p53, c-erbB2, and PCNA status in benign, proliferative and malignant ovarian surface epithelial neoplasms: a study of 75 cases

Expression of p53 and HER2/Neu in Kenyan Women With Primary Ovarian Carcinoma

Ovarian carcinomas are a leading cause of cancer mortality among women. Two of the more commonly described markers of prognostic significance in primary ovarian carcinomas are p53 and HER2/neu. Overexpression of both markers is associated with poor prognosis. This study aimed to determine the frequency and pattern of p53 and HER2/neu expression in primary ovarian carcinomas in Kenyan women and to describe the clinical and pathologic features of ovarian carcinomas diagnosed at 3 different hospitals in Kenya. Primary ovarian carcinomas diagnosed at the Departments of Pathology at Aga Khan University Hospital, Nairobi; the Aga Khan Hospital, Kisumu; and the AIC Kijabe Hospital in Kenya over a period of 3 years from January 2009 to December 2011 were recorded. Sixty-seven ovarian carcinomas were identified and blocks retrieved from archives. Hematoxylin-eosin-stained slides of these were reviewed and appropriate sections were stained for p53 and HER2/neu using standard immunohistochemical techniques. The primary outcome was presence and intensity of staining for p53 and HER2/neu. The most frequent malignancy was serous carcinoma. A total of 43.3% (95% confidence interval, 32.1%-55.2%) of carcinomas were positive for p53, and 13.4% (95% confidence interval, 7.2%-23.6%) were positive for HER2/neu. Serous carcinoma and adenocarcinoma, not otherwise specified were more likely to be positive for p53. There was no association noted between the histologic grade or pathologic stage and positivity for either p53 or HER2/neu. The expression of p53 and HER2/neu in primary ovarian carcinomas in Kenyan women is not different from that described in the literature.

Prognostic value and clinicopathological significance of p53 and PTEN in epithelial ovarian cancers

OBJECTIVE

The aim of the study was to evaluate the prognostic significance of p53 and PTEN in patients with epithelial ovarian cancer who were treated with taxane and platinum-based chemotherapy.

METHODS

Retrospectively collected paraffin blocks from 151 epithelial ovarian cancer patients treated with debulking surgery followed by taxane and platinum chemotherapy were analyzed. Expression of p53 and PTEN was assessed by immunohistochemistry. The staining pattern was correlated with clinicopathological variables.

RESULTS

Overexpression of p53 was found in 80 of the 151 cases (53.0%), and it was related to stage, histology and grade. Reduced expression of PTEN was found in 104 of the 151 cases (68.9%), and it was not related to any clinicopathological factors other than age. In survival analysis, stage (p=0.001), residual tumor (p=0.045), lymph node metastases (p=0.012), and PTEN expression (p=0.009) were significant predictors for disease-free survival (DFS). The median DFS of patients with reduced PTEN expression was 20 months (range, 3-71 months), whereas that of patients with normal PTEN expression was 53 months (range, 2-81 months).

CONCLUSIONS

Reduced PTEN expression is a poor prognostic factor for DFS in patients with epithelial ovarian cancer who were treated with debulking surgery and postoperative taxane and platinum chemotherapy.

Clinical implications of the ErbB/epidermal growth factor (EGF) receptor family and its ligands in ovarian cancer

The ERBB or EGF receptor (EGFR) proto-oncogene family, which consists of four structurally-related transmembrane receptors (i.e., EGFR, ErbB2, ErbB3, and ErbB4), plays an etiological role in the molecular pathogenesis of cancer and is a key therapeutic target in many types of cancer, including ovarian cancer. These ErbB/EGF receptor tyrosine kinases play important physiologic roles in cell proliferation, survival, adhesion, motility, invasion, and angiogenesis. It is, therefore, not surprising that gene amplification, genetic mutation, and altered transcription/translation result in aberrant ErbB/EGF receptor expression and/or signal transduction, contributing to the development of malignant transformation. Clinically, the diagnostic, prognostic, and theragnostic significance of any single ErbB receptor and/or ErbB ligand is controversial, but generally, ErbB receptor overexpression has been correlated with poor prognosis and decreased therapeutic responsiveness in ovarian cancer patients. Thus, anticancer agents targeting ErbB/EGF receptors hold great promise for personalized cancer treatment. Yet, challenges remain in designing prospective clinical trials to assess the clinical utility of ErbB receptors and their ligands to diagnose cancer; to predict progression-free and overall survival, therapeutic responsiveness, and disease recurrence; and to monitor treatment responsiveness. Here, we review the tissue expression and serum biomarker studies that have evaluated the diagnostic, prognostic, and theragnostic utility of ErbB/EGF receptors, their circulating soluble isoforms (sEGFR/sErbBs), and their cognate ligands in ovarian cancer patients.

The prognostic value of PTEN, p53, and beta-catenin in endometrial carcinoma: a prospective immunocytochemical study

Mutations of the PTEN, p53, and beta-catenin genes are the most frequent molecular defects in endometrial carcinomas. The aim of this study was to investigate their prognostic significance in this form of cancer. Imprint smears were obtained from 80 fresh endometrial tumor specimens and studied immunocytochemically for the expression of PTEN, p53, and beta-catenin proteins. The staining pattern was correlated with several well-established prognostic parameters, including 5-year survival. Positive staining of p53 was significantly correlated with increased stage (P < 0.0001), lymph node metastases (P = 0.001), and a nonendometrioid histology (P = 0.001). On the contrary, positive beta-catenin expression was significantly associated with decreased stage (P = 0.002), decreased grade (P = 0.007), and a negative lymph node status (P = 0.023). PTEN positivity was correlated with decreased stage (P = 0.002) and negative lymph nodes (P = 0.008). All the three markers affected survival significantly in univariate analysis but only beta-catenin had an independent prognostic impact. An independent prognostic significance was also shown for PTEN in the stage I subgroup of patients. The results of our study indicate that loss of beta-catenin expression is a strong and independent predictor of an unfavorable outcome in patients with endometrial carcinoma. Loss of PTEN may also be associated with a worse prognosis in patients with early-stage disease.

Molecular targets in gynaecological cancers

The application of high throughput expression profiling and other advanced molecular biology laboratory techniques has revolutionised the management of cancers and is gaining attention in the field of gynaecological cancers. Such new approaches may help to improve our understanding of carcinogenesis and facilitate screening and early detection of gynaecological cancers and their precursors. Individualised prediction of patients' responses to therapy and design of personalised molecular targeted therapy is also possible. The studies of various molecular targets involved in the various signal pathways related to carcinogenesis are particularly relevant to such applications. At the moment, the application of detection and genotyping of human papillomavirus in management of cervical cancer is one of the most well established appliances of molecular targets in gynaecological cancers. Methylation, telomerase and clonality studies are also potentially useful, especially in assisting diagnosis of difficult clinical scenarios. This post-genomic era of clinical medicine will continue to make a significant impact in routine pathology practice. The contribution of pathologists is indispensable in analysis involving tissue microarray. On the other hand, both pathologists and bedside clinicians should be aware of the limitation of these molecular targets. Interpretation must be integrated with clinical and histopathological context to avoid misleading judgement. The importance of quality assurance of all such molecular techniques and their ethical implications cannot be over-emphasised.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Tissue microarray analysis of EGFR and erbB2 copy number changes in ovarian tumors

The objective of this study was to assess the implication of copy number changes of epidermal growth factor receptor (EGFR) and erbB2 genes in the etiology and progression of ovarian tumors. In our study, we used the highly reliable method of fluorescent in situ hybridization, applied on tissue microarray, containing 1006 ovarian tumors from different malignancy, histologic type and grade, and tumor stage, in order to analyze the correlations between gene copy number changes and tumor phenotype. We established copy number changes of erbB2 in 15.30% of malignant ovarian tumors-8.16% amplifications and 7.14% gains. The frequency of EGFR copy number changes was 10.67%-3.65% amplifications and 7.02% gains. EGFR gains occurred with approximately the same frequency in malignant (7.02%), low malignant potential (8.33%), and benign (7.19%) ovarian tumors. ErbB2 amplification was associated with clear cell type of ovarian cancer (P < 0.04). No amplification of EGFR and erbB2 genes was established in tumors with low malignant potency and in benign tumors. Regarding cancer phenotype, there was no statistically significant association between erbB2 copy number changes and histologic grade as well as tumor stage of ovarian cancer. EGFR gains are early events in ovarian tumorigenesis. Our results showed similar frequencies of EGFR gains in different grade tumors, while EGFR amplification increased from grades 1 to 2 to 3.

Prognostic, predictive and therapeutic implications of HER2 in invasive epithelial ovarian cancer

The HER2 oncogene encodes a transmembrane protein partially homologous to epidermal growth factor receptor. This oncogene has been studied mainly in breast cancer where it has prognostic, predictive and therapeutic target value. The expression of HER2 in epithelial ovarian cancer has been less studied. HER2 expression can be determined through IHC, FISH, CISH and ELISA among other tests, with reported positivity frequencies of overexpression varying from 1.8% to 76%. In some studies HER2 overexpression has been associated with advanced stages, poorly differentiated tumors, resistance to chemotherapy and shortened survival. Although trastuzumab is able to produce a low response rate as a single agent in pretreated ovarian cancer patients with overexpression of HER2, its usefulness is limited due to the low frequency of strong expression. To date there is not enough bases for assessment and HER2-based therapies in epithelial ovarian cancer.

Diagnostic approach using the expression profiling of the P53 tumor suppressor gene and its related proteins in ovarian epithelial tumors

The initial aim of this study was to examine the expression profiles of P53 and its upstream genes, downstream genes, and cell cycle regulators to determine whether these markers are useful for making a differential diagnosis among the benign, borderline, and malignant ovarian epithelial tumors. Between borderline and malignant tumors, the increased expression levels of P53, Bax, Cyclin E, and cyclin-dependent kinase-2 as well as the decreased expression levels of growth arrest and DNA damage (GADD45) and murine double minute-2 (MDM2) were significantly associated with malignancy (P < 0.01, each). Using the receiver operating curve (ROC), the most reliable cutoff value of the added-up staining scores of those markers was 4.5 with 79% sensitivity and 89% specificity for malignancy. Between benign and borderline tumors, the P21 and Bax expression levels were significantly higher in borderline tumors, whereas the Bcl-2 expression level was much higher in benign tumors (P < 0.01, each). Using the ROC, the cutoff value of the added-up staining scores used to discriminate between the two groups was 2.5 with 70% sensitivity and 74% specificity for borderline tumors. Thus, for the differential diagnosis between borderline and malignant tumors, the cutoff value 4.5 of the cumulative staining scores can be used. However, the cutoff value 2.5 for discrimination between benign and borderline tumors may not be useful because of its relatively low sensitivity and specificity. In addition, the P53, GADD45, Cyclin E, and MDM2 expression levels in malignant ovarian tumors might be useful for determining the histologic grade and type.

Prognostic significance of p53, Her-2, and EGFR overexpression in borderline and epithelial ovarian cancer

The objective of the study was to evaluate the prognostic effect of p53, Her-2, and EGFR in borderline and epithelial ovarian cancer. Tumor tissue from 85 patients with borderline and 783 patients with epithelial ovarian cancer stage I-IV were analyzed immunohistochemically for p53 positivity and over-expression of Her-2 and EGFR. In the ovarian cancer (OC) group 415 patients (53%) had p53-positive tumors, 272 (35%) had tumors with Her-2 over-expression, and 483 (62%) had over-expression of EGFR. In the OC group the classical prognostic factors (older age, higher FIGO stage, and poorer differentiated stage) had significant prognostic value in both uni- and multivariate analyses. Multivariate analyses in the OC group proved p53 positivity to increase mortality significantly depending on the grade of the tumor. Her-2 likewise increased the risk of mortality significantly in this group depending on the grade of the tumor. EGFR on the other hand did not have any additional prognostic effect in the OC group after adjustment for the classical prognostic and molecular factors was made. In the borderline group Her-2 and EGFR over-expression in combination, adjusted for age and p53, significantly improved the prognosis.

Surface charge and hydrophobicity determine ErbB2 binding to the Hsp90 chaperone complex

The molecular chaperone Hsp90 modulates the function of specific cell signaling proteins. Although targeting Hsp90 with the antibiotic inhibitor geldanamycin (GA) may be a promising approach for cancer treatment, little is known about the determinants of Hsp90 interaction with its client proteins. Here we identify a loop within the N lobe of the kinase domain of ErbB2 that determines Hsp90 binding. The amino acid sequence of the loop determines the electrostatic and hydrophobic character of the protein's surface, which in turn govern interaction with Hsp90. A point mutation within the loop that alters ErbB2 surface properties disrupts Hsp90 association and confers GA resistance. Notably, the immature ErbB2 point mutant remains sensitive to GA, suggesting that mature and nascent client kinases may use distinct motifs to interact with the Hsp90 chaperone complex.

Location of inclusion cysts in mouse ovaries in relation to age, pregnancy, and total ovulation number: implications for ovarian cancer?

Benign ovarian cysts are thought to be precursor lesions that differentiate and transform into carcinoma. With the aim of testing the hypothesis that increased ovulation number increases the frequency or number of ovarian cysts, the development and appearance of ovarian cysts was investigated in mice of differing ages and total lifetime ovulation number. High total ovulation number was induced by keeping mice in cages divided by a screen, with a male on one side and two females on the other side. Significantly more cysts were observed in animals subjected to incessant ovulation for 8 months and in 12 month breeding mice than in 3-month virgin mice or 1-month prepubertal animals. These cysts had the appearance of benign serous inclusion cysts. When cystic ovaries were serial sectioned, 47% of cysts had a connection to the ovarian hilus and potentially to the tubules of the rete ovarii, 31% were adjacent to the hilus, and 22% had an intra-ovarian location. A significant increase in intra-ovarian cysts was observed in the 8-month incessant ovulation group, implying that high ovulation number leads to ovarian surface invagination and inclusion cyst formation. In conclusion, ovarian inclusion cysts may be derived from more than one epithelial source, but incessant ovulation may increase the proportion derived from the ovarian surface epithelium. Because the cysts observed resembled human serous inclusion cysts these results have possible implications for epithelial ovarian carcinoma.

Rates of topoisomerase II-alpha and HER-2 gene amplification and expression in epithelial ovarian carcinoma

OBJECTIVES

Topoisomerase II-alpha (T2a) is being actively investigated as a potential predictive marker of response to anthracyclines in breast cancer (BC). Although the role of T2a inhibitors as upfront and salvage treatment for epithelial ovarian carcinoma (EOC) remains unclear, we speculated that a small subgroup of ovarian cancer patients could derive a selective benefit from these agents. In this study, we investigated the actual rates of T2a and HER-2 amplification and overexpression by fluorescence in situ hybridisation (FISH) and immunohistochemistry (IHC), respectively.

METHODS

Seventy-three samples of chemotherapy-naive patients with EOC were selected from our archives. FIGO stage and histology were available for most patients.

RESULTS

Based on arbitrary cut-offs of > or =1.5 and > or =2 (ratio copies/centromere17), amplification rates for HER-2 were 15/64 (23.4%) and 8/64 (12.5%) versus 16/64 (25%) and 5/64 (7.8%) for T2a. We found only 3/72 (4.2%) cases of HER-2 overexpression (3+) versus 15/70 (21.4%) for T2a (staining of >10% of the cells). There was a modest correlation between T2a amplification and overexpression (P=0.01) and a strong correlation between T2a and HER-2 amplification when these markers were analysed as continuous variables (P<0.001). T2a amplification significantly correlated with advanced FIGO stage (P=0.02).

CONCLUSION

The assessment of HER-2 and T2a amplification and overexpression by FISH and IHC, respectively, is feasible in EOC. These tests can be used for large-scale evaluation of the potential predictive and prognostic value of these markers in the future. Further studies with a special focus on T2a are needed to determine the best cut-offs for potential clinical use in the future.

HER-2/neu-specific monoclonal antibodies collaborate with HER-2/neu-targeted granulocyte macrophage colony-stimulating factor secreting whole cell vaccination to augment CD8+ T cell effector function and tumor-free survival in Her-2/neu-transgenic mice

HER-2/neu is overexpressed in several cancers including 30% of breast carcinomas, and correlates with a poor outcome. HER-2/neu-transgenic (neu-N) mice that overexpress the non-transforming rat neu develop spontaneous mammary carcinomas and demonstrate immunotolerance to the neu protein similar to that observed in patients with neu-expressing cancers. In neu-N mice, neu-targeted vaccination induces weak T cell and negligible Ab responses sufficient to delay but not eradicate transplanted neu-expressing tumor. Here we demonstrate that passive infusion of neu-specific mAbs in sequence with whole cell vaccination significantly improves tumor-free survival over either modality alone. Importantly, treatment of neu-N mice with vaccine in combination with two distinct neu-specific Abs is particularly efficacious, preventing tumor in 70% and eradicating established tumor in 30% of neu-N mice. In vivo lymphocyte subpopulation depletion experiments demonstrate that the efficacy of Ab, alone or combined with vaccine, is dependent on both CD4(+) and CD8(+) T cells. Furthermore, the in vivo antitumor effects of vaccine and Ab are associated with a significant increase in the number and function of neu-specific CD8(+) T cells. Collectively, these observations suggest that similarly increased efficacy could be obtained by combining neu-targeted vaccination and neu-specific Abs such as trastuzumab (Herceptin) in patients with neu-expressing cancers.

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.

Increased p53 mutation load in nontumorous human liver of wilson disease and hemochromatosis: oxyradical overload diseases

Hemochromatosis and Wilson disease (WD), characterized by the excess hepatic deposition of iron and copper, respectively, produce oxidative stress and increase the risk of liver cancer. Because the frequency of p53 mutated alleles in nontumorous human tissue may be a biomarker of oxyradical damage and identify individuals at increased cancer risk, we have determined the frequency of p53 mutated alleles in nontumorous liver tissue from WD and hemochromatosis patients. When compared with the liver samples from normal controls, higher frequencies of G:C to T:A transversions at codon 249 (P < 0.001) and C:G to A:T transversions and C:G to T:A transitions at codon 250 (P < 0.001 and P < 0.005) were found in liver tissue from WD cases, and a higher frequency of G:C to T:A transversions at codon 249 (P < 0.05) also was found in liver tissue from hemochromatosis cases. Sixty percent of the WD and 28% of hemochromatosis cases also showed a higher expression of inducible nitric oxide synthase in the liver, which suggests nitric oxide as a source of increased oxidative stress. A high level of etheno-DNA adducts, formed from oxyradical-induced lipid peroxidation, in liver from WD and hemochromatosis patients has been reported previously. Therefore, we exposed a wild-type p53 TK-6 lymphoblastoid cell line to 4-hydroxynonenal, an unsaturated aldehyde involved in lipid peroxidation, and observed an increase in G to T transversions at p53 codon 249 (AGG to AGT). These results are consistent with the hypothesis that the generation of oxygen/nitrogen species and unsaturated aldehydes from iron and copper overload in hemochromatosis and WD causes mutations in the p53 tumor suppressor gene.