advanced age has been reported as an adverse prognostic factor influencing EOC. However, contradicting results have been obtained, and the mechanisms underlying this observation are poorly defined. Few papers have been published on the underlying biological mechanisms that might explain this prognosis trend. We provide an extensive review of mechanisms that have been linked to EOC prognosis and/or aging in the published literature and might underlie this relationship in humans.

Endometriosis-associated ovarian cancer: What have we learned so far?

Endometriosis is defined as the presence of ectopic endometrial tissue outside of the uterine cavity, most commonly in the ovaries and peritoneum. It is a complex disease that is influenced by multiple factors. It is also a common gynecological disorder and affects approximately 10-15% of all women of reproductive age. Recent molecular and pathological studies indicate that endometriosis may serve as a precursor of ovarian cancer (endometriosis-associated ovarian cancer, EAOC), particularly endometrioid and clear cell ovarian cancers. Although histological and epidemiological studies have demonstrated that endometriosis has a malignant potential, the molecular mechanism that underlies the malignant transformation of endometriosis is still controversial, and the precise mechanism of carcinogenesis must be fully elucidated. Currently, the development and improvement of a new sequencing technology, next-generation sequencing (NGS), has been increasingly relevant in cancer genomics research. Recently, NGS has also been utilized in clinical oncology to advance the personalized treatment of cancer. In addition, the sensitivity, speed, and cost make NGS a highly attractive platform compared to other sequencing modalities. For this reason, NGS may lead to the identification of driver mutations and underlying pathways associated with EAOC. Here, we present an overview of the molecular pathways that have led to the current opinions on the relationship between endometriosis and ovarian cancer.

Origins based clinical and molecular complexities of epithelial ovarian cancer

Ovarian cancer is the most lethal of all common gynaecological malignancies in women worldwide. Ovarian cancer comprises of >15 distinct tumor types and subtypes characterized by histopathological features, environmental and genetic risk factors, precursor lesions and molecular events during oncogenesis. Recent studies on gene signature profiling of different subtypes of ovarian cancer have revealed significant genetic heterogeneity between and within each ovarian cancer histological subtype. Thus, an immense interest have shown towards a more personalized medicine for understanding the clinical and molecular complexities of four major types of epithelial ovarian cancer (serous, endometrioid, clear cell, and mucinous). As such, further in depth studies are needed for identification of molecular signalling network complexities associated with effective prognostication and targeted therapies to prevent or treat metastasis. Therefore, understanding the metastatic potential of primary ovarian cancer and therapeutic interventions against lethal ovarian cancer for the development of personalized therapies is very much indispensable. Consequently, in this review we have updated the key dysregulated genes of four major subtypes of epithelial carcinomas. We have also highlighted the recent advances and current challenges in unravelling the complexities of the origin of tumor as well as genetic heterogeneity of ovarian cancer.

Immunohistochemical Expression of p53, MDM2, and p21Wafi Oncoproteins in Endometriomas But Not Adenomyosis

OBJECTIVE

p53, MDM2, and p21Waf1 are oncoproteins that regulate the cell cycle. The purpose of this study was to examine the distribution of p53, MDM2, and p21Waf1 oncoprotein expression in endometriomas and in adenomyosis.

METHODS

Tissue samples from 25 women with pathologically confirmed endometriomas and 31 women with pathologically confirmed adenomyosis were analyzed. Expression of p53, MDM2, and p21Waf1 oncoproteins was assessed by immunohistochemical nuclear staining.

RESULTS

p53, MDM2, and p21Waf1 expression were detected in 20%, 60%, and 80% of endometrioma tissue samples, respectively. All endometrioma tissue samples expressing p53 also tested positive for both MDM2 and p21Waf1. MDM2 expression was significantly higher in the proliferative than in the secretory phase of the cycle. In contrast, all 31 adenomyosis tissue samples were negative for p53, MDM2, and p21Waf1 expression.

CONCLUSION

The expression of p53, MDM2, and p21Waf1 suggests a role for these oncoproteins in the regulation of endometrioma cell growth, but not in adenomyosis.

Histone deacetylases as new therapy targets for platinum-resistant epithelial ovarian cancer

Introduction

In developed countries, ovarian cancer is the fourth most common cancer in women. Due to the non-specific symptomatology associated with the disease many patients with ovarian cancer are diagnosed late, which leads to significantly poorer prognosis. Apart from surgery and radiotherapy, a substantial number of ovarian cancer patients will undergo chemotherapy and platinum based agents are the mainstream first-line therapy for this disease. Despite the initial efficacy of these therapies, many women relapse; therefore, strategies for second-line therapies are required. Regulation of DNA transcription is crucial for tumour progression, metastasis and chemoresistance which offers potential for novel drug targets.

Methods

We have reviewed the existing literature on the role of histone deacetylases, nuclear enzymes regulating gene transcription.

Results and conclusion

Analysis of available data suggests that a signifant proportion of drug resistance stems from abberant gene expression, therefore HDAC inhibitors are amongst the most promising therapeutic targets for cancer treatment. Together with genetic testing, they may have a potential to serve as base for patient-adapted therapies.

Expression of p53, Ki67, epidermal growth factor receptor, transforming growth-factorα, and p21 in primary and secondary hyperparathyroidism

BACKGROUND

Secondary hyperparathyroidism (SH) is major problem in chronic renal failure. There are studies to examine proliferation and apoptosis associated biomarkers expressions in parathyroid lesions to reveal specific features. In this study, we evaluated the expression of some growth factors and their receptors in parathyroid gland of patients with SH or primary hyperparathyroidism (PH).

MATERIALS AND METHODS

A total of 49 patients had been operated for PH and 26 for SH. Parathyroid tissue samples were evaluated histopathologically and immunohistochemically using antibodies to human p53, Kİ-67, anti-human p21, antitransforming growth factor (TGF) α, CPP32 (caspase 3), and epidermal growth factor receptor (EGFR).

RESULTS

Adenoma was higher in PH compared with SH as 48/49 and 3/26, respectively (P = 0.000). Parathyroid hyperplasia was found in 23/26 patients with SH and 1/49 patient with PH. In parathyroid tissue there were no difference between PH and SH for p53, Ki-67, caspase, EGFR expressions; while there were significantly difference for TGFα (P = 0.047) and borderline significant difference for p21 (P = 0.06) expressions.

CONCLUSION

Adenoma was priority present in PH patients, hyperplasia was present in SH. There were no differences between primary and SH or adenoma and hyperplasia for expressions of cycline-dependent kinase inhibitor p21, p53, EGFR, Ki67, caspase; while TGFα expression was found to be different.

Discovery of co-occurring driver pathways in cancer

Background

It has been widely realized that pathways rather than individual genes govern the course of carcinogenesis. Therefore, discovering driver pathways is becoming an important step to understand the molecular mechanisms underlying cancer and design efficient treatments for cancer patients. Previous studies have focused mainly on observation of the alterations in cancer genomes at the individual gene or single pathway level. However, a great deal of evidence has indicated that multiple pathways often function cooperatively in carcinogenesis and other key biological processes.

Results

In this study, an exact mathematical programming method was proposed to de novo identify co-occurring mutated driver pathways (CoMDP) in carcinogenesis without any prior information beyond mutation profiles. Two possible properties of mutations that occurred in cooperative pathways were exploited to achieve this: (1) each individual pathway has high coverage and high exclusivity; and (2) the mutations between the pair of pathways showed statistically significant co-occurrence. The efficiency of CoMDP was validated first by testing on simulated data and comparing it with a previous method. Then CoMDP was applied to several real biological data including glioblastoma, lung adenocarcinoma, and ovarian carcinoma datasets. The discovered co-occurring driver pathways were here found to be involved in several key biological processes, such as cell survival and protein synthesis. Moreover, CoMDP was modified to (1) identify an extra pathway co-occurring with a known pathway and (2) detect multiple significant co-occurring driver pathways for carcinogenesis.

Conclusions

The present method can be used to identify gene sets with more biological relevance than the ones currently used for the discovery of single driver pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2105-15-271) contains supplementary material, which is available to authorized users.

Pathway modulations and epigenetic alterations in ovarian tumorbiogenesis

Cellular pathways are numerous and are highly integrated in function in the control of cellular systems. They collectively regulate cell division, proliferation, survival and apoptosis of cells and mutagenesis of key genes that control these pathways can initiate neoplastic transformations. Understanding these pathways is crucial to future therapeutic and preventive strategies of the disease. Ovarian cancers are of three major types; epithelial, germ-cell, and stromal. However, ovarian cancers of epithelial origin, arising from the mesothelium, are the predominant form. Of the subtypes of ovarian cancer, the high-grade serous tumors are fatal, with low survival rate due to late detection and poor response to treatments. Close examination of preserved ovarian tissues and in vitro studies have provided insights into the mechanistic changes occurring in cells mediated by a few key genes. This review will focus on pathways and key genes of the pathways that are mutated or have aberrant functions in the pathology of ovarian cancer. Non-genetic mechanisms that are gaining prominence in the pathology of ovarian cancer, miRNAs and epigenetics, will also be discussed in the review.

Immunoexpression and prognostic role of p53 in different subtypes of epithelial ovarian carcinoma

We sought to investigate the significance of p53 expression for epithelial ovarian carcinoma. In this study, we used immunohistochemical method to investigate the expression patterns of p53 in different subtypes of epithelial ovarian carcinoma. We found that the expressions of p53 protein in epithelial ovarian cancer (pituita, serosity and intima) were 88.9%, 75% and 100%, respectively, while the recurrence rates among three cancer subtypes were significantly different (33.3%, 12.5% and 0%, respectively; P < 0.05). Compared with patients without lymph node metastasis, the expression of p53 in patients with lymph node metastasis was significantly strong (68.75% and 100%, respectively; P < 0.05). However, the recurrence rate in the patients with lymph node metastasis (40%) was higher than that without lymph node metastasis (6.25%, P < 0.05). The expressions of p53 protein in ovarian cancer between I-II (25%) stage and II-IV stage (100%) were significantly different (P < 0.05), and the recurrence rates between the two groups were significantly different (0% and 31.25%, respectively, P < 0.05). Therefore, p53 protein has an intimate relationship with the malignant degree and the prognosis of ovarian cancer.

Implementing an online tool for genome-wide validation of survival-associated biomarkers in ovarian-cancer using microarray data from 1287 patients

The validation of prognostic biomarkers in large independent patient cohorts is a major bottleneck in ovarian cancer research. We implemented an online tool to assess the prognostic value of the expression levels of all microarray-quantified genes in ovarian cancer patients. First, a database was set up using gene expression data and survival information of 1287 ovarian cancer patients downloaded from Gene Expression Omnibus and The Cancer Genome Atlas (Affymetrix HG-U133A, HG-U133A 2.0, and HG-U133 Plus 2.0 microarrays). After quality control and normalization, only probes present on all three Affymetrix platforms were retained (n=22,277). To analyze the prognostic value of the selected gene, we divided the patients into two groups according to various quantile expressions of the gene. These groups were then compared using progression-free survival (n=1090) or overall survival (n=1287). A Kaplan-Meier survival plot was generated and significance was computed. The tool can be accessed online at www.kmplot.com/ovar. We used this integrative data analysis tool to validate the prognostic power of 37 biomarkers identified in the literature. Of these, CA125 (MUC16; P=3.7×10(-5), hazard ratio (HR)=1.4), CDKN1B (P=5.4×10(-5), HR=1.4), KLK6 (P=0.002, HR=0.79), IFNG (P=0.004, HR=0.81), P16 (P=0.02, HR=0.66), and BIRC5 (P=0.00017, HR=0.75) were associated with survival. The combination of several probe sets can further increase prediction efficiency. In summary, we developed a global online biomarker validation platform that mines all available microarray data to assess the prognostic power of 22,277 genes in 1287 ovarian cancer patients. We specifically used this tool to evaluate the effect of 37 previously published biomarkers on ovarian cancer prognosis.

miRNA profiling along tumour progression in ovarian carcinoma

MicroRNAs (miRNAs) are small non-coding RNAs that exert a regulatory effect post-transcriptionally by binding target mRNAs and inhibiting gene translation. miRNA expression is deregulated in cancer. The aim of this study was to characterize the differences in miRNA expression pattern and the miRNA-regulating machinery between ovarian carcinoma (OC) cells in primary tumours versus effusions. Using miRNA array platforms, we analysed a set of 21 tumours (13 effusions, 8 primary carcinomas) and identified three sets of miRNAs, one that is highly expressed in both primary carcinomas and effusions, one overexpressed in primary carcinomas and one overexpressed in effusions. Levels of selected miRNAs were analysed using quantitative PCR in an independent set of 45 additional tumours (30 effusions, 15 primary carcinomas). Reduced miR-145 and miR-214 and elevated let-7f, miR-182, miR-210, miR-200c, miR-222 and miR-23a levels were found in effusions in both sets. In silico target prediction programs identified potential target genes for some of the differentially expressed miRNAs. Expression of zinc finger E-box binding homeobox (ZEB)1 and c-Myc, targets of miR-200c, as well as of p21 protein (Cdc42/Rac)-activated kinase (PAK)1 and phosphatase and tensin homologue deleted on chromosome 10 (PTEN), predicted targets of miR-222, were analysed. Inverse correlations between expression levels of the indicated miRNAs and of the predicted target genes were found. In addition, higher expression of the miRNA-processing molecules Ago1, Ago2 and Dicer was observed in effusions compared to primary carcinomas. In conclusion, our data are the first to document different miRNA expression and regulation profiles in primary and metastatic OC, suggesting a role for these molecules in tumour progression.

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.

Xanthohumol decreases Notch1 expression and cell growth by cell cycle arrest and induction of apoptosis in epithelial ovarian cancer cell lines

OBJECTIVE

Notch1 signaling is active in ovarian cancer and is a promising pathway for new therapies in ovarian cancer. We have previously detected high Notch1 expression in ovarian tumors. Xanthohumol has been shown to inhibit cancer cell growth and invasion, including Kaposi's sarcoma, which also highly expresses Notch1. We hypothesized that the Notch1 signaling pathway is targeted by xanthohumol leading to decreased ovarian cancer cell growth.

METHODS

SKOV3 and OVCAR3 cells were utilized. MTT growth assays were conducted following treatment with xanthohumol. Quantitative RT-PCR and Western blot analyses were conducted to assess Notch1 down-regulation. Luciferase reporter assays were performed to assess functional down-regulation of Notch1. Cell cycle analysis was performed by flow cytometry.

RESULTS

Significant growth inhibition and down-regulation of Notch1 transcription and protein expression were found following xanthohumol treatment. In addition, xanthohumol increased Hes6 transcription and decreased Hes1 transcription, known downstream targets of Notch 1. These observations were associated with cell cycle inhibition as demonstrated by an increase in p21 expression and S and G2/M cell cycle arrest confirmed by an increase in phosphorylated cdc2. Furthermore, an increase in the apoptotic markers, cleaved caspase-3 and cleaved PARP were observed.

CONCLUSION

Xanthohumol was a potent inhibitor of ovarian cancer cell growth, and our results suggest that xanthohumol may be influencing the Notch1 pathway. These findings suggest that xanthohumol could be useful as a therapeutic agent in ovarian cancer.

Predictive and prognostic protein biomarkers in epithelial ovarian cancer: recommendation for future studies

Epithelial ovarian cancer is the most lethal gynecological malignancy. Due to its lack of symptoms, this disease is diagnosed at an advanced stage when the cancer has already spread to secondary sites. While initial rates of response to first treatment is >80%, the overall survival rate of patients is extremely low, mainly due to development of drug resistance. To date, there are no reliable clinical factors that can properly stratify patients for suitable chemotherapy strategies. Clinical parameters such as disease stage, tumor grade and residual disease, although helpful in the management of patients after their initial surgery to establish the first line of treatment, are not efficient enough. Accordingly, reliable markers that are independent and complementary to clinical parameters are needed for a better management of these patients. For several years, efforts to identify prognostic factors have focused on molecular markers, with a large number having been investigated. This review aims to present a summary of the recent advances in the identification of molecular biomarkers in ovarian cancer patient tissues, as well as an overview of the need and importance of molecular markers for personalized medicine in ovarian cancer.

Changes in expression, and/or mutations in TGF-beta receptors (TGF-beta RI and TGF-beta RII) and Smad 4 in human ovarian tumors

PURPOSE

Loss of sensitivity to transforming growth factor beta (TGF-beta) signaling typically occurs in human ovarian cancer cells, but there is paucity of information regarding this in human ovarian tumors. Thus the association of inactivating mutations and/or variations in expression levels of TGF-beta signaling components with human ovarian tumors was evaluated.

METHODS

Forty human ovarian tissue samples were analyzed for mutations and/or variations in the expression of transforming growth factor beta signaling components. Mutation studies were done through reverse transcription (RT) PCR, single strand conformation polymorphism analysis and automated DNA sequencing. Expression studies were carried out by semi quantitative RT PCR and western blotting. DNA binding ability of Smad complexes and expression of downstream targets were also analyzed.

RESULTS

The six alanine repeat containing variant of TGF-beta RI was seen in 27% of the tumor cases studied, in addition to the 45 bp nucleotide deletions in exon 1 of the receptor in two ovarian tumor samples. A deletion in the polyadenine tract of exon 3 of TGF-beta RII was seen in 22% of the tumor samples. We also report a loss or decrease in the expression of Smad 4 protein in tumor samples with a concurrent loss or reduced DNA binding ability of the Smad complex and deregulated expression of p21 and c-Myc.

CONCLUSIONS

Our results suggest that mutations and/or alterations in expression of TGF-beta receptors and loss of Smad 4 are frequent in human ovarian cancers and may potentially explain the frequent loss of TGF-beta responsiveness that typically occurs in human ovarian cancer.

Ovarian cancer: pathology, biology, and disease models

Epithelial ovarian cancer, which comprises several histologic types and grades, is the most lethal cancer among women in the United States. In this review, we summarize recent progress in understanding the pathology and biology of this disease and in development of models for preclinical research. Our new understanding of this disease suggests new targets for therapeutic intervention and novel markers for early detection of disease.

Immunohistochemical profiling of benign, low malignant potential and low grade serous epithelial ovarian tumors

Background

Serous epithelial ovarian tumors can be subdivided into benign (BOV), low malignant potential (LMP) or borderline and invasive (TOV) tumors. Although the molecular characteristics of serous BOV, LMP and low grade (LG) TOV tumors has been initiated, definitive immunohistochemical markers to distinguish between these tumor types have not been defined.

Methods

In the present study, we used a tissue array composed of 27 BOVs, 78 LMPs and 23 LG TOVs to evaluate the protein expression of a subset of selected candidates identified in our previous studies (Ape1, Set, Ran, Ccne1 and Trail) or known to be implicated in epithelial ovarian cancer disease (p21, Ccnb1, Ckd1).

Results

Statistically significant difference in protein expression was observed for Ccnb1 when BOV tumors were compared to LMP tumors (p = 0.003). When BOV were compared to LG TOV tumors, Trail was significantly expressed at a higher level in malignant tumors (p = 0.01). Expression of p21 was significantly lower in LG tumors when compared with either BOVs (p = 0.03) or LMPs (p = 0.001). We also observed that expression of p21 was higher in LMP tumors with no (p = 0.02) or non-invasive (p = 0.01) implants compared to the LMP associated with invasive implants.

Conclusion

This study represents an extensive analyse of the benign and highly differentiated ovarian disease from an immunohistochemical perspective.

Associations between p53 overexpression and multiple measures of clinical outcome in high-risk, early stage or suboptimally-resected, advanced stage epithelial ovarian cancers A Gynecologic Oncology Group study

OBJECTIVE

The Gynecologic Oncology Group (GOG) performed a detailed analysis of p53 overexpression in previously-untreated women with invasive early or advanced stage epithelial ovarian cancer (EOC).

METHODS

Women were eligible for the study if they provided a tumor block for translational research and participated in either GOG-157, a randomized phase III trial of three versus (vs.) six cycles of paclitaxel+carboplatin in high-risk, early stage EOC, or GOG-111, a randomized phase III trial of cyclophosphamide+cisplatin vs. paclitaxel+cisplatin in suboptimally-resected, advanced stage EOC. The N-terminal DO-7 p53 antibody was used to examine the expression of the major normal and mutant p53-isoforms. p53 overexpression was defined as >or=10% tumor cells exhibiting nuclear staining.

RESULTS

p53 was overexpressed in 51% (73/143) and 66% (90/136) of cases in the GOG-157 and GOG-111 cohorts, respectively. In the GOG-157 cohort, p53 overexpression was not associated with any clinical characteristics or overall survival (OS) but was associated with worse progression-free survival (PFS) (logrank test: p=0.013; unadjusted Cox modeling: p=0.015). In the GOG-111 cohort, p53 overexpression was associated with GOG performance status (p=0.018) and grade (p=0.003), but not with age, stage, cell type or with tumor response and disease status after primary chemotherapy, PFS or OS. Adjusted Cox regression modeling demonstrated that p53 overexpression was not an independent prognostic factor for PFS or OS in either cohort.

CONCLUSIONS

p53 overexpression assessed by DO-7 immunostaining is common in early and advanced stage EOC, but has limited prognostic value in women treated with surgical staging and platinum-based combination chemotherapy.

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.

Distribution of p53 expression in tissue from 774 Danish ovarian tumour patients and its prognostic significance in ovarian carcinomas

The clinical roles played by normal and altered p53 in cancer are under intensive investigation, but larger studies describing the pattern as well as the prognostic value are still needed. The aim of this study was, using tissue array (TA), to examine the overexpression of p53 protein in 774 epithelial ovarian tumour tissues from Danish women and to evaluate whether p53 tissue expression levels correlate with clinicopathological parameters and prognosis. The distribution of p53 expression levels at different stages of disease, in different histological subtypes, and the prognostic value of p53 tissue expression were examined. Overall, p53 was expressed in 24/189 (13%) low malignant potential ovarian tumours (LMP) and in 278/585 (48%) ovarian cancers (OC). No significant difference in frequency of p53 tissue expression in LMP tissue was noted with increasing tumour stage (p=0.98). By contrast, there was a significant increase in the frequency of p53 tissue expression in OC with increasing FIGO stage (p<0.00001). Multivariate Cox regression analysis found that less than 20% tissue expression of p53 was associated with longer OC disease-specific survival. Tissue p53 expression may be of prognostic value in women with OC.

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.

Alterations in the p53 pathway and prognosis in advanced ovarian cancer: a multi-factorial analysis of the EORTC Gynaecological Cancer group (study 55865)

PURPOSE

The study was designed to determine independent prognostic variables in suboptimally debulked advanced ovarian cancer patients entered in the randomised phase III study EORTC 55865.

EXPERIMENTAL DESIGN

Retrospectively collected paraffin blocks from 169 patients with stages IIb-IV epithelial ovarian cancer, taken at primary debulking surgery, were analysed. All patients were treated with cyclophosphamide and cisplatin (CP), and followed up for a median of 10 years. Expression of p53, bcl-2, P21, Ki-67 and HER-2 status was assessed by immunohistochemistry (IHC).

RESULTS

Expression of p21, a downstream effector of the p53 gene, was found to be a favourable prognostic factor for survival (HR 0.58, CI 0.36-0.94, p=0.025) in addition to FIGO stage (HR 1.54, CI 1.08-2.21, p=or<0.02). For progression free survival (PFS), both p21 (HR 0.52) and Ki-67 (HR 0.6) were significant factors.

CONCLUSION

P21 overexpression is a positive prognostic factor for survival and PFS in advanced ovarian carcinoma with residual lesions of more than 1 cm.

Molecular predictors of response and outcome in ovarian cancer

A major problem in clinical management of patients with epithelial ovarian cancer (EOC) is the largely unpredictable response to first-line treatment and the occurrence of relapse after complete initial response, associated with broad cross-resistance to even structurally dissimilar drugs. During tumor development and progression, multiple genic alterations take place that might contribute specifically to the treatment response and eventually impact on disease outcome. One area of intense research is the identification of molecular markers to accurately assess the prognosis of EOC patients and to define innovative therapeutic strategies. A large survey of recent published data indicates the need to revisit traditional molecular markers with respect to their contribution to the assessment of overall survival in selected populations. Furthermore, recent technological developments that enable simultaneous measurement of many parameters ("omic" approaches) hold the promise of identifying new molecular prognostic and predictive markers.

Genetic dissection of apoptosis and cell cycle control in response of colorectal cancer treated with preoperative radiochemotherapy

Background

In previous analyses we identified therapy-induced upregulation of the CDK inhibitor p21^CIP/WAF-1 and consequently decreased tumor cell proliferation or loss of Bax as adverse factors for survival in rectal cancer treated with radiochemotherapy. Here, we address the individual role of p53 and its transcriptional targets, p21^CIP/WAF-1 and Bax, on apoptosis induced by individual components of multimodal anticancer therapy, i.e. 5-fluorouracil (5-FU), ionising γ-radiation (IR) and heat shock/hyperthermia.

Methods

We analysed tumor samples 66 patients with rectal carcinoma treated by a neoadjuvant approach with radiochemotherapy ± heat shock/hyperthermia for the expression and mutation of p53 and the expression of p21^CIP/WAF-1 and Bax. These data were correlated with the tumor response. The functional relevance of p53, p21^CIP/WAF-1 and Bax was investigated in isogeneic HCT116 cell mutants treated with 5-FU, IR and heat shock.

Results

Rectal carcinoma patients who received an optimal heat shock treatment showed a response that correlated well with Bax expression (p = 0.018). Local tumor response in the whole cohort was linked to expression of p21^CIP/WAF-1 (p < 0.05), but not p53 expression or mutation. This dichotomy of p53 pathway components regulating response to therapy was confirmed in vitro. In isogeneic HCT116 cell mutants, loss of Bax but not p53 or p21^CIP/WAF-1 resulted in resistance against heat shock. In contrast, loss of p21^CIP/WAF-1 or, to a lesser extent, p53 sensitized predominantly for 5-FU and IR.

Conclusion

These data establish a different impact of p53 pathway components on treatment responses. While chemotherapy and IR depend primarily on cell cycle control and p21, heat shock depends primarily on Bax. In contrast, p53 status poorly correlates with response. These analyses therefore provide a rational approach for dissecting the mode of action of single treatment modalities that may be employed to circumvent clinically relevant resistance mechanisms in rectal cancer.

Correlations between c-myc gene copy-number and clinicopathological parameters of ovarian tumours

The objective of this study was to investigate increases in c-myc gene copy-number in ovarian tumours, and to analyze their correlations with clinicopathological parameters. Here we applied FISH on TMA (tissue microarrays) containing 507 ovarian tumour samples from different malignancy, histology, stage and grade. Overall, we found high frequency for c-myc copy-number increases (38.5%) in ovarian cancers: 22.1% amplifications and 16.4% gains. We established c-myc amplification in more than 30% in endometrioid and mixed epithelial ovarian carcinomas. c-myc gains were found in a high proportion (42.9%) of clear cell carcinomas. We found associations between c-myc copy-number changes and clinicopathological parameters of ovarian tumours such as degree of malignancy and histological type. We suggested that c-myc amplifications are characteristics for endometrioid, and c-myc gains for clear cell ovarian cancers. We suggest that copy-number increases of c-myc and 20q13.2 represent a possible mechanism for the regulation of the pathway STK15--c-myc--hTERT.

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.

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.

Retinoid receptors in ovarian cancer: expression and prognosis

BACKGROUND

Ovarian cancer is frequently lethal despite aggressive multimodal therapy, and new therapies are therefore needed. Retinoids are potential candidate drugs: they prevent the development of ovarian carcinoma and enhance the efficacy of cytotoxic drugs in ovarian cancer cells. At present, little is known about the retinoid receptor expression in ovarian cancer.

PATIENTS AND METHODS

The retinoid receptors comprise two classes, retinoic acid receptors (RARs) and retinoid X receptors (RXRs), each with three subclasses, alpha, beta and gamma. We investigated the expression of the subtypes RARalpha, RARgamma, RXRalpha and RXRbeta by immunohistochemistry in ovarian cancers of 80 patients, and assessed their prognostic significance. In addition, we quantified the expression of retinoid receptor mRNA using real-time PCR and correlated the results with clinical characteristics.

RESULTS

RARalpha and RXRbeta were highly expressed in a majority of ovarian cancers, particularly in advanced stages. High expression of RARalpha was an independent negative prognostic factor of survival in addition to FIGO stage, age and p53 accumulation. The mRNA expression of retinoid receptors did not correlate with clinical properties of the tumors.

CONCLUSIONS

Retinoic acid receptors are frequently and strongly expressed in epithelial ovarian cancer and may be indicators of an adverse prognosis. This study provides the molecular basis for the therapeutic use of retinoids in ovarian cancer.

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.

The cyclin-dependent kinase inhibitor p21cip1/waf1 enhances the cytotoxicity of ganciclovir in HSV-tk transfected ovarian carcinoma cells

Suicide gene therapy could be an attractive addition to the treatment of ovarian carcinomas, for which acquired chemoresistance frequently results in treatment failure. Here we show that transfection of the HSV-tk gene, followed by incubation with up to 1 mM ganciclovir fails to induce cell death in SKOV3 chemoresistant human ovarian carcinoma cells. However, co-transfection of HSV-tk with Cip1/Waf1 encoding the p21(cip1/waf1) inhibitor of cdks, allows 100 microM ganciclovir to eradicate the population of tumor cells. Potentiation of a drug by co-transfer of HSV-tk with Cip1/Waf1could thus represent another therapeutic approach for tumours that are resistant to conventional therapy.

Expression of the c-myc gene as a predictor of chemotherapy response and a prognostic factor in patients with ovarian cancer

The present study was conducted to determine whether and how expression of the c-myc gene is related to the response to chemotherapy in patients with epithelial ovarian cancer. This study includes 101 consecutive patients with stage Ic to IV epithelial ovarian cancer who underwent primary surgery followed by platinum-based chemotherapy. Immunohistochemical studies were performed to detect Ki-67 and ARF proteins. Apoptotic cells were identified by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick-end labeling method. Mutation of the p53 gene was screened by polymerase chain reaction (PCR)-single strand conformation polymorphism analysis and confirmed by direct sequencing. mRNA expression of c-myc was determined by means of reverse transcription-PCR. Apoptotic index (AI) and ARF labeling index (LI) were significantly increased and Ki-67 LI was decreased after chemotherapy in patients from whom specimens could be obtained before and after chemotherapy. AI, ARF LI, and Ki-67 LI were not related to p53 gene status. A significant correlation between expression of c-myc and ARF LI was observed. Of 38 patients with measurable lesion, 23 (60.5%) responded to chemotherapy and 15 (39.5%) did not. Tumors with the wild-type p53 gene responded significantly better to chemotherapy than did tumors with the mutation. Responders showed a higher expression of c-myc than nonresponders (468 +/- 76 vs. 187 +/- 68). The receiver operating characteristic (ROC) curve according to chemoresponse demonstrated that the cut-off value of c-myc expression was 200. Patients with c-myc expression of more than 200 had a better 5-year survival rate (69.8% vs. 43.5%; 101 patients). Multivariate analysis revealed that c-myc expression was an independent prognostic factor. Our results suggest that the expression of c-myc gene is related to chemoresponse and might be a useful prognostic factor in patients with epithelial ovarian cancer.