p53 and mdm2 as prognostic indicators in patients with epithelial ovarian cancer: a multivariate analysis

Immunohistological localization of MDM2, MCM2, Fascin, PCNA, EGFR in paraffin section; in the normal and cancerous human ovary

BACKGROUND

Many protein markers have been investigated in human tissues such as; Fascin, MDM2, MCM2, EGFR, and PCNA. These markers have important physiologic roles in cell proliferation, motility, adhesion, invasion, and survival.

AIMS

up to date, some researchers focused on these markers in ovarian cancer. However, the mentioned markers have not been investigated in the normal human ovary. Using the immunohistochemical technique we tried to localize these markers in the normal, and cancerous ovarian tissues.

METHODS

Paraffin-embedded from 10 normal ovarian tissue and 1 case with histologically confirmed ovarian cancer, underwent an immunohistological process, and five mentioned markers were localized in the human ovary. At first, each marker presentation was assessed and then it tried to quantify the amount of presentation.

RESULTS

Fascin, PCNA, and MCM2 are presented high in the normal ovarian tissue, while EGFR is restricted to the epithelium and very rarely in the granulosa cells. Also, MDM2 was negative for all normal ovaries. All markers had overexpression in ovarian cancer in different patterns.

CONCLUSION

Ovarian cancer tissue showed over-expression of the cell proliferation and motility markers compared with the normal ovary. These markers may have prognostic value in ovarian cancer.

Alpha Mangostin and Cisplatin as Modulators of Exosomal Interaction of Ovarian Cancer Cell with Fibroblasts

The diversity of exosomes and their role in the microenvironment make them an important point of interest in the development of cancer. In our study, we evaluated the effect of exosomes derived from ovarian cancer cells on gene expression in fibroblasts, including genes involved in metastasis. We also attempted to evaluate the indirect effect of cisplatin and/or α-mangostin on metastasis. In this aspect, we verified the changes induced by the drugs we tested on vesicular transfer associated with the release of exosomes by cells. We isolated exosomes from ovarian cancer cells treated and untreated with drugs, and then normal human fibroblasts were treated with the isolated exosomes. Changes in the expression of genes involved in the metastasis process were then examined. In our study, we observed altered expression of genes involved in various steps of the metastasis process (including genes related to cell adhesion, genes related to the interaction with the extracellular matrix, the cell cycle, cell growth and proliferation, and apoptosis). We have shown that α-mangostin and/or cisplatin, as chemotherapeutic agents, not only directly affect tumor cells but may also indirectly (via exosomes) contribute to delaying metastasis development.

Gain-of-Function Mutant TP53 R248Q Overexpressed in Epithelial Ovarian Carcinoma Alters AKT-Dependent Regulation of Intercellular Trafficking in Responses to EGFR/MDM2 Inhibitor

As the most common gene mutation found in cancers, p53 mutations are detected in up to 96% of high-grade serous ovarian carcinoma (HGSOC). Meanwhile, mutant p53 overexpression is known to drive oncogenic phenotypes in cancer patients and to sustain the activation of EGFR signaling. Previously, we have demonstrated that the combined inhibition of EGFR and MDM2-p53 pathways, by gefitinib and JNJ-26854165, exerts a strong synergistic lethal effect on HGSOC cells. In this study, we investigated whether the gain-of-function p53 mutation (p53^R248Q) overexpression could affect EGFR-related signaling and the corresponding drug inhibition outcome in HGSOC. The targeted inhibition responses of gefitinib and JNJ-26854165, in p53^R248Q-overexpressing cells, were extensively evaluated. We found that the phosphorylation of AKT increased when p53^R248Q was transiently overexpressed. Immunocytochemistry analysis further showed that upon p53^R248Q overexpression, several AKT-related regulatory proteins translocated in unique intracellular patterns. Subsequent analysis revealed that, under the combined inhibition of gefitinib and JNJ-26854165, the cytonuclear trafficking of EGFR and MDM2 was disrupted. Next, we analyzed the gefitinib and JNJ-26854165 responses and found differential sensitivity to the single- or combined-drug inhibitions in p53^R248Q-overexpressing cells. Our findings suggested that the R248Q mutation of p53 in HGSOC caused significant changes in signaling protein function and trafficking, under EGFR/MDM2-targeted inhibition. Such knowledge could help to advance our understanding of the role of mutant p53 in ovarian carcinoma and to improve the prognosis of patients receiving EGFR/MDM2-targeted therapies.

Human La Protein: An RNA-Binding Protein Involved in Ovarian Cancer Development and Multidrug Resistance

Multidrug resistance is the main cause of chemotherapy failure and death in patients with advanced ovarian cancer. Drug resistance is a problem that must be solved to improve the survival rate of patients with advanced ovarian cancer. The RNA-binding protein La and the La-related protein family are highly expressed in various malignant tumors, including ovarian cancer. This article reviews the mechanisms of La protein in tumorigenesis, development, and drug resistance. High La protein expression in tumor cells promotes tumor proliferation, invasion, and migration; disrupts cell cycle; and inhibits tumor cell apoptosis caused by chemotherapeutic drugs through various pathways, resulting in chemotherapy resistance in ovarian cancer. Further study of the role of La protein in ovarian cancer multidrug resistance may be conducive to the development of human La protein-specific inhibitors that suppress ovarian cancer drug resistance.

Th17-inducing autologous dendritic cell vaccination promotes antigen-specific cellular and humoral immunity in ovarian cancer patients

In ovarian cancer (OC), IL-17-producing T cells (Th17s) predict improved survival, whereas regulatory T cells predict poorer survival. We previously developed a vaccine whereby patient-derived dendritic cells (DCs) are programmed to induce Th17 responses to the OC antigen folate receptor alpha (FRα). Here we report the results of a single-arm open-label phase I clinical trial designed to determine vaccine safety and tolerability (primary outcomes) and recurrence-free survival (secondary outcome). Immunogenicity is also evaluated. Recruitment is complete with a total of 19 Stage IIIC-IV OC patients in first remission after conventional therapy. DCs are generated using our Th17-inducing protocol and are pulsed with HLA class II epitopes from FRα. Mature antigen-loaded DCs are injected intradermally. All patients have completed study-related interventions. No grade 3 or higher adverse events are seen. Vaccination results in the development of Th1, Th17, and antibody responses to FRα in the majority of patients. Th1 and antibody responses are associated with prolonged recurrence-free survival. Antibody-dependent cell-mediated cytotoxic activity against FRα is also associated with prolonged RFS. Of 18 patients evaluable for efficacy, 39% (7/18) remain recurrence-free at the time of data censoring, with a median follow-up of 49.2 months. Thus, vaccination with Th17-inducing FRα-loaded DCs is safe, induces antigen-specific immunity, and is associated with prolonged remission.

The Analysis of Cell Cycle-related Proteins in Ovarian Clear Cell Carcinoma Versus High-grade Serous Carcinoma

In Japan, the frequency of ovarian clear cell carcinoma (CCC) is twice as high as that in the United States and Europe. Often, patient prognosis with CCC is poor because of chemoresistance. Here, we focus on the cell cycle, which is one of the mechanisms of chemoresistance. To detect the informative markers and improve the strategy of chemotherapy for CCC, we performed immunohistochemical staining of cell cycle-related proteins in ovarian malignant tumors. We detected that each of the 29 samples of CCC and high-grade serous carcinoma (HGSC) were necessary to reveal the significant differences in immunostaining and prognosis. We performed the immunostaining analysis using the antibodies of cell cycle-related proteins such as Ki-67, Cdt1, MCM7, and geminin. The positive rate of Cdt1 in the CCC group was significantly higher than that in the HGSC group (P<0.0001). However, the positive rate of geminin in the HGSC group was significantly higher than that in the CCC group (P<0.0001). The overall survival of CCC patients with high labeling index of Cdt1 was significantly worse than that of CCC patients with low labeling index of Cdt1 (P=0.004). The study results suggested that the cancer cells of CCC and HGSC exist in the G1 phase and S, G2, and M phases, respectively. The differences in cell cycle of CCC might be one of the reasons for chemotherapy resistance. Further investigations are necessary to reveal the usefulness of Cdt1 as a biomarker in CCC.

Contribution of Immunohistochemistry in Prognostic Assessment of Epithelial Ovarian Carcinoma – Review of the Literature I

Epithelial ovarian carcinoma is worldwide the sixth most common female cancer, and this malignancy carries the highest mortality among all gynecological cancers. The high mortality is due mostly to the fact that the tumor is frequently diagnosed late, in advanced stage, as the early disease is often asymptomatic and no effective screening methods are available. The most important prognostic factors in ovarian carcinoma are the stage, size of residual tumor following surgery, presence of ascites, age and the general condition of the patient, tumor histology, and, in patients with early disease, also the grade of the tumor. Large number of studies on prognostic and predictive factors in epithelial ovarian carcinoma has been published, often with contradictory results. The most intensely studied prognostic factors are those for expression of hormonal receptors, for tumor proliferation activity (mainly by antigen Ki-67 and topoisomerase IIα), the markers of apoptosis (p53, p21, mdm2, bcl-2 and other proteins), or other oncoproteins (particularly HER-2/neu).

Prognostic role of excision repair cross complementing-1 and topoisomerase-1 expression in epithelial ovarian cancer

OBJECTIVE

Epithelial ovarian cancer is the most lethal gynecologic cancer worldwide and chemoresistance is one of the major causes of treatment failure. We investigated whether ERCC1, TAU, TOPO2A, TOPO1, P53, and C-MYC expression could be used as predictors for treatment outcomes.

MATERIALS AND METHODS

Immunohistochemical staining was used to examine the expression of these biomarkers in resected tumor specimens from 38 patients treated in our institute. Clinicopathological data including demographics, staging, histological type, treatment response, expression of the biomarkers, and patient outcomes were analyzed.

RESULTS

The median follow-up period was 47.5 months (range, 10-135 months) and the median overall survival was 56.0 months. Patients who did not have expression of ERCC1, and those who had expression of TOPO1 had significantly better overall survival. Cox regression analysis also confirmed that these two biomarkers were significant independent factors predicting survival (ERCC1, hazard ratio 5.51, 95% confidence interval: 2.02-14.00, p = 0.001; TOPO1, hazard ratio 0.22, 95% confidence interval: 0.06-0.77, p = 0.017).

CONCLUSION

We concluded that poor overall survival was significantly associated with positive ERCC1 and negative TOPO1 expression. The results might be the consequence of chemoresistance to platinum and camptothecins, both of which are commonly used regimens in the treatment of epithelial ovarian cancer.

Prediction of Optimal Cytoreductive Surgery of Serous Ovarian Cancer With Gene Expression Data

OBJECTIVES

Cytoreductive surgery is the cornerstone of ovarian cancer (OVCA) treatment. Detractors of initial maximal surgical effort argue that aggressive tumor biology will dictate survival, not the surgical effort. We investigated the role of biology in achieving optimal cytoreduction in serous OVCA using microarray gene expression analysis.

METHODS

For the initial model, we used a gene expression signature from a microarray expression analysis of 124 women with serous OVCA, defining optimal cytoreduction as removal of all disease greater than 1 cm (with 64 women having optimal and 60 suboptimal cytoreduction). We then applied this model to 2 independent data sets: the Australian Ovarian Cancer Study (AOCS; 190 samples) and The Cancer Genome Atlas (TCGA; 468 samples). We performed a second analysis, defining optimal cytoreduction as removal of all disease to microscopic residual, using data from AOCS to create the gene signature and validating results in TCGA data set.

RESULTS

Of the 12,718 genes included in the initial analysis, 58 predicted accuracy of cytoreductive surgery 69% of the time (P = 0.005). The performance of this classifier, measured by the area under the receiver operating characteristic curve, was 73%. When applied to TCGA and AOCS, accuracy was 56% (P = 0.16) and 62% (P = 0.01), respectively, with performance at 57% and 65%, respectively. In the second analysis, 220 genes predicted accuracy of cytoreductive surgery in the AOCS set 74% of the time, with performance of 73%. When these results were validated in TCGA set, accuracy was 57% (P = 0.31) and performance was at 62%.

CONCLUSION

Gene expression data, used as a proxy of tumor biology, do not predict accurately nor consistently the ability to perform optimal cytoreductive surgery. Other factors, including surgical effort, may also explain part of the model. Additional studies integrating more biological and clinical data may improve the prediction model.

P53, MAPK, topoisomerase II alpha and Ki67 immunohistochemical expression and KRAS/BRAF mutation in ovarian serous carcinomas

Background

We investigated the immunohistochemical expression of p53, MAPK, topoisomerase II alpha (topoII alpha) and Ki67 in ovarian serous carcinomas (OSCs) along with mutational analysis for KRAS and BRAF.

Methods

Eighty one cases of OSCs were reviewed and examined immunohistochemically using antibodies against p53, MAPK, topoII alpha and Ki67. Staining was evaluated as a percentage of immunopositive cells with cut-off levels at 10% for p53 and topoII alpha, and 5% for MAPK. The Ki67 immunoexpression was assessed by means of Olympus Image Analysis System as a percentage of immunopositive cells in 1000 tumor cells. KRAS and BRAF mutational analysis was performed on 73 available microdissected samples.

Results

Of 81 cases of OSCs 13.6% were of low-grade and 86.4% were of high-grade morphology. In the high-grade group there was a significantly higher immunoexpression of p53 (P < 0.001) and topoII alpha (P = 0.001), with Ki67 median 56.5 vs. 19 in low-grade group (P < 0.001). The difference in immunoexpression of active MAPK between low- and high-grade group was also significant (P = 0.003). MAPK positive immunostaining was detected in 63.6% of low-grade vs. 17.1% of high-grade OSCs. The frequency of KRAS mutation was significantly higher in low-grade as compared to high-grade group (P = 0.006). None of the samples had BRAF mutation. In addition, we detected positive MAPK immunoexpression in 13/59 samples with wild-type KRAS, suggesting that activation of MAPK pathway is not ultimately related either to KRAS or BRAF mutation. Seven morphologically high-grade samples (11.7%) showed both KRAS mutation and p53 immunopositivity.

Conclusions

Although this study is limited by its humble number of low-grade samples, our data fit the proposed dualistic pathway of ovarian carcinogenesis. Mutational analysis for KRAS and BRAF discloses some possible interactions between different tumorigenic pathways of low- and high-grade carcinomas. Immunohistochemical staining for MAPK was not sufficiently sensitive, nor specific, to precisely predict the KRAS mutation. However, it appears to be quite reliable in ruling out a KRAS mutation if the staining is negative.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9283563368804632

Zusammenfassung

Hintergrund

Wir untersuchten die Immunohistochemische Expression der p53, MAPK, topoisomerase II alpha (topoII alpha) und Ki67 in Ovarialkarzinomen (OSCs) anbei mit Mutationsanalyse für KRAS und BRAF.

Methode

81 OSCs Fälle wurden analysiert und Immunohistochemisch untersucht mit Antikörper gegen p53, MAPK, topoII alpha und Ki67. Die Färbung war ausgewertet als der Prozent von immunopositiven Zellen mit den “cut-of” Niveau an 10% für p53 und topoII alpha und 5% für MAPK. Die Ki67 Expression war bewertet mittels Olympus Image Analysis System als der Prozent von immunopositiven Zellen in 1000 Tumorzellen. KRAS and BRAF Mutationsanalyse wurde in 73 verfügbaren microdissections Stichproben aufgeführt.

Ergebnisse

Von 81 OSCs Fälle 13.6% zeigte “low-grade” und 86.4% “high-grade” Morphologie. In der “high-grade” Gruppe war eine statistisch bedeutende höhere Expression von p53 (P < 0.001) und topoII alpha (P = 0.001) mit Ki67 median von 56.5 im Gegensatz zu 19 in der “low-grade” Gruppe (P < 0.001). Die Differenz in Immunoexpression von aktiver MAPK zwischen der “low-grade” und “high-grade” Gruppe war statistisch bedeutend (P = 0.003). MAPK positive Expression war in 63.6% der “low-grade” im Gegensatz von 17.1% der “high-grade” Karzinoms bemerkt. Die Häufigkeit der KRAS Mutation war bedeutend höher in “low-grade” im Verglich zu der “high-grade” Gruppe (P = 0.006). Keiner der Stichproben hate BRAF Mutation. Wir haben auch eine positive MAPK Expression in 13/59 der Stichproben mit “wild-type” KRAS bemerkt, was sugeriert das die Aktivation des MAPK Pfads ist nicht letztmalig mit KRAS oder BRAF verbunden. Sieben der “high-grade” Stichproben (11.7%) waren KRAS Mutation und p53 Expression positive.

Schlussworte

Obwohl diese Studie mit bescheiden Nummer von “low-grade” Stichproben limitiert ist, unsere Daten passen in das dualistische Modell von Ovarial Karzinogenesis. Mutationsanalyse für KRAS und BRAF enthüllen einige mögliche Interaktionen zwischen verschieden tumorigenen Wege von “low”- and “high-grade” Karcinomen.

Die Immunohistochemische Expression für MAPK war nicht empfindlich oder spezifisch genüg um den KRAS mutations Status des Tumor genau vorauszusagen.

Es scheint das die MAPK Expression ziemlich verlässlich ist in ausschließen der KRAS Mutation, wenn die Expression negative ist.

The genomic landscape of TP53 and p53 annotated high grade ovarian serous carcinomas from a defined founder population associated with patient outcome

High-grade ovarian serous carcinomas (HGSC) are characterized by TP53 mutations and non-random patterns of chromosomal anomalies, where the nature of the TP53 mutation may correlate with clinical outcome. However, the frequency of common somatic genomic events occurring in HGSCs from demographically defined populations has not been explored. Whole genome SNP array, and TP53 mutation, gene and protein expression analyses were assessed in 87 confirmed HGSC samples with clinical correlates from French Canadians, a population exhibiting strong founder effects, and results were compared with independent reports describing similar analyses from unselected populations. TP53 mutations were identified in 91% of HGSCs. Anomalies observed in more than 50% of TP53 mutation-positive HGSCs involved gains of 3q, 8q and 20q, and losses of 4q, 5q, 6q, 8p, 13q, 16q, 17p, 17q, 22q and Xp. Nearly 400 regions of non-overlapping amplification or deletion were identified, where 178 amplifications and 98 deletions involved known genes. The subgroup expressing mutant p53 protein exhibited significantly prolonged overall and disease-free survival as compared with the p53 protein null subgroup. Interestingly, a comparative analysis of genomic landscapes revealed a significant enrichment of gains involving 1q, 8q, and 12p intervals in the subgroup expressing mutant p53 protein as compared with the p53 protein null subgroup. Although the findings show that the frequency of TP53 mutations and the genomic landscapes observed in French Canadian samples were similar to those reported for samples from unselected populations, there were differences in the magnitude of global gains/losses of specific chromosomal arms and in the spectrum of amplifications and deletions involving focal regions in individual samples. The findings from our comparative genomic analyses also support the notion that there may be biological differences between HGSCs that could be related to the nature of the TP53 mutation.

Does tumour biology determine surgical success in the treatment of epithelial ovarian cancer? A systematic literature review

Background:

Ovarian cancer is the most lethal gynaecological cancer. Progression-free and overall survival is significantly related to surgical success and residual disease volume. It is unclear whether this survival advantage is due to an intrinsic biological element of the tumour cells which enables successful surgery and improved prognosis, or alternatively the number of tumour sustaining cells remaining irrespective of differences in biology.

Methods:

A systematic review of the literature was performed identifying studies that have investigated the association between biomarkers and surgical outcomes. We attempted validation of these results using The Cancer Genome Atlas ovarian cancer data sets.

Results:

Thirty studies were identified of which sixteen determined protein expression, eight gene expression and one DNA methylation in association with surgical debulking. Individualised linear models adjusting for batch, stage and age identified only expression of the genes MTDH and insulin-like growth factor-1 receptor (IGF1R) to be significantly associated with debulking surgery (P<0.05, false discovery rate (FDR)<5%), although in the case of IGF1R this was in the opposite direction to previous findings.

Conclusion:

The majority of studies are limited by design, include heterogeneous samples and lack adjustment for major confounding factors. High quality detailed clinical annotations should be routinely collected in future to more accurately evaluate biomarkers of surgical outcome.

Correlation Between Immunohistochemical Biomarkers Expression and Prognosis of Ovarian Carcinomas in Tunisian Patients

Background

Ovarian cancer is the leading cause of death from gynaecological malignancies. Newer biological prognostic factors and predictors of response to therapy are needed. Our study was designed to evaluate the expression of p53, Bcl-2, Estrogen receptor (ER) and Progesterone receptor (PR) in ovarian carcinoma and to compare it with other prognostic parameters such as age, FIGO stage, size of residual tumor, histological type and grade.

Methods

This is a retrospective study conducted in the department of pathology at Sfax University Hospital. Confirmed 57 cases of ovarian carcinoma were reviewed in the period between January 1995 and December 2006. We used immunohistochemistry to evaluate the expression of p53, Bcl-2, ER and PR receptors and Chi-Square and Student test to correlate immunohistochemical findings with some prognostic parameters of ovarian carcinoma.

Results

The percentage of expression of p53, Bcl-2, ER and PR was 73,7; 47,4; 35,1 and 33,3 % respectively. p53 overexpression correlated with an advanced FIGO stage (p = 0,026) and presence of ascitis (p < 10^-4). The expression of PR was associated with an early stage (FIGO I and II), a non serous histologic type and a low tumour grade (p = 0,045; 0,010 and 0,036 respectively). No correlation was found between Bcl-2 and ER and prognostic parameters. Survival analysis revealed that Bcl-2 status, FIGO stage, presence of ascites, peritoneal cytology, and residual disease were significant predictive factors of survival.

Conclusion

p53 expression correlates with a worse prognosis in epithelial ovarian cancer, whereas Bcl-2 expression is related to a better outcome. For hormonal status, expression of PR is found to be an independent indicator of favourable prognosis. These results should be supported by more and larger studies.

Correlation between expression of p53, p21/WAF1, and MDM2 proteins and their prognostic significance in primary hepatocellular carcinoma

Background

Tumor Protein p53 (p53), cyclin-dependent kinase inhibitor 1A (p21/WAF1), and murine double minute 2 (MDM2) participate in the regulation of cell growth. Altered expression of these gene products has been found in malignant tumors and has been associated with poor prognosis. Our aim was to investigate the expression of the 3 proteins in hepatocellular carcinoma (HCC) and their prognostic significance.

Methods

We examined p53, p21/WAF1, and MDM2 expression in 181 pairs of HCC tissues and the adjacent hepatic tissues by performing immunohistochemistry and examined the expression of the 3 proteins in 7 pairs of HCC tissues and the adjacent hepatic tissues by using western blot analysis.

Results

The expression of p53, p21/WAF1, and MDM2 in the HCC tissues was significantly higher than those in the adjacent hepatic tissues (P < 0.05). A statistical correlation was observed between p53 and p21/WAF1 expression in HCC tissues (R = 0.195, P = 0.008). A statistical correlation was observed between expression of p53 and p21/WAF1 (R = 0.380, P = 0.000), p53 and MDM2 (R = 0.299, P = 0.000), p21/WAF1 and MDM2 (R = 0.285, P = 0.000) in 181 liver tissues adjacent to the tumor. Patients with a low pathologic grade HCC (I+II) had a higher tendency to express p53 on tumor cells than the patients with high pathologic grade HCC (III+IV) (P = 0.007). Survival analysis showed that positive p21/WAF1 expression or/and negative MDM2 expression in HCC was a predictor of better survival of patients after tumor resection (P < 0.05).

Conclusions

The proteins p53, p21/WAF1, and MDM2 were overexpressed in all the HCC cases in this study, and p53 and p21/WAF1 overexpression were positively correlated. The expression of p21/WAF1 and MDM2 can be considered as 2 useful indicators for predicting the prognosis of HCC.

Aurora kinases as prognostic biomarkers in ovarian carcinoma

We investigated the expression of Aurora kinases A and B by immunohistochemistry in 68 ovarian carcinomas to analyze their prognostic value. The amplification of AURKA gene by fluorescence in situ hybridization was also assessed. Overall, 58.8% and 85.3% of ovarian carcinomas showed expression of Aurora A and B, respectively. Amplification of AURKA was found in 27.6% of cases examined. Tumors with Aurora A expression showed a lower rate of recurrence than those tumors without Aurora A expression (65% versus 91.7%, P = .019). In the univariate analysis, patients with Aurora A and B expression showed an increased progression-free survival (P = .023 and .06, respectively, log-rank test) and overall survival (P = .03 and .02, respectively, log-rank test). The multivariate analysis adjusted to optimal surgery by Cox proportional hazards regression showed Aurora A expression as an independent prognostic factor for progression-free survival (P = .03) and overall survival (P = .02). In conclusion, Aurora A expression seems to have a prognostic value in ovarian carcinoma.

Alteration of cell-cycle regulation in epithelial ovarian cancer

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

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.

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.

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.

Characterization of CSOC 882, a novel immortalized ovarian cancer cell line expressing EGFR, HER2, and activated AKT

OBJECTIVE

Only a small number of comprehensively characterized immortalized ovarian cancer cell lines are available for laboratory studies on ovarian cancer. We describe a new ovarian cancer cell line that arose from primary culture of a stage IC, grade III ovarian carcinoma, designated CSOC 882.

METHODS

We characterized CSOC 882 by karyotyping, growth modeling, immunohistochemical staining, immunoblotting, drug sensitivity testing, and xenografting in nude mice.

RESULTS

CSOC 882 possessed an abnormal tetraploid karyotype including loss of one copy of chromosomes 2, 17, 19, and 21, and deletion of 8p21. Growth of CSOC 882 was best modeled using the logistic growth equation revealing an average doubling time of 31 h. CSOC 882 cells expressed vimentin, cytokeratin, p53, BRCA1, EGF receptor, HER2, androgen receptor, estrogen receptor alpha, and progesterone receptor, while no evidence of estrogen receptor beta or factor VIII was observed. Some but not all CSOC 882 cells were positive for CA125 reflecting the primary tumor, which had patchy CA125 staining. Drug sensitivity assays demonstrated that CSOC 882 was more sensitive to cisplatin and carboplatin than SKOV3 and HCC1937 while CSOC 882 and SKOV3 were both sensitive to paclitaxel unlike HCC1937. CSOC 882 xenografts retained the original characteristics of vimentin, cytokeratin, and factor VIII labeling.

CONCLUSIONS

CSOC 882 is an immortalized cell line that has survived more than 130 passages in culture and retained molecular features of the primary tumor from which it was derived. Compared to the most common ovarian carcinoma cell lines, CSOC 882 is a unique resource for genetic and cellular research on ovarian cancer.

Human kallikrein 8 protein is a favorable prognostic marker in ovarian cancer

Human kallikrein 8 (hK8/neuropsin/ovasin; encoded by KLK8) is a steroid hormone-regulated secreted serine protease differentially expressed in ovarian carcinoma. KLK8 mRNA levels are associated with a favorable patient prognosis and hK8 protein levels are elevated in the sera of 62% ovarian cancer patients, suggesting that KLK8/hK8 is a prospective biomarker. Given the above, the aim of the present study was to determine if tissue hK8 bears any prognostic significance in ovarian cancer. Using a newly developed ELISA, hK8 was quantified in 136 ovarian tumor extracts and correlated with clinicopathologic variables and outcome [progression-free survival (PFS); overall survival (OS)] over a median follow-up period of 42 months. hK8 levels in ovarian tumor cytosols ranged from 0 to 478 ng/mg total protein, with a median of 30 ng/mg. An optimal cutoff value of 25.8 ng/mg total protein (74th percentile) was selected based on the ability of hK8 values to predict the PFS of the study population and to categorize tumors as hK8 positive or negative. Women with hK8-positive tumors most often had lower-grade tumors (G1), no residual tumor after surgery, and optimal debulking success (P < 0.05). Univariate and multivariate analyses revealed that patients with hK8-positive tumors had a significantly longer PFS and OS than hK8-negative patients (P < 0.05). Kaplan-Meier survival curves further confirmed a reduced risk of relapse and death in women with hK8-positive tumors (P = 0.001 and P = 0.014, respectively). These results indicate that hK8 is an independent marker of favorable prognosis in ovarian cancer.

Antibody Immunity to the p53 Oncogenic Protein Is a Prognostic Indicator in Ovarian Cancer

Purpose

Presence of intratumoral T-cell infiltration has been linked to improved survival in ovarian cancer patients. We questioned whether antibody immunity specific for ovarian cancer tumor antigens would predict disease outcome. We evaluated humoral immune responses against ovarian cancer antigens p53, HER-2/neu, and topoisomerase IIα.

Patients and Methods

Serum was collected from 104 women (median age, 59 years; range, 34 to 89 years) at the time of their initial definitive surgery for ovarian cancer. Serum was analyzed by enzyme-linked immunosorbent assay for antibodies to p53, HER-2/neu, and topoisomerase IIα proteins. Antibody immunity to tetanus toxoid was assessed as a control. The incidence of humoral immunity at the time of diagnosis to any of these three antigens was tabulated. For patients with advanced-stage disease (III/IV), correlation was made between the presence of tumor-specific immunity at the time of diagnosis and overall survival. Patients were followed for a median of 1.8 years.

Results

Multivariate analysis showed the presence of p53 antibodies to be an independent variable for prediction of overall survival in advanced-stage patients. Overall survival was significantly higher for patients with antibodies to p53 when compared with patients without p53 antibodies (P = .01). The median survival for p53 antibody-positive patients was 51 months (95% CI, 23.5 to 60.5 months) compared with 24 months (95% CI, 19.4 to 28.6 months) for patients without antibodies to p53.

Conclusion

Data presented here demonstrate that advanced stage ovarian cancer patients can have detectable tumor-specific antibody immunity and that immunity to p53 may predict improved overall survival in patients with advanced-stage disease.