Clinical significance of apoptosis-related factors p53, Mdm2, and Bcl-2 in advanced ovarian cancer

Drug-Resistant Epithelial Ovarian Cancer: Current and Future Perspectives

Epithelial ovarian cancer (EOC) is a complex disease with diverse histological subtypes, which, based on the aggressiveness and course of disease progression, have recently been broadly grouped into type I (low-grade serous, endometrioid, clear cell, and mucinous) and type II (high-grade serous, high-grade endometrioid, and undifferentiated carcinomas) categories. Despite substantial differences in pathogenesis, genetics, prognosis, and treatment response, clinical diagnosis and management of EOC remain similar across the subtypes. Debulking surgery combined with platinum-taxol-based chemotherapy serves as the initial treatment for High Grade Serous Ovarian Carcinoma (HGSOC), the most prevalent one, and for other subtypes, but most patients exhibit intrinsic or acquired resistance and recur in short duration. Targeted therapies, such as anti-angiogenics (e.g., bevacizumab) and PARP inhibitors (for BRCA-mutated cancers), offer some success, but therapy resistance, through various mechanisms, poses a significant challenge. This comprehensive chapter delves into emerging strategies to address these challenges, highlighting factors like aberrant miRNAs, metabolism, apoptosis evasion, cancer stem cells, and autophagy, which play pivotal roles in mediating resistance and disease relapse in EOC. Beyond standard treatments, the focus of this study extends to alternate targeted agents, including immunotherapies like checkpoint inhibitors, CAR T cells, and vaccines, as well as inhibitors targeting key oncogenic pathways in EOC. Additionally, this chapter covers disease classification, diagnosis, resistance pathways, standard treatments, and clinical data on various emerging approaches, and advocates for a nuanced and personalized approach tailored to individual subtypes and resistance mechanisms, aiming to enhance therapeutic outcomes across the spectrum of EOC subtypes.

Molecular mechanisms of platinum‑based chemotherapy resistance in ovarian cancer (Review)

Cisplatin is one of the most effective chemotherapy drugs for ovarian cancer, but resistance is common. The initial response to platinum‑based chemotherapy is as high as 80%, but in most advanced patients, final relapse and death are caused by acquired drug resistance. The development of resistance to therapy in ovarian cancer is a significant hindrance to therapeutic efficacy. The resistance of ovarian cancer cells to chemotherapeutic mechanisms is rather complex and includes multidrug resistance, DNA damage repair, cell metabolism, oxidative stress, cell cycle regulation, cancer stem cells, immunity, apoptotic pathways, autophagy and abnormal signaling pathways. The present review provided an update of recent developments in our understanding of the mechanisms of ovarian cancer platinum‑based chemotherapy resistance, discussed current and emerging approaches for targeting these patients and presented challenges associated with these approaches, with a focus on development and overcoming resistance.

Long non-coding RNA FLJ33360 participates in ovarian cancer progression by sponging miR-30b-3p

Background

Long noncoding RNAs (lncRNAs) have been reported to play a key role in the development and progression of human malignancies. FLJ33360 is an lncRNA with unknown functions. This study was designed to determine the clinical significance and mechanism of FLJ33360 in ovarian cancer.

Materials and methods

The clinical significance of FLJ33360 in ovarian cancer was determined using the Gene Expression Profiling Interactive Analysis (GEPIA) database, Kaplan-Meier Plotter database, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and statistical analysis. The regulatory relationships between FLJ33360 and miR-30b-3p were explored through bioinformatics, the Gene Expression Omnibus (GEO) database, the ArrayExpress database and meta-analysis. The possible pathways were predicted using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. In addition, the key target genes were identified using a protein-protein interaction (PPI) network, the Cancer Genome Atlas (TCGA) database, and correlation analysis.

Results

FLJ33360 expression was significantly downregulated in ovarian cancer tissue (P=0.0011) and was closely associated with International Federation of Gynecology and Obstetrics (FIGO) stage (P=0.027) and recurrence (P=0.002). FLJ33360 may have potential value in detecting ovarian cancer (area under the curve =0.793). Function analysis demonstrated that FLJ33360 can act as a molecular sponge of miR-30b-3p to regulate the expression of target genes that are mainly involved in positive regulation of smooth muscle cell migration, the unsaturated fatty acid metabolic process, and positive regulation of the epithelial to mesenchymal transition. Among these target genes, BCL2 is the hub gene.

Conclusion

FLJ33360 is a potential biomarker for early diagnosis and prognostic assessment in ovarian cancer and may regulate the expression of genes by sponging miR-30b-3p and thus participate in the development of ovarian cancer.

Gene expression profiling analysis of ovarian cancer

As a gynecological oncology, ovarian cancer has high incidence and mortality. To study the mechanisms of ovarian cancer, the present study analyzed the GSE37582 microarray. GSE37582 was downloaded from Gene Expression Omnibus and included data from 74 ovarian cancer cases and 47 healthy controls. The differentially-expressed genes (DEGs) were screened using linear models for microarray data package in R and were further screened for functional annotation. Next, Gene Ontology and pathway enrichment analysis of the DEGs was conducted. The interaction associations of the proteins encoded by the DEGs were searched using the Search Tool for the Retrieval of Interacting Genes, and the protein-protein interaction (PPI) network was visualized by Cytoscape. Moreover, module analysis of the PPI network was performed using the BioNet analysis tool in R. A total of 284 DEGs were screened, consisting of 145 upregulated genes and 139 downregulated genes. In particular, downregulated FBJ murine osteosarcoma viral oncogene homolog (FOS) was an oncogene, while downregulated cyclin-dependent kinase inhibitor 1A (CDKN1A) was a tumor suppressor gene and upregulated cluster of differentiation 44 (CD44) was classed as an 'other' gene. The enriched functions included collagen catabolic process, stress-activated mitogen-activated protein kinases cascade and insulin receptor signaling pathway. Meanwhile, FOS (degree, 15), CD44 (degree, 9), B-cell CLL/lymphoma 2 (BCL2; degree, 7), CDKN1A (degree, 7) and matrix metallopeptidase 3 (MMP3; degree, 6) had higher connectivity degrees in the PPI network for the DEGs. These genes may be involved in ovarian cancer by interacting with other genes in the module of the PPI network (e.g., BCL2-FOS, BCL2-CDKN1A, FOS-CDKN1A, FOS-CD44, MMP3-MMP7 and MMP7-CD44). Overall, BCL2, FOS, CDKN1A, CD44, MMP3 and MMP7 may be correlated with ovarian cancer.

Potential impact of (rs 4645878) BAX promoter -248G>A and (rs 1042522) TP53 72Arg>pro polymorphisms on epithelial ovarian cancer patients

BACKGROUND

In India, Epithelial ovarian cancer has emerged as one of the most common malignancies affecting women. Tumor protein 53 (TP53) induces expression of the B cell lymphoma 2-associated X protein (BAX) gene by directly binding to the TP53-binding element in the BAX promoter. Therefore, we hypothesized that single-nucleotide polymorphism of BAX promoter -248G>A and TP53 72Arg>Pro gene may jointly contribute to ovarian cancer risk.

OBJECTIVES

This study aimed at exploring the association of BAX promoter -248G>A and TP53 72Arg>Pro gene polymorphism with risk of developing EOC and its clinicopathological features and to evaluate gene-gene interaction of these two polymorphisms with risk of developing EOC.

MATERIALS

The study was conducted on 70 Epithelial ovarian cancer patients and 70 healthy controls. Genotyping of p53 codon 72 and BAX promoter gene was examined by ASO-PCR and PICA-PCR, respectively. Odds ratios and 95 % confidence intervals were calculated.

RESULTS

We found an increased cancer risk associated with the BAX AA (ORs = 4.1, 95 %, CI = 1.23-13.97) genotype. An increased risk was also associated with the TP53 Pro/Pro (OR = 4.4, 95 % CI = 1.40-13.99) and Arg/Pro genotype (OR = 2.3, 95 % CI = 1.13-4.86). The gene-gene interaction of these polymorphisms increased EOC risk in a more than additive manner (ORs for the presence of both BAX AA and TP53 Arg/Pro genotypes = 8.7, 95 % CI = 1.66-45.48). BAX GG genotype was associated with adverse staging of cancer (P = 0.01).

CONCLUSIONS

The findings suggest that polymorphism of BAX and TP53 genes may be potential genetic modifiers for developing ovarian cancer.

Tissue biomarkers in prognostication of serous ovarian cancer following neoadjuvant chemotherapy

Serous ovarian cancer (SOC) is a significant cause of morbidity and mortality in females with poor prognosis because of advanced stage at presentation. Recently, neoadjuvant chemotherapy (NACT) is being used for management of advanced SOC, but role of tissue biomarkers in prognostication following NACT is not well established. The study was conducted on advanced stage SOC patients (n = 100) that were treated either conventionally (n = 50) or with NACT (n = 50), followed by surgery. In order to evaluate the expression of tissue biomarkers (p53, MIB1, estrogen and progesterone receptors, Her-2/neu, E-cadherin, and Bcl2), immunohistochemistry and semiquantitative scoring were done following morphological examination. Following NACT, significant differences in tumor histomorphology were observed as compared to the native neoplasms. MIB 1 was significantly lower in cases treated with NACT and survival outcome was significantly better in cases with low MIB 1. ER expression was associated with poor overall survival. No other marker displayed any significant difference in expression or correlation with survival between the two groups. Immunophenotype of SOC does not differ significantly in samples from cases treated with NACT, compared to upfront surgically treated cases. The proliferating capacity of the residual tumor cells is less, depicted by low mean MIB1 LI. MIB 1 and ER inversely correlate with survival.

The consequence of oncomorphic TP53 mutations in ovarian cancer

Ovarian cancer is the most lethal gynecological malignancy, with an alarmingly poor prognosis attributed to late detection and chemoresistance. Initially, most tumors respond to chemotherapy but eventually relapse due to the development of drug resistance. Currently, there are no biological markers that can be used to predict patient response to chemotherapy. However, it is clear that mutations in the tumor suppressor gene TP53, which occur in 96% of serous ovarian tumors, alter the core molecular pathways involved in drug response. One subtype of TP53 mutations, widely termed gain-of-function (GOF) mutations, surprisingly converts this protein from a tumor suppressor to an oncogene. We term the resulting change an oncomorphism. In this review, we discuss particular TP53 mutations, including known oncomorphic properties of the resulting mutant p53 proteins. For example, several different oncomorphic mutations have been reported, but each mutation acts in a distinct manner and has a different effect on tumor progression and chemoresistance. An understanding of the pathological pathways altered by each mutation is necessary in order to design appropriate drug interventions for patients suffering from this deadly disease.

A high serum level of M65 is associated with tumour aggressiveness and an unfavourable prognosis for epithelial ovarian cancer

PURPOSE

This study was conducted to determine the clinical significance of serum M30 and M65 in epithelial ovarian cancer (EOC).

METHODS

A total of 56 patients with EOC and 56 healthy women were included in the study. All of the patients received platinum-based chemotherapy. Pretreatment levels of M30 and M65 were measured using the quantitative ELISA method.

RESULTS

The median M30 and M65 serum levels were significantly elevated in the EOC patients compared with the healthy controls (96.7 vs. 69.5, p = 0.028 and 436.4 versus 166.3, p < 0.001, respectively). The cut-off value of 423.4 U/L for M65 determined with ROC analysis, predicted progression with 75.1 % sensitivity and 65.6 % specificity (AUC = 0.708, p = 0.008). Patients with higher M65 levels had shorter progression-free survival (PFS) (p = 0.021). Both M30 and M65 serum levels were significantly higher for serous-type histology (p = 0.001 and p < 0.001, respectively). Increased M65 serum levels were associated with advanced disease (p = 0.005) and higher grade (p = 0.005). Moreover, M65 levels were higher for chemotherapy-resistant patients (p = 0.04). Multivariate analysis revealed that an elevated serum M65 level was the only significant independent prognostic factor (p = 0.039, HR 3.792).

CONCLUSIONS

These results indicated that serum M30 and M65 levels were significantly elevated in patients with EOC compared with healthy women. Particularly, high serum M65 levels were associated with poor prognosis and resistance to platinum-based chemotherapy.

Surface modification on acoustic wave biosensors for enhanced specificity

Changes in mass loading on the surface of acoustic biosensors result in output frequency shifts which provide precise measurements of analytes. Therefore, to detect a particular biomarker, the sensor delay path must be judiciously designed to maximize sensitivity and specificity. B-cell lymphoma 2 protein (Bcl-2) found in urine is under investigation as a biomarker for non-invasive early detection of ovarian cancer. In this study, surface chemistry and biofunctionalization approaches were evaluated for their effectiveness in presenting antibodies for Bcl-2 capture while minimizing non-specific protein adsorption. The optimal combination of sequentially adsorbing protein A/G, anti-Bcl-2 IgG and Pluronic F127 onto a hydrophobic surface provided the greatest signal-to-noise ratio and enabled the reliable detection of Bcl-2 concentrations below that previously identified for early stage ovarian cancer as characterized by a modified ELISA method. Finally, the optimal surface modification was applied to a prototype acoustic device and the frequency shift for a range of Bcl-2 concentration was quantified to demonstrate the effectiveness in surface acoustic wave (SAW)-based detection applications. The surface functionalization approaches demonstrated here to specifically and sensitively detect Bcl-2 in a working ultrasonic MEMS biosensor prototype can easily be modified to detect additional biomarkers and enhance other acoustic biosensors.

A urinary Bcl-2 surface acoustic wave biosensor for early ovarian cancer detection

In this study, the design, fabrication, surface functionalization and experimental characterization of an ultrasonic MEMS biosensor for urinary anti-apoptotic protein B-cell lymphoma 2 (Bcl-2) detection with sub ng/mL sensitivity is presented. It was previously shown that urinary Bcl-2 levels are reliably elevated during early and late stages of ovarian cancer. Our biosensor uses shear horizontal (SH) surface acoustic waves (SAWs) on surface functionalized ST-cut Quartz to quantify the mass loading change by protein adhesion to the delay path. SH-SAWs were generated and received by a pair of micro-fabricated interdigital transducers (IDTs) separated by a judiciously designed delay path. The delay path was surface-functionalized with monoclonal antibodies, ODMS, Protein A/G and Pluronic F127 for optimal Bcl-2 capture with minimal non-specific adsorption. Bcl-2 concentrations were quantified by the resulting resonance frequency shift detected by a custom designed resonator circuit. The target sensitivity for diagnosis and identifying the stage of ovarian cancer was successfully achieved with demonstrated Bcl-2 detection capability of 500 pg/mL. It was also shown that resonance frequency shift increases linearly with increasing Bcl-2 concentration.

An immunohistochemical comparison of P53 and Bcl-2 as apoptotic and MIB1 as proliferative markers in low-grade and high-grade ovarian serous carcinomas

BACKGROUND

Traditionally, ovarian serous carcinomas (OSCs) have been graded using a 3-tiered system, as well differentiated, moderately differentiated, and poorly differentiated. Recently, a 2-tiered system has been proposed depending on the nuclear atypia and mitotic count. The dualistic pathway of ovarian serous carcinogenesis with accumulating molecular genetic evidence forms the basis for this grading system.

OBJECTIVE

To investigate the expression of apoptotic proteins, p53 and bcl-2, and MIB1 index in low-grade and high-grade OSCs.

METHODS

Eighteen cases of low-grade OSCs and 28 cases of high-grade OSCs were stained immunohistochemically with antibodies against p53, bcl-2, and MIB1. For p53 and bcl-2, staining was evaluated on a semiquantitative scale depending on the number of cells showing positivity. For MIB1, the percentage of positive nuclei was calculated.

RESULTS

Of 28 cases of high-grade OSCs, 15 (53.6%) showed 5+ staining with p53 compared with 3 (16.7%) of 18 cases of low-grade OSCs. Of 28 cases of high-grade OSCs, 10 (35.7%) showed 5+ staining with bcl-2 compared with 2 (11.1%) of 18 cases of low-grade OSCs. The mean MIB1 index was 42.1% in high-grade OSCs (range, 10%-90%) in contrast to the 19.4% (range, 10%-40%) in low-grade OSCs. The differences in apoptotic protein expression and proliferative index between the low-grade and high-grade OSCs were statistically significant (P < 0.05).

CONCLUSIONS

The expression of apoptotic markers is higher in high-grade OSCs, which also have a higher proliferative activity compared with those in low-grade OSCs, which supports the dualistic pathway of ovarian serous carcinogenesis.

Multifunctional tumor-targeted polymer-peptide-drug delivery system for treatment of primary and metastatic cancers

PURPOSE

In order to improve drug delivery to drug-resistant ovarian tumors, we constructed a multifunctional polymer-peptide-drug conjugate (PPDC) system for effective treatment of primary and metastatic ovarian cancers.

METHODS

The PPDC consists of the poly(Ethylene Glycol) (PEG) polymeric carrier conjugated via citric acid spacers to anticancer drug (Camptothecin, CPT), tumor targeting moiety (LRHR, a synthetic analog of luteinizing hormone-releasing hormone) and a suppressor of cellular antiapoptotic defense (BH3 peptide). To test the conjugates in vitro and in vivo, cancer cells were isolated from tissue samples obtained from patients with ovarian primary tumor and metastatic malignant ascites.

RESULTS

It was found that cells isolated from malignant ascites were more aggressive in terms of tumor growth and more resistant to chemotherapy when compared with those isolated from primary tumors. PPDC containing two copies of drugs and peptides was most efficient in treatment of primary tumors and intraperitoneal metastases. Multiple treatments with this PPDC led to almost complete regression of primary tumor and prevented growth of malignant ascites.

CONCLUSION

The proposed multifunctional polymeric delivery system which consists of multiple copies of the drug and peptides demonstrated significantly higher antitumor activity in primary and metastatic cancers when compared with drug alone and PEG-CPT conjugate.

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.

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.

Gene expression profiles as prognostic markers in women with ovarian cancer

The purpose was to find a gene expression profile that could distinguish short-term from long-term survivors in our collection of serous epithelial ovarian carcinomas. Furthermore, it should be able to stratify in an external validation set. Such a classifier profile will take us a step forward toward investigations for more individualized therapies and the use of gene expression profiles in the clinical practice. RNA from tumor tissue from 43 Danish patients with serous epithelial ovarian carcinoma (11 International Federation of Gynecology and Obstetrics [FIGO] stage I/II, 32 FIGO stage III/IV) was analyzed using Affymetrix U133 plus 2.0 microarrays. A multistep statistical procedure was applied to the data to find the gene set that optimally split the patients into short-term and long-term survivors in a Kaplan-Meier plot. A 14-gene prognostic profile with the ability to distinguish short-term survivors (median overall survival of 32 months) from long-term survivors (median overall survival not yet reached after a median follow-up of 76 months) with a P value of 3.4 x 10 was found. The prognostic gene set was also able to distinguish short-term from long-term survival in patients with advanced disease. Furthermore, its ability to classify in an external validation set was demonstrated. The identified 14-gene prognostic profile was able to predict survival (short- vs long-term survival) with a strength that is better than any other prognostic factor in epithelial ovarian cancer including FIGO stage. This stratification method may form the basis of determinations for new therapeutic approaches, as patients with poor prognosis could obtain the biggest advantage from new treatment modalities.

Bcl-2 expression is altered with ovarian tumor progression: an immunohistochemical evaluation

Background

Ovarian cancer is the most lethal gynecologic malignancy. The ovarian tumor microenvironment is comprised of tumor cells, surrounding stroma, and circulating lymphocytes, an important component of the immune response, in tumors. Previous reports have shown that the anti-apoptotic protein Bcl-2 is overexpressed in many solid neoplasms, including ovarian cancers, and contributes to neoplastic transformation and drug-resistant disease, resulting in poor clinical outcome. Likewise, studies indicate improved clinical outcome with increased presence of lymphocytes. Therefore, we sought to examine Bcl-2 expression in normal, benign, and cancerous ovarian tissues to determine the potential relationship between epithelial and stromal Bcl-2 expression in conjunction with the presence of lymphocytes for epithelial ovarian tumor progression.

Methods

Ovarian tissue sections were classified as normal (n = 2), benign (n = 17) or cancerous (n = 28) and immunohistochemically stained for Bcl-2. Bcl-2 expression was assessed according to cellular localization, extent, and intensity of staining. The number of lymphocyte nests as well as the number of lymphocytes within these nests was counted.

Results

While Bcl-2 staining remained cytoplasmic, both percent and intensity of epithelial and stromal Bcl-2 staining decreased with tumor progression. Further, the number of lymphocyte nests dramatically increased with tumor progression.

Conclusion

The data suggest alterations in Bcl-2 expression and lymphocyte infiltration correlate with epithelial ovarian cancer progression. Consequently, Bcl-2 expression and lymphocyte status may be important for prognostic outcome or useful targets for therapeutic intervention.

Modest effect of p53, EGFR and HER-2/neu on prognosis in epithelial ovarian cancer: a meta-analysis

BACKGROUND

P53, EGFR and HER-2/neu are the most frequently studied molecular biological parameters in epithelial ovarian cancer, but their prognostic impact is still unequivocal. We performed a meta-analysis to more precisely estimate their prognostic significance.

METHODS

Published studies that investigated the association between p53, EGFR and HER-2/neu status and survival were identified. Meta-analysis was performed using a DerSimonian-Laird model. Publication bias was investigated using funnel plots and sources of heterogeneity were identified using meta-regression analysis.

RESULTS

A total of 62 studies were included for p53, 15 for EGFR and 20 for HER-2/neu. P53, EGFR and HER-2/neu status had a modest effect on overall survival (pooled HR 1.47, 95% CI 1.33-1.61 for p53; HR 1.65, 95% CI 1.25-2.19 for EGFR and HR 1.67, 95% CI 1.34-2.08 for HER-2/neu). Meta-regression analysis for p53 showed that FIGO stage distribution influenced study outcome. For EGFR and HER-2/neu, considerable publication bias was present.

CONCLUSIONS

Although p53, EGFR and HER-2/neu status modestly influences survival, these markers are, by themselves, unlikely to be useful as prognostic markers in clinical practice. Our study highlights the need for well-defined, prospective clinical trials and more complete reporting of results of prognostic factor studies.

Association of MDM2 SNP309, age of onset, and gender in cutaneous melanoma

PURPOSE

In certain cancers, MDM2 SNP309 has been associated with early tumor onset in women. In melanoma, incidence rates are higher in women than in men among individuals less than 40 years of age, but among those older than 50 years of age, melanoma is more frequent in men than in women. To investigate this difference, we examined the association among MDM2 SNP309, age at diagnosis, and gender among melanoma patients.

EXPERIMENTAL DESIGN

Prospectively enrolled melanoma patients (N = 227) were evaluated for MDM2 SNP309 and the related polymorphism, p53 Arg72Pro. DNA was isolated from patient blood samples, and genotypes were analyzed by PCR-restriction fragment length polymorphism. Associations among MDM2 SNP309, p53 Arg72Pro, age at diagnosis, and clinicopathologic features of melanoma were analyzed.

RESULTS

The median age at diagnosis was 13 years earlier among women with a SNP309 GG genotype (46 years) compared with women with TG+TT genotypes (59 years; P = 0.19). Analyses using age dichotomized at each decade indicated that women with a GG genotype had significantly higher risks of being diagnosed with melanoma at ages <50 years compared with women >or=50 years, but not when the comparison was made between women <60 and >or=60 years. At ages <50 years, women with a GG genotype had a 3.89 times greater chance of being diagnosed compared with women with TG+TT genotypes (P = 0.01). Similar observations were not seen among men.

CONCLUSIONS

Our data suggest that MDM2 may play an important role in the development of melanoma in women. The MDM2 SNP309 genotype may help identify women at risk of developing melanoma at a young age.

Effects of the single nucleotide polymorphism at MDM2 309 on breast cancer patients with/without BRCA1/2 mutations

BACKGROUND

A germ line single nucleotide polymorphism (SNP) in the first intron of the gene encoding MDM2 at position 309, an important modulator of p53, has been described. BRCA1/2 mutation have been associated with increased rates of breast cancers with mutated P53. It was shown that the presence of MDM2 309 SNP correlated with younger cancer onset age in individuals with a p53 mutations. The differential effects of this SNP were also linked to estrogen receptor activation. Here we report on our study of 453 Ashkenazi breast cancer patients of whom 180 were positive for the known Ashkenazi BRCA1/2 mutations

METHODS

DNA from breast cancer patients was obtained for analysis of one of the three common BRCA1/2 mutations and MDM2 SNP309. Data regarding cancer onset and death ages was obtained from our database and Statistical analysis was performed using the SPSS statistical package (SPCC Inc., Chicago, IL), and JMP software (SAS Institute, Cary, NC).

RESULTS

The percentage of MDM2 SNP309 in control and BRCA 1/2 population which is similar to that reported for other Jewish Ashkenazi populations at 52.2% for the heterozygotes and 25.0% for MDM2SNP309G/G and 22.8% for MDM2SNP309T/T.There was not a statistical significant difference in median age of disease onset in the different MDM2 SNP309 subgroups of the BRCA1/2 carriers. When we further divided the group into under and above 51 years old ( presumed menopause age) in the BRCA1 positive subset we found that there were less patients of the MDM2SNP309 G/G versus the MDM2SNP309 T/T in the over 51 patient group (p = 0.049). This result has been obtained in a relatively small subgroup and is of borderline statistical significance. Interestingly, in the BRCA1/2 mutation carriers, we found a survival advantage for patients harboring the SNP309 G/G genotype (p = 0.0086) but not for the 272 patients not harbouring this mutations.

CONCLUSION

MDM2SNP309G/G main effect on BRCA1/2 positive mutation carriers is linked to its effect on patients survival. Further research is needed in order to understand the reason for this difference.

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.

Mismatch repair gene polymorphisms and survival in invasive ovarian cancer patients

AIMS

Inherited genetic factors may help partially explain variability of survival length amongst ovarian cancer patients. Of particular interest are genes involved in DNA repair, specifically those involved in mismatch repair (MMR). The aim of this study was to investigate the possible association between the common variants in MMR genes and invasive ovarian cancer overall survival.

METHOD/RESULTS

We examined associations between 44 variants that tag the known common variants (minor allele frequency 0.05) in seven MMR genes (MLH1, MLH3, MSH2, MSH3, MSH6, PMS1 and PMS2) and survival of invasive ovarian cancer patients in three case-control studies from United Kingdom (UK), Denmark and California of United States of America (USA). DNA from up to 1495 women were genotyped. The genotypes of each polymorphism were tested for association with survival using Cox regression analysis stratified by study. A nominally significant association (P=0.04) between genotype and ovarian cancer survival was observed for rs2228006 in PMS2. The per-rare allele hazard ratio (HR 95%CI) was 0.84 (0.71-0.99), however, it was not significant after adjusting for multiple covariants (P=0.47). When the analyses were restricted to serous type ovarian cancer, two SNPs showed marginal significant associations; the per-rare allele HR was 1.3 (1.05-1.6) (P=0.02) for rs1799977 in MLH1 and 1.4 (1.03-1.9) (P=0.04) for rs6151662 in MSH3. Neither was significant after adjusting for multiple covariants.

CONCLUSION

It is unlikely that common variants in the MMR pathways examined have moderate effects on survival after diagnosis with ovarian cancer. Much larger studies would be needed to exclude common variants with small effects.

Gene-expression profiling in epithelial ovarian cancer

DNA-microarray technology has made it possible to simultaneously analyze the expression of thousands of genes in a small sample of tumor tissue. In epithelial ovarian cancer, gene-expression profiling has been used to provide prognostic information, to predict response to first-line platinum-based chemotherapy, and to discriminate between different histologic subtypes. Furthermore, DNA-microarray technology might permit identification of novel markers for early detection of disease and provide insights into the mechanisms of cancer growth and chemotherapy resistance. In this Review, we summarize the contributions of gene-expression profiling to the diagnosis and management of epithelial ovarian cancer and discuss ways in which this technique could become a useful tool in clinical management.

Combination of serum hCG beta and p53 tissue expression defines distinct subgroups of serous ovarian carcinoma

Serous ovarian carcinoma comprises a clinically heterogenous group of tumors, and molecular markers stratifying patients into clinically meaningful subgroups are needed. Numerous markers have been evaluated, but none of them has yet been routinely incorporated into clinical practice. Previously we have found that elevated serum levels of the free beta subunit of human chorionic gonadotropin (hCG beta) and aberrant p53 expression confer poor prognosis in ovarian carcinoma. The aim of our study was to evaluate their combined effect in predicting the outcome of patients with serous ovarian carcinoma. The study material consisted of 173 consecutive patients treated for primary serous ovarian carcinoma in 1 institution between 1990 and 2000. The preoperative serum level of hCG beta was analyzed by a ultrasensitive and specific immunofluorometric assay, and p53 tumor tissue expression by immunohistochemistry using a novel classification. Elevated serum hCG beta (>or=2.0 pmol/L) was detected in 57 (33%) of 173 patients, and aberrant p53 expression in 103 (62%) of 167 interpretable cancers. Elevated hCG beta and aberrant p53 expression were strongly associated with poor prognosis (p < 0.0001 for both). Their additive prognostic effect was marked. Five-year survival was 14% (0-29%) when both markers were aberrant, 44% (29-60%) when either one was aberrant and 82% (70-94%) when both were normal. Preoperative serum hCG beta and tumor tissue p53 expression are feasible markers that divide serous ovarian carcinomas into clinically relevant subgroups.

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.

Effects of recombinant MAP30 on cell proliferation and apoptosis of human colorectal carcinoma LoVo cells

MAP30, an attractive protein isolated from bitter melon, has been previously found to have the anti-tumor and anti-HIV activities. In this study, MAP30 was cloned and expressed and the effects of the recombinant protein on cell proliferation and apoptosis of human colorectal carcinoma LoVo cells were investigated. The results showed that the proliferation of LoVo cells were significantly suppressed by MAP30 in time- and dose-dependent manners at the concentration ranging from 0.67 to 4.67 muM. The apoptotic nuclei of LoVo cells induced by MAP30 were obviously observed, and the genomic degradation was detected by single-cell gel electrophoresis (comet assay). Nuclear condensation and boundary aggregation or split, apoptotic bodies were seen by fluorescence and electron microscopy. The proportion of the periodic tumor cells was altered by MAP30. Sub-G1 curves were displayed by a flow cytometry analysis. Results of northern and western blots showed that the transcription and expression of Bax, a member of pro-apoptotic proteins, were gradually up-regulated as treated time increased. On the contrary, the transcription and expression of Bcl-2, an anti-apoptotic member, were down-regulated. These data provided powerful evidences for the first time that recombinant MAP30 can induce the apoptosis of the human colorectal carcinoma LoVo cells.

TP53 status and taxane-platinum versus platinum-based therapy in ovarian cancer patients: a non-randomized retrospective study

Background

Taxane-platinum therapy (TP) has replaced platinum-based therapy (PC or PAC, DNA damaging chemotherapy) in the postoperative treatment of ovarian cancer patients; however, it is not always effective. TP53 protein plays a differential role in response to DNA-damaging agents and taxanes. We sought to define profiles of patients who benefit the most from TP and also of those who can be treated with PC.

Methods

We compared the effectiveness of PC/PAC (n = 253) and TP (n = 199) with respect to tumor TP53 accumulation in ovarian cancer patients with FIGO stage IIB-IV disease; this was a non-randomized retrospective study. Immunohistochemical analysis was performed on 452 archival tumors; univariate and multivariate analysis by the Cox's and logistic regression models was performed in all patients and in subgroups with [TP53(+)] and without TP53 accumulation [TP53(-)].

Results

The advantage of taxane-platinum therapy over platinum-based therapy was seen in the TP53(+), and not in the TP53(-) group. In the TP53(+) group taxane-platinum therapy enhanced the probability of complete remission (p = .018), platinum sensitivity (p = .014), platinum highly sensitive response (p = .038) and longer survival (OS, p = .008). Poor tumor differentiation diminished the advantage from taxane-platinum therapy in the TP53(+) group. In the TP53(-) group PC/PAC was at least equally efficient as taxane-platinum therapy and it enhanced the chance of platinum highly sensitive response (p = .010). However, in the TP53(-) group taxane-platinum therapy possibly diminished the risk of death in patients over 53 yrs (p = .077). Among factors that positively interacted with taxane-platinum therapy in some analyses were endometrioid and clear cell type, FIGO III stage, bulky residual tumor, more advanced age of patient and moderate tumor differentiation.

Conclusion

Our results suggest that taxane-platinum therapy is particularly justified in patients with TP53(+) tumors or older than 53 years. In the group of patients ≤53 yrs and with TP53(-) tumors platinum-based therapy is possibly equally efficient. We provide hints for planning randomized trials to verify these observations.

The clinical importance of Ki-67, p16, p14, and p57 expression in patients with advanced ovarian carcinoma

The present study addressed the impact of p14, p16, p57, and Ki-67 in a large cohort of uniformly treated patients with stage III ovarian cancer in relation to other clinicopathologic variables and prognosis. We immunohistochemically studied 171 primary tumors from previously untreated patients with advanced ovarian carcinomas for expression of Ki-67, p16, p14, and p57. High protein levels of Ki-67 (>10% positive nuclei) were found in 144 cases (84%), p16 (>50% positive nuclei) in 53 cases (31%), p57 (>10% positive nuclei) in 41 cases (24%), and p14 (any positive nuclei) in 19 cases (11%). A correlation between high Ki-67 expression and presence of residual disease after primary surgery (P = 0.019), ascites (P = 0.006), higher International Federation of Gynecology and Obstetrics substage (P < 0.001), poor differentiation (P < 0.001), and higher Silverberg histopathologic grade (P < 0.0001) was seen. High expression of p16 correlated to poor differentiation (P = 0.033) and higher Silverberg histopathologic grade (P = 0.018). In univariate analysis, high expression of Ki-67 (P = 0.0001) and p16 (P = 0.005) was associated with poor survival. However, in multivariate analysis, only high expression of Ki-67 was significantly associated with shorter survival (P = 0.025). No correlations were seen between expression of p14 and p57 and clinicopathologic parameters. None of the factors studied was able to predict response to chemotherapy. Our results showed that Ki-67 represents an independent prognostic predictor in stage III ovarian cancer. We did not find p16, p14, and p57 to be useful as prognostic markers.

Analysis of p53 protein expression levels on ovarian cancer tissue microarray using automated quantitative analysis elucidates prognostic patient subsets

BACKGROUND

p53 protein is regarded as a valuable prognostic marker in cancer with a potential use as a molecular target. Here, we sought to determine the prognostic value of p53 in ovarian cancer using a novel method of compartmentalized in situ protein analysis.

PATIENTS AND METHODS

A tissue array composed of 141 advanced stage ovarian cancers uniformly treated was constructed. For evaluation of p53 protein expression, we used an immunofluorescence-based method of automated in situ quantitative measurement of protein analysis (AQUA).

RESULTS

High nuclear p53 expression levels were associated with better outcome for overall survival (OS) (P = 0.0023) and disease-free survival (P = 0.0338) at 5-years. High cytoplasmic p53 expression levels were associated with better outcome for OS (P = 0.0002). In multivariable analysis, high nuclear and high cytoplasmic p53 level with International Federation of Gynecology and Obstetrics (FIGO) stage were the most significant predictor variables for OS and high nuclear p53 level with FIGO stage were the significant predictor variables for disease-free survival.

CONCLUSIONS

Assessment of the prognostic value of p53 protein levels using conventional immunohistochemistry is limited by the nonquantitative nature of the method. AQUA provides precise estimation of p53 protein levels and was able to elucidate the association of p53 protein levels and ovarian cancer prognosis.

The role of gene expression profiling in the clinical management of ovarian cancer

Several studies have addressed the clinical value of gene expression profiling in the field of ovarian cancer. This paper reviews the current status of knowledge that can be derived from such studies. Gene expression profiles can be used to reveal sets of genes that can distinguish normal ovarian tissue from invasive ovarian carcinomas. Independent validation of these sets may result in the identification of (a set of) markers valuable for the detection in an early stage. Microarray analysis has shown that different histological subtypes of ovarian cancer might be partly reflected by a different aetiology through the deregulation and activation of different pathways. In addition, this heterogeneity could therefore also lead to different tumour behaviours. Worldwide, the combination of paclitaxel and platinum chemotherapy has been incorporated in the standard protocol for the management of patients with advanced stage ovarian cancer, although the outcome in individual patients is uncertain. Gene expression profiling was found to be a prognostic tool with respect to chemosensitivity and had a predictive performance of 78-86%. With increasing numbers of data from published reports, access to these data for the reproducibility of its results and pooling becomes more and more important and will possibly lead to more individualisation of therapy.

Prognostic factors in ovarian carcinoma stage III patients. Can biomarkers improve the prediction of short- and long-term survivors?

The aim of the study was to determine if biomarker expression could help discriminate between short-term and long-term survivors in women with advanced ovarian cancer. Fifty-one patients with stage III ovarian cancer were selected for the study, which included 28 short-term survivors (death from ovarian cancer within 18 months) and 23 long-term survivors (alive for more than 5 years). There was no difference between the two groups with respect to FIGO substage, age, World Health Organization score, and first-line platinum therapy. Classic clinical pathologic parameters were examined together with p53, Bcl-2, Ki-67, PDGFRalpha, P-glycoprotein, BRCA1, and DNA ploidy. Immunohistochemistry was used for scoring biomarker expression and image cytometry for DNA ploidy. All patients had primary debulking surgery followed by first-line platinum therapy. On multivariate analysis, the presence of ascites, debulking surgery and repeat laparotomy, clear-cell histology, elevated CA125, and high Ki-67 score were all found to be of prognostic importance. The long-term survivors were characterized by primary optimal cytoreduction surgery (<1 cm residual disease), attempt at maximal tumor debulking by experienced gynecological oncologic surgeons, and the absence of ascites. Normal CA125 level before platinum therapy and negative Ki-67 expression also predicted a more favorable prognosis.

The prognostic impact of EphB2/B4 expression on patients with advanced ovarian carcinoma

OBJECTIVES

To analyze expressions of the EphB2 and EphB4 receptors in ovarian carcinomas and explore their clinicopathological correlations and prognostic value.

METHODS

115 patients with advanced ovarian carcinoma FIGO IIB to IV were involved. RT-PCR and immunohistochemistry were used to examine the expressions of EphB2/B4 receptor mRNA and protein. Correlations between protein expression and clinicopathological factors were also analyzed.

RESULTS

Ovarian carcinoma patients with age elder than 60 years had higher EphB2 expression than younger patients. Expression of EphB2 and EphB4 protein did not significantly correlate with any other clinical variables, including FIGO stage, residual tumor, histological type and differentiation grade. No significant correlation between mRNA and protein expression level for both of these receptors was seen. It was found that patients with strong immunostaining for EphB2 (P = 0.03) or EphB4 (P = 0.003) receptors had poorer survival, and patients with strong immunostaining for EphB4 receptor showed poorer response to chemotherapy (P = 0.036).

CONCLUSIONS

These studies suggest that EphB2 and B4 receptors are of prognostic value and EphB4 receptor may be an independent predictor of chemotherapy response in ovarian cancer patients.

Molecular Targeting of BCL2 and BCLXL Proteins by Synthetic BCL2 Homology 3 Domain Peptide Enhances the Efficacy of Chemotherapy

Chemotherapeutic agents are known to induce programmed cell death or apoptosis. The activation of cellular antiapoptotic defense that prevents the translation of drug-induced damage into cell death is the key factor in cellular antiapoptotic resistance that decreases the chemotherapeutic effectiveness of a broad spectrum of anticancer drugs. A novel proapoptotic anticancer drug delivery system (DDS) was designed to simultaneously induce apoptosis and suppress antiapoptotic cellular defense. The system includes three main components: 1) anticancer drug camptothecin (CPT) as an apoptosis inducer, 2) synthetic BCL2 homology 3 domain (BH3) peptide as a suppressor of cellular antiapoptotic defense, and 3) poly(ethylene glycol) (PEG) polymer as a carrier. The above DDS was studied in vitro using A2780 human ovarian carcinoma cells and in vivo on nude mice bearing xenografts of human ovarian tumor. The results obtained in both series of experiments corroborate each other. They show that the designed DDS provided intracellular delivery of active components and suppressed cellular antiapoptotic defense, leading to the more pronounced induction of caspase-dependent signaling pathway of apoptosis compared with CPT alone and simple CPT-PEG conjugate. Including BH3 peptide in complex DDS decreased apoptotic cellular defense, substantially increased toxicity of the whole complex, and provided high antitumor activity. Therefore, the proposed novel multicomponent proapoptotic anticancer drug delivery system has high potential to enhance the efficacy of chemotherapy.

Mutational spectrum of p53 mutations in primary breast and ovarian tumors

Breast and ovarian cancers, like other cancers, occur due to genetic damage. Research aimed to determine the specific genes involved in the development of breast and ovarian cancers will help to understand how normal breast and ovarian epithelial cells escape regulation of proliferation, apoptosis and senescence. It was determined that approximately 10% of ovarian cancers and 20-30% of breast cancers arise in women who have inherited mutations in cancer susceptibility genes such as BRCA1, BRCA2 and other DNA repair genes. The ability to perform genetic testing permits the identification of women at increased risk who can then be offered preventive strategies. The vast majority of ovarian and breast cancers are sporadic, presumably resulting from the accumulation of genetic damage over lifetime. Several genes involved in breast and ovarian carcinogenesis have been identified, most notably the p53 tumor suppressor. The recent availability of expression microarrays has facilitated the simultaneous screening of thousands of genes and this will extend further the understanding of molecular events involved in the dynamic development of ovarian and breast cancers. Then, all this knowledge could be translated into effective screening, surveillance, prevention, and treatment strategies in the future.

Expression of Bcl-xL in ovarian carcinoma is associated with chemoresistance and recurrent disease

OBJECTIVE

The long-term survival of patients with epithelial ovarian cancer is limited by the emergence of tumor cells that are resistant to chemotherapy. We hypothesized that expression of Bcl-x(L), a homologue of Bcl-2 that confers protection from chemotherapy-induced apoptosis, may be predictive of patients' clinical response to treatment, and that treatment with chemotherapy may result in the selection of tumor cells that overexpress this protein.

METHODS

We determined the expression of Bcl-x(L) in epithelial ovarian cancers from 28 patients at the time of initial staging laparotomy and in recurrent tumors in the same patients following treatment with platinum-based chemotherapy. The data were analyzed to determine whether Bcl-x(L) expression was predictive of clinical outcome. A2780 ovarian cancer cells were stably transfected with Bcl-x(L) or control plasmid. Chemotherapy-induced apoptosis in these cell lines was determined in vitro and in a xenograft model.

RESULTS

Bcl-x(L) expression in primary tumors was associated with a significantly shorter disease-free interval as compared to patients whose tumors did not express Bcl-x(L) (1.6 months as compared to 7.7 months). We found that Bcl-x(L) expression conferred resistance to chemotherapy-induced apoptosis resulting from treatment with cisplatin, paclitaxel, topotecan, and gemcitabine in vitro. In a xenograft model, Bcl-x(L) expressing tumors continued to grow following treatment with cisplatin, paclitaxel, topotecan, and gemcitabine, in contrast to control tumors, which disappeared.

CONCLUSION

These results portray an important role for Bcl-x(L) as a key factor associated with chemotherapy failure in the treatment of ovarian cancer.

Sequential single agents as first-line chemotherapy for ovarian cancer: a strategy derived from the results of GOG-132

First-line chemotherapy for ovarian cancer during the past decade has evolved toward the use of carboplatin and paclitaxel combinations. This has been based on randomized trials showing that combinations of these two drugs lead to a outcome similar to that obtained using cisplatin and paclitaxel (that had, in turn, proven superior in progression-free survival and overall survival to cisplatin and cyclophosphamide) but with less toxicity. Surprisingly, taxane-platinum combinations were not superior to control arms in two studies (ICON3 and GOG-132) utilizing carboplatin or cisplatin as the comparators. This has renewed interest in the role of single agents in first-line chemotherapy - a concept also supported by a number of prior clinical trials with single-agent platinum compounds yielding results not inferior to combinations. Early 'pre-emptive' crossover (prior to the stipulated clinical progression) to paclitaxel or a paclitaxel-containing regimen, however, occurred in 24% of patients initially treated with cisplatin on GOG-132. This has led to the interpretation of this trial as a combination versus sequential design. Although not subscribing to this interpretation, the results of GOG-132 and ICON3 not only raise doubts over a clear superiority of combinations over single agents but also lead to a consideration of sequential treatment designs for first line. Advantages of such designs are: (a) ability to provide 'dose-dense' platinums followed by 'dose-dense' paclitaxel and, perhaps, other drugs; and (b) the potential of acquiring biological data linked to the antitumor effects of a specific drug. Mathematical modeling and recent positive results in breast cancer adjuvant therapy support the use of 'dose-dense' strategies, and these should be considered in the design of future trials in ovarian cancer.

Alteration of cell cycle regulators correlates with survival in epithelial ovarian cancer patients1 1Authors Hashiguchi and Tsuda contributed equally to this article

The p16-cyclinD1/CDK4-pRb pathway (RB pathway) and p14ARF-MDM2-p53 pathway (p53 pathway) work at the G1-S checkpoint, and the ATM-chk2-CDC25-cyclinB1/cdk1 pathway works at the G2-M checkpoint. The disruption of these pathways is thought to be related to the prognosis of human cancer. In this study, we analyzed the status of these pathways in 107 epithelial ovarian cancer (EOC) patients by immunohistochemistry and evaluated the relationship of these results with chemotherapy response and the prognosis. Altered RB, p53, and G2 pathways were detected in 50.5% (54/107), 51.4% (55/107), and 33.6% (36/107) of cases, respectively. The overall survival (OS) of 77.3% for patients with a normal RB pathway was significantly higher than the OS of 50.0% for patients with an altered RB pathway (by Kaplan-Meier analysis, P = 0.0021). The OS of 66.2% for patients with a normal G2 pathway was significantly higher than the OS of 58.3% for patients with an altered G2 pathway (P = 0.0416). However, the status of the p53 pathway was not related to OS. By univariate and multivariate analyses, advanced stage, high histological grade, altered RB pathway, and altered G2 pathway were significant predictors of poor OS. However, there was no significant relationship between pathway status and chemotherapy response. The status of the RB pathway and of the G2 pathway were independent prognostic factors of EOC.

Distinct subtypes of serous ovarian carcinoma identified by p53 determination☆☆☆☆☆Supplementary data associated with this article can be found at doi: 10.1016/S0090-8258(03)00608-5

OBJECTIVE

The overall prognosis of ovarian carcinoma is poor. However, the outcome of apparently similar cases is highly variable, and molecular markers that would predict disease outcome in a clinically useful manner are lacking. We investigated the value of p53 expression as a disease determinant in serous carcinoma, which is the most common type of ovarian carcinoma and has shown the highest frequency of p53 alterations.

METHODS

Tissue microarray constructed of 522 serous ovarian carcinomas was examined immunohistochemically using DO-7 monoclonal antibody against p53 protein. The findings were correlated with overall and disease-free survival, response to therapy, and clinicopathological characteristics of the patients.

RESULTS

Both excessive and completely negative p53 staining confered poor patient outcome and were considered aberrant p53 expression. Patients with aberrant p53 (59% of the carcinomas) showed 5-year overall survival of 26% (20-31%), whereas patients with normal p53 expression (41% of the carcinomas) showed 5-year overall survival of 79% (95% CI, 74-85%) (P < 0.0001). The association of aberrant p53 with poor prognosis was independent of clinicopathological parameters, e.g., stage and grade. In addition, aberrant p53 status was significantly associated with shorter disease-free survival (P < 0.0001) and poor response to therapy (P < 0.0001). In the most common subgroups, stage III and stage I carcinomas, 5-year overall survival rates for patients showing normal p53 vs. aberrant p53 were 72% vs. 19% (P < 0.0001) and 99% vs. 56% (P < 0.0001), respectively.

CONCLUSION

P53 expression status divides serous ovarian carcinomas into two distinct subtypes: one with a relatively good prognosis and the other with a particularly poor outcome.

Evaluation of clinical significance of TP53, BCL-2, BAX and MEK1 expression in 229 ovarian carcinomas treated with platinum-based regimen

In cell line studies, BCL-2, BAX, as well as novel MEK1 protein levels have strong influence on ovarian cancer response to cisplatin-based chemotherapy. However, such associations have not been demonstrated clinically. We evaluated prognostic/predictive significance of these proteins with regard to TP53 status. Immunohistochemical analysis was performed on 229 ovarian carcinomas FIGO stage IIB-IV treated with platinum-based chemotherapy; the results were analysed by the Cox and logistic regression models. Clinical parameters (residual tumour size, patient age, FIGO stage) were the only indicators of overall survival (OS) and the strongest predictors of complete remission (CR). On the other hand, BAX expression was the strongest (P=0.005) or the only (in FIGO IIIC, P=0.02) prognostic indicator of disease-free survival (DFS) in the TP53(+) group. TP53(+) and TP53(-) ovarian carcinomas differed in clinical and molecular prognostic and predictive factors. Another novel finding is that CR was negatively influenced by high BAX expression in all patients group (P=0.047) and by BCL2 expression in the TP53(-) group (P=0.05). High MEK1 expression was associated with endometrioid and clear cell carcinomas (P=0.049); its loss was found with advancing FIGO stage (P=0.002). Our results suggest that binomial TP53 status divides ovarian carcinomas into two biologically distinct groups. BAX expression is an important factor of DFS in the TP53(+) group. BCL-2 and BAX, but not MEK1 expressions have predictive value in ovarian cancer patients treated with platinum-based chemotherapy.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

P53 and Bcl-2 as prognostic predictors in epithelial ovarian cancer

The study was designed to evaluate the prognostic importance of clinical and pathologic variables with p53 and Bcl-2 in epithelial ovarian cancer using multivariate analysis. Tumor tissues from 90 patients were analyzed immunohistochemically for p53 and Bcl-2 expression. Hazard ratios were calculated in univariate and multivariate survival analyses. Forty-two (47%) were considered positive for p53 expression and 18 (20%) were positive for Bcl-2. Positive expression for p53 was less frequent in patients in FIGO stage I (22%). Positive staining for Bcl-2 correlated significantly with the histologic type (P < 0.01). No direct correlations could be demonstrated between p53 and Bcl-2 expression and age or histologic grade. In univariate analysis, p53 and Bcl-2 expression were not significantly correlated with overall survival, disease-free survival, or progression time. FIGO stage III and IV and residual disease > or =2 cm3 after first surgery were significantly correlated with poor outcome in univariate analysis. FIGO stage retained their independent prognostic value in multivariate analysis. Neither p53 nor Bcl-2 had any significant influence on outcome in multivariate survival analysis. FIGO stage proved to be the only significant independent prognostic factor in epithelial ovarian cancer, although residual disease remains correlated with disease-free survival.

Correlation of p53 immunostaining in primary and residual ovarian cancer at the time of positive second-look laparotomy and its prognostic role: a Southwest Oncology Group ancillary study

OBJECTIVE

The objective of this study was to verify the correlation between p53 immunostaining at initial diagnosis and at positive reassessment after completing platinum-based chemotherapy and to assess prognostic differences between patients whose tumors display positive immunostaining versus those that have negative immunostaining at such reassessment.

METHODS

This study made use of samples from patients entered into a prospective randomized study of the Southwest Oncology Group (SWOG 8835) that treated patients with minimal residual disease at second-look laparotomy with either intraperitoneal (ip) mitoxantrone or fluorodeoxyuridine (FUDR). Unstained slides from tumor obtained at the initial diagnosis and at reassessment were retrospectively requested from individual institutions. The degree of nuclear staining was determined using the anti-p53 mouse monoclonal antibody Pab1801 and previously published techniques, with a cutoff of 10% or more staining of tumor cell nuclei for a positive result. Cox model regression analysis was performed for overall survival and progression-free survival, with p53 status, ip treatment, and baseline CA125 as independent variables.

RESULTS

p53 determination was feasible in 22 patients both at diagnosis and at the second-look samples; 9 additional patients had only either sample available. Since concordance between the 10 negative and 12 positive immunostained samples was 100%, all 31 patients were considered in the Cox model. The death hazard ratio of p53-positive versus p53-negative patients was 4.18 (two-sided P value of 0.006).

CONCLUSION

p53 immunostaining at second-look laparotomy correlates with the immunostaining at diagnosis. In this series confined to patients with minimal residual disease after initial therapy subjected to second-line intraperitoneal treatment, it appears to identify a poor prognostic (positive) subset for survival.

The prognostic importance of p53, bcl-2, and bax in early stage epithelial ovarian carcinoma treated with adjuvant chemotherapy

Epithelial ovarian cancer is one of the major causes of death among women. The increasing knowledge about molecular events involved in the early stages of ovarian tumorigenesis may provide the basis for management in the future. In a series of 109 patients with epithelial carcinomas in FIGO stages IA-IIC, a number of clinicopathologic prognostic factors (age, FIGO stage, histopathologic type, and tumor grade) were studied in relation to the biologic factors p53, bcl-2, and bax, which are important regulators of apoptosis. Immunohistochemical techniques were used. All the patients received adjuvant chemotherapy after the primary surgery. Univariate analysis showed that expression of p53 was significantly associated with tumor grade (P = 0.014), probability of persistent disease (P = 0.016), and cancer-specific survival rate (P = 0.007). Positive bcl-2 staining was associated with endometrioid tumor subtype (P = 0.029) and a favorable tumor grade distribution (P = 0.034), but not with the survival status. The combined p53-bcl-2 expression was related to histopathologic subtype (P = 0.032), tumor grade (P = 0.011), persistent disease (P = 0.014), and risk of dying due to the disease (P = 0.039). The bax status was not a prognostic factor, but the combined p53-bax expression showed an association with FIGO stage (P = 0.014), tumor grade (P = 0.034), persistent disease (P = 0.006), and risk of dying due to the disease (P = 0.039). The combined bcl-2-bax expression was related to histopathologic subtype (P = 0.045) and tumor grade (P = 0.022). In a multivariate Cox analysis, tumor grade (P = 0.014), and p53 status (P = 0.020) were independent and significant prognostic factors with regard to the cancer-specific survival rate.

Loss of MDM2 expression in human head and neck squamous cell carcinomas and clinical significance

The transforming potential of the MDM2 oncogene has been attributed to the overproduction of the protein. In order to investigate regulation of MDM2 expression in head and neck squamous cell carcinomas, we analysed MDM2 gene amplification, and mRNA and protein expression in tumour specimens from 62 patients, in cell lines, and in normal epithelium adjacent to tumours or obtained from healthy patients. Additionally, TP53-induced MDM2-P2 transcription was evaluated and compared with TP53 status. MDM2 gene amplification and mRNA over-expression is infrequent, 7 and 9%, respectively. The predominant transcript codes for full-length MDM2 protein (90kD) and the level of alternatively spliced forms is not significant. We show that only 47% of tumours exhibit MDM2 immunostaining in more than one third of the neoplastic cells, and thus more than half of the tumours display no or low levels of MDM2 protein. In contrast, MDM2 protein is always detectable in basal and parabasal cells of morphologically normal epithelium outside the invasively growing tumour, as well as in a normal uvula sample. Similarly, the total amount of MDM2 transcripts analysed by reverse transcriptase-polymerase chain reaction is reduced in tumour samples compared to normal tissues, essentially due to a decrease in P2 transcript levels. The relationship between mutated p53 status and low levels of MDM2 found in cell lines is also observed to a certain extent in primary tumour samples. Overall, there is a high frequency of TP53 mutation and under-expression of MDM2 in the head and neck tumours. Moreover, a significant association of decreased MDM2 expression is observed with advanced tumour stage and 3 years survival.