Genetic alterations in ovarian carcinoma: with specific reference to histological subtypes

Prediction of Chemoresistance-How Preclinical Data Could Help to Modify Therapeutic Strategy in High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) is one of the most lethal tumors generally and the most fatal cancer of the female genital tract. The approved standard therapy consists of surgical cytoreduction and platinum/taxane-based chemotherapy, and of targeted therapy in selected patients. The main therapeutic problem is chemoresistance of recurrent and metastatic HGSOC tumors which results in low survival in the group of FIGO III/IV. Therefore, the prediction and monitoring of chemoresistance seems to be of utmost importance for the improvement of HGSOC management. This type of cancer has genetic heterogeneity with several subtypes being characterized by diverse gene signatures and disturbed peculiar epigenetic regulation. HGSOC develops and metastasizes preferentially in the specific intraperitoneal environment composed mainly of fibroblasts, adipocytes, and immune cells. Different HGSOC subtypes could be sensitive to distinct sets of drugs. Moreover, primary, metastatic, and recurrent tumors are characterized by an individual biology, and thus diverse drug responsibility. Without a precise identification of the tumor and its microenvironment, effective treatment seems to be elusive. This paper reviews tumor-derived genomic, mutational, cellular, and epigenetic biomarkers of HGSOC drug resistance, as well as tumor microenvironment-derived biomarkers of chemoresistance, and discusses their possible use in the novel complex approach to ovarian cancer therapy and monitoring.

A Practical Nomogram to Predict Early Death in Advanced Epithelial Ovarian Cancer

Background: Ovarian cancer is a common gynecological malignancy, most of which is epithelial ovarian cancer (EOC). Advanced EOC is linked with a higher incidence of premature death. To date, no effective prognostic tools are available to evaluate the possibility of early death in patients with advanced EOC.

Methods: Advanced (FIGO stage III and IV) EOC patients who were enrolled in the Surveillance, Epidemiology, and End Results database between 2004 and 2015 were regarded as subjects and studied. We aimed to construct a nomogram that can deliver early death prognosis in patients with advanced EOC by identifying crucial independent factors using univariate and multivariate logistic regression analyses to help deliver accurate prognoses.

Results: In total, 13,403 patients with advanced EOC were included in this study. Three hundred ninety-seven out of a total of 9,379 FIGO stage III patients died early. There were 4,024 patients with FIGO stage IV, 414 of whom died early. Nomograms based on independent prognostic factors have the satisfactory predictive capability and clinical pragmatism. The internal validation feature of the nomogram demonstrated a high level of accuracy of the predicted death.

Conclusions: By analyzing data from a large cohort, a clinically convenient nomogram was established to predict premature death in advanced EOC. This tool can aid clinicians in screening patients who are at higher risk for tailoring treatment plans.

Development of a 3D functional assay and identification of biomarkers, predictive for response of high-grade serous ovarian cancer (HGSOC) patients to poly-ADP ribose polymerase inhibitors (PARPis): targeted therapy

Background

Poly(ADP-ribose) polymerase inhibitors (PARPis) specifically target homologous recombination deficiency (HRD) cells and display good therapeutic effect in women with advanced-stage BRCA1/2-mutated breast and epithelial ovarian cancer (EOC). However, about 50% of high grade serous ovarian cancers (HGSOC) present with HRD due to epigenetic BRCA1 inactivation, as well as genetic/epigenetic inactivation(s) of other HR genes, a feature known as “BRCAness”. Therefore, there is a potential for extending the use of PARPis to these patients if HR status can be identified.

Methods

We have developed a 3D (spheroid) functional assay to assess the sensitivity of two PARPis (niraparib and olaparib) in ascites-derived primary cell cultures (AsPCs) from HGSOC patients. A method for AsPCs preparation was established based on a matrix (agarose), allowing for easy isolation and successive propagation of monolayer and 3D AsPCs. Based on this method, we performed cytotoxicity assays on 42 AsPCs grown both as monolayers and spheroids.

Results

The response to PARPis treatment in monolayer AsPCs, was significantly higher, compared to 3D AsPCs, as 88% and 52% of the monolayer AsPCs displayed sensitivity to niraparib and olaparib respectively, while 66% of the 3D AsPCs were sensitive to niraparib and 38% to olaparib, the latter being more consistent with previous estimates of HRD (40%–60%) in EOC. Moreover, niraparib displayed a significantly stronger cytotoxic effect in both in 3D and monolayer AsPCs, which was confirmed by consecutive analyses of the HR pathway activity (γH2AX foci formation) in PARPis-sensitive and resistant AsPCs. Global gene expression comparison of 6 PARPi-resistant and 6 PARPi-sensitive 3D AsPCs was indicative for the predominant downregulation of numerous genes and networks with previously demonstrated roles in EOC chemoresistance, suggesting that the PARPis-sensitive AsPCs could display enhanced sensitivity to other chemotherapeutic drugs, commonly applied in cancer management. Microarray data validation identified 24 potential gene biomarkers associated with PARPis sensitivity. The differential expression of 7 selected biomarkers was consecutively confirmed by immunohistochemistry in matched EOC tumor samples.

Conclusion

The application of this assay and the potential biomarkers with possible predictive significance to PARPis therapy of EOC patients now need testing in the setting of a clinical trial.

Dependence and Guidance Receptors-DCC and Neogenin-In Partial EMT and the Actions of Serine Proteases

The Epithelial-Mesenchymal Transition (EMT) is an important concept in understanding the processes of oncogenesis, especially with respect to the relationship between cell proliferation and metastatic properties such as spontaneous cell motility, chemotaxic migration and tissue invasion. EMT is now recognized as a more complex phenomenon than an all-or-nothing event, in which different components of the EMT may have distinct roles in the physio-pathological regulation of cell function and which may in turn depend on differential interactions with cell constituents and metabolic products. This mini-review summarizes recent work on the induction of cancer properties in parallel with the presence of EMT activities in the presence of serine proteases, with the focus on those tumor suppressors known as "dependence" receptors such as neogenin and Deleted in Colorectal Cancer (DCC). It is concluded that various forms of partial EMT should be given more detailed investigation and consideration as the results could have valuable implications for the development of disease-specific and patient-specific therapies.

A single-nucleotide polymorphism in lnc-LAMC2-1:1 interferes with its interaction with miR-128 to alter the expression of deleted in colorectal cancer and its effect on the survival rate of subjects with ovarian cancer

This study aimed to identify the association between lnc-LAMC2-1:1 polymorphism rs2147578 and the recurrence of ovary cancer, as well as to study the underlying mechanism of rs2147578 in ovary cancer. Real-time polymerase chain reaction, Western blot analysis, immunohistochemistry, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Logrank test, and Kaplan-Meier analysis were carried out to explore the role of rs2147578 in ovary cancer. No obvious difference was observed concerning all clinical characteristics among 90 patients genotyped as CC (N = 28), CG (N = 38), and GG (N = 24) in their rs2147578 polymorphism. In addition, the subjects carrying the CC genotype had longer recurrence-free survival time and showed a lower level of malignancy compared with those carrying CG and GG genotypes. Lnc-LAMC2-1:1 and miR-128 were lowly expressed in the CC group, while deleted in colorectal cancer (DCC) was highly expressed in the CC group. Furthermore, DCC was identified as a target gene of miR-128, and miR-128 mimics decreased the luciferase activity of cells cotransfected with wild-type DCC 3'-untranslated region. Lnc-LAMC2:1-1 directly targeted and affected miR-128 expression, and the G allele in lnc-LAMC2-1:1 rs2147578 upregulated miR-128 expression. Transfection with a miR-128 precursor evidently downregulated the expression of lnc-LAMC2-1:1, miR-128, and DCC expression, but did not affect the expression of ABCC5 and body mass index. Finally, miR-128 precursor promoted cell proliferation and inhibited cell apoptosis. Compared with lnc-LAMC2-1:1 rs2147578C allele, the G allele increases the risk of ovarian cancer by reducing the binding between lnc-LAMC2-1:1 and miR-128-3p, which in turn further decreases the expression of DCC and inhibits cell apoptosis.

Serine protease modulation of Dependence Receptors and EMT protein expression

Expression of the tumour suppressor Deleted in Colorectal Cancer (DCC) and the related protein neogenin is reduced by the mammalian serine protease chymotrypsin or the bacterial serine protease subtilisin, with increased cell migration. The present work examines whether these actions are associated with changes in the expression of cadherins, β-catenin and vimentin, established markers of the Epithelial-Mesenchymal Transition (EMT) which has been linked with cell migration and tumour metastasis. The results confirm the depletion of DCC and neogenin and show that chymotrypsin and subtilisin also reduce expression of β-catenin in acutely prepared tissue sections but not in human mammary adenocarcinoma MCF-7 or MDA-MB-231 cells cultured in normal media, or primary normal human breast cells. A loss of β-catenin was also seen in low serum media but transfecting cells with a dcc-containing plasmid induced resistance. E-cadherin was not consistently affected but vimentin was induced by low serum-containing media and was increased by serine proteases in MCF-7 and MDA-MB-231 cells in parallel with increased wound closure. Vimentin might contribute to the promotion of cell migration. The results suggest that changes in EMT proteins depend on the cells or tissues concerned and do not parallel the expression of DCC and neogenin. The increased cell migration induced by serine proteases is not consistently associated with the expression of the EMT proteins implying either that the increased migration may be independent of EMT or supporting the view that EMT is not itself consistently related to migration. (241).

Loss of E-cadherin disrupts ovarian epithelial inclusion cyst formation and collective cell movement in ovarian cancer cells

Increased inclusion cyst formation in the ovary is associated with ovarian cancer development. We employed in vitro three-dimensional (3D) organotypic models formed by normal human ovarian surface epithelial (OSE) cells and ovarian cancer cells to study the morphologies of normal and cancerous ovarian cortical inclusion cysts and the molecular changes during their transitions into stromal microenvironment. When compared with normal cysts that expressed tenascin, the cancerous cysts expressed high levels of laminin V and demonstrated polarized structures in Matrigel; and the cancer cells migrated collectively when the cyst structures were positioned in a stromal-like collagen I matrix. The molecular markers identified in the in vitro 3D models were verified in clinical samples. Network analysis of gene expression of the 3D structures indicates concurrent downregulation of transforming growth factor beta pathway genes and high levels of E-cadherin and microRNA200 (miR200) expression in the cancerous cysts and the migrating cancer cells. Transient silencing of E-cadherin expression in ovarian cancer cells disrupted cyst structures and inhibited collective cell migration. Taken together, our studies employing 3D models have shown that E-cadherin is crucial for ovarian inclusion cyst formation and collective cancer cell migration.

Low-grade epithelial ovarian cancer: a number of distinct clinical entities?

PURPOSE OF REVIEW

The purpose of this study is to summarize the contemporary understanding of low-grade epithelial ovarian cancers.

RECENT FINDINGS

Low-grade serous ovarian cancer is biologically distinct from high-grade serous ovarian cancer. It is associated with a high incidence of K-RAS and B-RAF mutations. Although described as indolent due to median progression-free and overall survivals of 20 and 99 months, respectively, with a median age of diagnosis of 43 years, it accounts for a significant number of patient-years lost. Retrospective studies suggest response rates of 5% for chemotherapy and 9% for antioestrogen therapy. A prospective study of the mitogen-activated protein kinase kinase inhibitor selumetinib (response rate 15%) and retrospective bevacizumab studies suggest that these may be more effective approaches.Limited retrospective clinical data and even more sparse molecular data suggest that similar distinctions may exist between low-grade endometrioid and mucinous ovarian cancers and their respective high-grade counterparts, but more research is required in order to clarify the biological differences and the implications that these have for management.

SUMMARY

The results of phase III mitogen-activated protein kinase kinase inhibitor studies in low-grade serous ovarian cancer and further clinical and biological assessment of low-grade endometrioid and mucinous ovarian cancers are urgently required.

Epigenetic down-regulated DDX10 promotes cell proliferation through Akt/NF-κB pathway in ovarian cancer

Ovarian cancer contributes to the majority of ovarian cancer, while the molecular mechanisms remain elusive. Recently, some DEAD box protein 1 has been reported play a tumor suppressor role in ovarian cancer progression. However, the functions of DEAD box protein (DDX) members in ovarian cancer development remain largely unknown. In current study, we retrieved GEO databases and surprisingly found that DDX10 is significantly down-regulated in ovarian cancer tissues compared with normal ovary. These findings suggest that DDX10 might also play a suppressive role in ovarian cancer. We then validated the down-regulated expression pattern of DDX10 in fresh ovarian cancer tissues. Furthermore, both loss- and gain-functions assays reveal that the down-regulated DDX10 could promote ovarian cancer proliferation in vitro and the xenograft subcutaneous tumor formation assays confirmed these findings in vivo. In addition, we found that DDX10 is epigenetic silenced by miR-155-5p in ovarian cancer. Moreover, we further preliminary illustrated that down-regulated DDX10 promotes ovarian cancer cell proliferation through Akt/NF-κB pathway. Taken together, in current study, we found a novel tumor suppressor, DDX10, is epigenetic silenced by miR-155-5p in ovarian cancer, and the down-regulated expression pattern of DDX10 promotes ovarian cancer proliferation through Akt/NF-κB pathway. Our findings shed the light that DDX families might be a novel for ovarian cancer treatment.

Novel high-grade serous epithelial ovarian cancer cell lines that reflect the molecular diversity of both the sporadic and hereditary disease

Few cell line models of epithelial ovarian cancer (EOC) have been developed for the high-grade serous (HGS) subtype, which is the most common and lethal form of gynaecological cancer. Here we describe the establishment of six new EOC cell lines spontaneously derived from HGS tumors (TOV2978G, TOV3041G and TOV3291G) or ascites (OV866(2), OV4453 and OV4485). Exome sequencing revealed somatic TP53 mutations in five of the cell lines. One cell line has a novel BRCA1 splice-site mutation, and another, a recurrent BRCA2 nonsense mutation, both of germline origin. The novel BRCA1 mutation induced abnormal splicing, mRNA instability, resulting in the absence of BRCA1 protein. None of the cell lines harbor mutations in KRAS or BRAF, which are characteristic of other EOC subtypes. SNP arrays showed that all of the cell lines exhibited structural chromosomal abnormalities, copy number alterations and regions of loss of heterozygosity, consistent with those described for HGS. Four cell lines were able to produce 3D-spheroids, two exhibited anchorage-independent growth, and three (including the BRCA1 and BRCA2 mutated cell lines) formed tumors in SCID mice. These novel HGS EOC cell lines and their detailed characterization provide new research tools for investigating the most common and lethal form of EOC.

Changes of TIZ expression in epithelial ovarian cancer cells

OBJECTIVE

To study the change of TIZ expression in epithelial ovarian cancer cells.

METHODS

HO8910 cells were transinfected with siRNA to inhibit the expression of TIZ. pcDNA3.1-TIZ vectors were combined to increase the TIZ expression level. The cell viability, colony forming efficiency and cycle distribution of HO8910, HO8910/NC, HO8910/pcDNA3.1-NC, HO8910/TIZ-573 and H08910/pcDNA3.1-TIZ were compared, and the invasion rate, migration rate and adhesion rate between 5 groups of cells were compared.

RESULTS

Compared with those of HO8910, HO8910/NC and HO8910/pcDNA3.1-NC, the cell viability, colony forming efficiency and cell cycle distribution of HO8910/TIZ-573 were increased, while the indexes of H08910/pcDNA3.1-NC were decreased with statistical significant difference (P<0.05). There was no statistical significant difference in the invasion rate, migration rate and adhesion rate between 5 groups of cells (P>0.05).

CONCLUSIONS

The expression of TIZ can inhibit the proliferation of epithelial ovarian cancer cells.

Updates and emerging therapies for rare epithelial ovarian cancers: one size no longer fits all

Epithelial ovarian carcinoma consists of not one, but several, entities. A number of subtypes exist, including high-grade and low-grade serous carcinomas, clear cell, endometrioid carcinoma and mucinous carcinoma. Historically, women with epithelial ovarian cancer have been treated similarly and "lumped" in the same cooperative group treatment trials, irrespective of their tumor subtype. Recently, however, differences in epidemiology, tumor biology, tumor marker expression and treatment responses have been elucidated among the histologic subtypes, with a clear distinction emerging between the Type I, lower grade tumors and Type 2, higher grade epithelial malignancies. A mounting body of research demonstrates that a "one-size-fits-all" treatment approach to epithelial ovarian tumors is no longer relevant, especially for the Type I subtypes. Indeed, with the exception of high-grade serous carcinoma, most other epithelial subtypes exhibit some degree of chemotherapy resistance, rendering treatment problematic, especially in the setting of advanced disease. This review summarizes the genetic, molecular, and clinical differences of the more rare, but clinically important, Type I epithelial ovarian tumors. Additionally, a critical appraisal of both historical and contemporary treatment approaches and the rationale for targeted therapies are emphasized.

CYR61 overexpression associated with the development and poor prognosis of ovarian carcinoma

Cysteine-rich 61 (CYR61) has been proven to be an oncogene with potential predictive and prognostic implications in a variety of human cancers. However, the expression pattern of CYR61 and its role in ovarian carcinoma remains largely unknown. In this study, the mRNA and protein levels of CYR61 in normal ovaries and ovarian carcinoma tissues were evaluated using reverse transcription-polymerase chain reaction, immunohistochemistry, and Western blotting. Compared to normal ovarian tissues, the mRNA and protein levels of CYR61 were significantly higher in ovarian carcinoma tissues. Moreover, receiver operating characteristic (ROC) curve analysis, Spearman's rank correlation, Kaplan-Meier plots, and the Cox proportional hazards regression model were used to investigate the potential association of the CYR61 protein with the development of ovarian carcinoma in an ovarian carcinoma cohort. Based on ROC curve analysis, high expression of CYR61 was defined as a tumor in which more than 70 % of cells were positively stained. Based on this cutoff value, high expression of CYR61 was detected in 51.5 % of invasive carcinomas, 35.3 % of borderline tumors, 25.9 % of cystadenomas, and 20 % in the normal ovaries. In ovarian carcinomas, CYR61 overexpression was associated with advanced FIGO stage. Univariate survival analysis on the ovarian carcinoma cohorts showed that overexpression of CYR61 was associated with poor survival of ovarian cancer patients. Multivariate analysis suggested that the protein level of CYR61 was an independent and significant prognostic factor for ovarian carcinoma. Our results suggest that the CYR61 protein is an important and independent biomarker for prognostic implications of ovarian carcinoma.

New and potential clinical applications of KRAS as a cancer biomarker

IMPORTANCE OF THE FIELD

KRAS mutation is the most common oncogenic alteration in various human cancers. Recently, KRAS has emerged as an important predictive biomarker in common malignancies such as metastatic colorectal cancer (mCRC) and non-small cell lung cancer (NSCLC). This work aims to discuss the clinical impact of the KRAS mutation status on state-of-the-art treatment approaches, including epidermal growth factor receptor (EGFR)-targeted therapies.

AREAS COVERED IN THIS REVIEW

This review considers the potential of KRAS to serve as a diagnostic, prognostic or predictive biomarker in various cancers, including those of the lung, colon/rectum, pancreas, ovary and endometrium.

WHAT THE READER WILL GAIN

KRAS mutations in mCRC and NSCLC primary tumors predict resistance to EGFR-targeted therapy. In pancreatic cancer, KRAS may prove useful as a diagnostic biomarker to screen for early neoplasia. Furthermore, quantitative KRAS mutation analysis could have the potential to distinguish pancreatic cancer from other conditions such as chronic pancreatitis. With respect to ovarian and endometrial cancer, further studies should focus on determining reliable biomarkers for predicting response to EGFR-targeted therapy. Besides EGFR inhibition, KRAS may also serve as a diagnostic and predictive biomarker for evolving therapies directed against mutant RAS proteins.

TAKE HOME MESSAGE

KRAS has been recognized as an outstanding predictive biomarker to select mCRC and NSCLC patients for EGFR-targeted therapies; however, multi-determinant approaches including other molecular markers should facilitate the identification of patients likely to respond to such therapies.

Natural history and outcome of mucinous carcinoma of the ovary

OBJECTIVE

We performed a population-based analysis to compare the clinical characteristics of women with mucinous tumors with women with other epithelial tumors.

STUDY DESIGN

The Surveillance, Epidemiology, and End Results database was queried to identify all women with epithelial ovarian cancer diagnosed from 1988 to 2007. The natural history, clinical characteristics, and survival of women with serous tumors were compared with women with mucinous carcinomas.

RESULTS

A total of 40,571 women including 4811 with mucinous carcinomas (11.9%) were identified. Among women with stage I neoplasms, the presence of mucinous histology had no effect on either cancer-specific survival (hazard ratio, 0.87; 95% confidence interval, 0.74-1.04). Survival was inferior in patients with advanced-stage mucinous compared with serous tumors. The hazard ratio for cancer-specific survival for women with stage III mucinous tumors was 1.55 (95% confidence interval, 1.43-1.96).

CONCLUSION

Although survival for early-stage mucinous and serous tumors is similar, survival for advanced-stage mucinous neoplasms is inferior to that of serous carcinomas.

Detection of serum anti-p53 antibodies from patients with ovarian cancer in China: correlation to clinical parameters

BACKGROUND

Ovarian cancer has been one of the most common malignant tumor among women in China. The aims of this research were to increase the detection efficiency of anti-p53 antibodies in the sera from patients with ovarian cancer and to assist the diagnosis for patients with ovarian cancer.

METHODS

The hybrid phage displaying the immunodominant epitope SQAMDDLMLS in p53 N-terminal region was constructed and the fusion protein was prepared and purified. Ninety-two nonselected Chinese women with ovarian cancer were involved in this study. Tumor p53 overexpression was assessed by immunohistochemical analysis of tissue sections. Serum antibodies to p53 were also detected by enzyme-linked immunosorbent assay (ELISA) using recombinant human wild-type p53 protein and the hybrid phage as the coating antigen respectively. Furthermore, the correlations between the anti-p53 antibodies and clinicopathological parameters were analyzed.

RESULTS

The positive rate of anti-p53 antibodies in the patients with ovarian cancer was increased (39.1%, 36/92) through the combination of the two ELISA methods compared with each method. The anti-p53 antibodies were not associated with the clinicopathologic parameters, while there was a significant correlation between the presence of p53 Abs and tissue overexpression of p53 in ovarian cancer.

CONCLUSION

These preliminary results demonstrate that the combination of the two ELISA methods increased the positive rate of anti-p53 antibodies in patients with ovarian cancer and provided a useful marker to complement routine clinical diagnosis for patients with ovarian cancer.

Genetic variants in MicroRNA biosynthesis pathways and binding sites modify ovarian cancer risk, survival, and treatment response

MicroRNAs (miRNA) play important roles in tumorigenesis. Genetic variations in miRNA processing genes and miRNA binding sites may affect the biogenesis of miRNA and the regulatory effect of miRNAs to their target genes, hence promoting tumorigenesis. This study analyzed 226 single nucleotide polymorphisms (SNP) in miRNA processing genes and miRNA binding sites in 339 ovarian cancer cases and 349 healthy controls to assess association with cancer risk, overall survival, and treatment response. Thirteen polymorphisms were found to have significant association with risk. The most significant were 2 linked SNPs (r(2) = 0.99), rs2740351 and rs7813 in GEMIN4 [odds ratio (OR) = 0.71; 95% confidence interval (CI), 0.57-0.87 and OR = 0.71; 95% CI, 0.57-0.88, respectively]. Unfavorable genotype analysis showed the cumulative effect of these 13 SNPs on risk (P for trend < 0.0001). Potential higher order gene-gene interactions were identified, which categorized patients into different risk groups according to their genotypic signatures. In the clinical outcome study, 24 SNPs exhibited significant association with overall survival and 17 SNPs with treatment response. Notably, patients carrying a rare homozygous genotype of rs1425486 in PDGFC had poorer overall survival [hazard ratio (HR) = 2.69; 95% CI, 1.67-4.33] and worse treatment response (OR = 3.38; 95% CI, 1.39-8.19), compared to carriers of common homozygous and heterozygous genotypes. Unfavorable genotype analyses also showed a strong gene-dosage effect with decreased survival and increased risk of treatment nonresponse in patients with greater number of unfavorable genotypes (P for trend < 0.0001). Taken together, miRNA-related genetic polymorphisms may impact ovarian cancer predisposition and clinical outcome both individually and jointly.

Rab5a overexpression promoting ovarian cancer cell proliferation may be associated with APPL1-related epidermal growth factor signaling pathway

Rab5a is a regulatory guanosine triphosphatase that is associated with the transport and fusion of endocytic vesicles, and participates in regulation of intracellular signaling pathways embraced by cells to adapt to the specific environment. Rab5a is also correlated with lung, stomach, and hepatocellular carcinomas. Here, we detected Rab5a in paraffin-embedded samples of 20 ovarian cysts, 20 benign cystadenomas, and 39 ovarian cancers by immunohistochemistry, and observed that Rab5a expression was significantly higher in ovarian cancer (P = 0.0001). By setting up stable HO-8910 cell lines expressing Rab5a or dominant negative Rab5a (Rab5a:S34N), we found that Rab5a overexpression enhanced the cell growth by promoting G1 into S phase. In contrast, Rab5a:S34N inhibited this process. Additionally, APPL1 (adaptor protein containing PH domain, PTB domain, and Leucine zipper motif), a downstream effector of Rab5a, was also involved in promoting HO-8910 cell cycle progress. But this function was blocked by Rab5a:S34N. Laser scanning confocal microscopy represented the colocalization of APPL1 and Rab5a in the plasmolemma, which changed with the time of epidermal growth factor (EGF) stimulation. We also found APPL1 could transfer from the membranes into the nucleus where it interacted with NuRD/MeCP1 (the nucleosome remodeling and histone deacetylase multiprotein complex). NuRD is reported to be involved in the deacetylation of histone H3 and H4 to regulate nuclear transcription. So Rab5a promoted proliferation of ovarian cancer cells, which may be associated with the APPL1-related epidermal growth factor signaling pathway.

Lost expression of DCC gene in ovarian cancer and its inhibition in ovarian cancer cells

Ovarian cancer is a leading cause of cancer-related women mortality in China. In recent years, the molecular mechanisms involved in ovarian carcinoma development and/or progression have been intensely studied, and several genes have been identified. Deleted in Colorectal Carcinoma (DCC), is an important tumor suppressor gene, which is inactivated in many kinds of tumors, and its function(s) is not clarified. Even though the lost expression of DCC occurred in later stages of multistep colorectal carcinogenesis, its contribution to the onset or progression of ovarian cancer is not fully understood. To investigate DCC expression in ovarian cancer, we studied 254 clinical samples by RT-PCR. Our results revealed that 52% malignant ovarian cancer did not express DCC gene. By contrast, DCC expression was observed in all normal ovary tissues and 80% benign ovarian tumors. Obviously, there was a significant correlation between DCC expression and ovarian cancer, especially in the epithelial ovarian cancer. The present study also suggested that the loss expression of DCC occurred more frequently in the cases of later clinical stage, higher pathological grade, and poorer prognosis. In the other part of this study, we further explored DCC expression after transfection in two kinds of ovarian cancer cell lines, namely SKOV3 cell and HO-8910 cell, using RT-PCR and immunocytochemistry. The results indicated that DCC expressed in SKOV3-DCC and HO-8910-DCC cells, and ultrastructural analysis showed the appearance of apoptotic features in them. Furthermore, cell growth was markedly down-regulated in above groups of cells, indicating that transfection with the DCC constructs can suppress the growth of tumor cells. In conclusion, our results suggest an association of lost expression of DCC with the ovarian cancer, and DCC gene may inhibit the growth of ovarian carcinoma cells. However, this result needs further trials with a larger sample.

Mac-2 binding protein and galectin-3 expression in mucinous tumours of the ovary: an annealing control primer system and immunohistochemical study

AIM

We used a new differential display method, the annealing control primer (ACP) system, to analyse the differentially expressed genes in mucinous ovarian tumours. To verify the corresponding target gene, immunohistochemical staining was performed on various epithelial tumours of the ovary.

METHODS AND RESULTS

The ACP-based reverse transcriptase-polymerase chain reaction revealed that 21 genes were upregulated in the mucinous ovarian adenoma and 14 genes were upregulated in the mucinous ovarian carcinoma. Among them, we selected one upregulated gene, the Mac-2 binding protein (Mac-2 BP), and verified the expression of the Mac-2 BP and its ligand, galectin-3, in a variety of epithelial ovarian tumours by immunohistochemistry. Positive expression of the Mac-2 BP was significantly higher in the mucinous ovarian tumours compared to the other epithelial tumours. Mac-2 BP expression was significantly increased in the borderline and malignant tumours compared to the benign tumours. Galectin-3 expression was more frequent in clear cell carcinomas, serous tumours and mucinous tumours than in endometrioid and transitional tumours. However, there were no differences in galectin-3 expression in comparisons among benign, borderline and malignant mucinous and serous tumours.

CONCLUSION

These data indicate that the Mac-2 BP may play a role in the development and progression of mucinous ovarian tumours.

Molecular characterization of a new ovarian cancer cell line, YDOV-151, established from mucinous cystadenocarcinoma

Ovarian cancer is a leading cause of death among gynecological malignancies. Established cancer cell lines are useful tools for clinical and basic researches. We have therefore established a new human ovarian cancer cell line, YDOV-151, derived from the mucinous cystadenocarcinoma and characterized it by the microarray analyses. A mucinous origin of the YDOV-151 was evident from light microscopy, and its epithelial-like character was confirmed with electron microscopy. No pathogenic mutations were found in the BRCA1 and BRCA2 genes. The subcutaneous transplantation of YDOV-151 cells into nude mice successfully induced the tumor mass after 3 weeks. cDNA microarray analysis revealed 1,926 genes (> 2-fold differences, P < 0.05) that distinguished the YDOV-151 from human ovarian surface epithelial (HOSE) cells. To identify candidate biomarkers, we selected five genes (SFN, RGC32, CDCA7, LAMP3, and SLCO4A1), each of which was up-regulated (> 7-fold) in YDOV-151 and had an available antibody assay for further validation. In SYBR Green real-time PCR, the relative expression levels of RGC32 (651-fold), LAMP3 (1,930-fold), and SLCO4A1 (20,598-fold) were significantly higher in YDOV-151 than in HOSEs (P < 0.001). RGC32 may be involved in cell cycle regulation, LAMP3 may promote metastasis, and SLCO4A1 is a member of anion-transporting polypeptides. The newly established ovarian cancer cell line, YDOV-151, would be a useful model for elucidating the biology and the pathogenesis of mucinous cystadenocarcinoma. In addition, the identification and validation of up-regulated genes may provide a genetic approach for identifying biomarkers in ovarian cancer.

KRAS mutation analysis in ovarian samples using a high sensitivity biochip assay

Background

Mutations in the KRAS gene are one of the most frequent genetic abnormalities in ovarian carcinoma. They are of renewed interest as new epidermal growth factor receptor (EGFR)-targeted therapies are being investigated for use in ovarian carcinoma. As KRAS mutations are associated with poor response and resistance to EGFR-targeting drugs, this study was conducted to obtain more information on the spectrum of KRAS mutations in ovarian carcinoma.

Methods

The presence of KRAS mutations in codon 12 and 13 was analyzed in frozen and formalin-fixed paraffin-embedded (FFPE) tissue with a low density biochip platform. 381 malignant (29 borderline malignancy, 270 primary carcinomas, and 82 recurrent carcinomas) and 22 benign tissue samples from a total of 394 patients were examined. KRAS mutational status of each sample was correlated with dignity, FIGO stage, grade, histology, and survival.

Results

KRAS mutations were found in 60 (15%) samples with 58 samples deriving from malignant tissue and 2 samples deriving from benign tissue. In 55 (92%) samples codon 12 was found to be mutated. Frozen and FFPE samples concurred with respect to KRAS mutation status.

Conclusion

KRAS mutation is a common event in ovarian cancer primarily in carcinomas of lower grade, lower FIGO stage, and mucinous histotype. The KRAS mutational status is no prognostic factor for patients treated with standard therapy. However, in line with experience from colorectal cancer and non-small-cell-lung cancer (NSCLC), it may be important for prediction of response to EGFR-targeted therapies.

Lipocalin2 expressions correlate significantly with tumor differentiation in epithelial ovarian cancer

We recently identified lipocalin2 (LCN2) as being upregulated in ovarian cancer cell lines. The purpose of this study was to validate LCN2 upregulation in ovarian cancers and to investigate its potential as a serum biomarker. We assayed LCN2 expression in ovarian cancers using real-time PCR and IHC. To evaluate the potential of LCN2 as a biomarker, we measured serum LCN2 levels in 54 ovarian cancers, 15 borderline and 53 benign ovarian tumors, and 90 healthy controls. SYBR green PCR and IHC showed LCN2 overexpression in ovarian cancers. LCN2 immunoreactivity was significantly associated with tumor differentiation (p=0.009), as well-differentiated tumors showed the highest LCN2 expression. Serum LCN2 level in ovarian cancer was significantly higher than in the other study groups (p<0.001), and in accordance with IHC results, it also correlated with tumor differentiation, with well-differentiated tumors having the highest value. The sensitivity and specificity of LCN2 in detecting ovarian cancer was 72.2% and 50.4%, respectively. By Cox univariate analysis, LCN2 positivity was an independent prognostic factor for overall survival (hazard ratio = 1.47, p=0.012). In conclusion, LCN2 expressions are upregulated and related to tumor differentiation in ovarian cancers and should be included in future research assessing potential biomarkers for ovarian cancer.

Potential benefit of Sunitinib in recurrent and refractory ovarian clear cell adenocarcinoma

Ovarian clear cell adenocarcinoma (OCCA) is a unique biological subtype of epithelial ovarian cancer, with a similar gene profile to renal cell carcinoma (RCC). Sunitinib is a vascular endothelial growth factor receptor tyrosine kinase inhibitor with proven antitumor activity in RCC and a rational biological option for treatment of OCCA. A 60-year-old woman presented with recurrent and refractory stage IA OCCA, after 9 years of remission. Sunitinib was initiated as fifth-line chemotherapy, associated with cystic degeneration of liver metastasis and a short downward trend in her CA125 level. Recurrent and refractory OCCA may respond to Sunitinib. Clinical trials are needed to objectively confirm these findings, as benefit may be limited in patients with extensively pretreated tumors.

Mucinous ovarian cancer

Mucinous epithelial ovarian cancer (mEOC) accounts for approximately 10% of EOCs. Patients presenting with early-stage disease have an excellent prognosis, however, those with advanced disease have a poor outcome with relative resistance to standard ovarian cancer chemotherapy. Molecular and genetic studies demonstrate differences between mucinous and serous EOC supporting the concept that these tumors develop along separate pathways. Together with the observed differences in clinical behavior and outcome for mEOC, there is a need to develop specific therapeutic strategies for this histologic subtype. The relative rarity of advanced mEOC has resulted in few patients enrolled in major ovarian cancer trials. The results of such trials may not necessarily reflect those specific to mEOC. Separate trials testing alternative chemotherapeutics are required. Metastatic mucinous tumors from other sites such as the gastrointestinal tract may present with ovarian involvement. For all mucinous tumors of the ovary, establishing primary as opposed to metastatic cancers is important. Clinical presentation, tumor markers, histologic, and immunohistochemical features are helpful in distinguishing most cases.

Molecular biomarkers for cancer detection in blood and bodily fluids

Cancer is a major and increasing public health problem worldwide. Traditionally, the diagnosis and staging of cancer, as well as the evaluation of response to therapy have been primarily based on morphology, with relatively few cancer biomarkers currently in use. Conventional biomarker studies have been focused on single genes or discrete pathways, but this approach has had limited success because of the complex and heterogeneous nature of many cancers. The completion of the human genome project and the development of new technologies have greatly facilitated the identification of biomarkers for assessment of cancer risk, early detection of primary cancers, monitoring cancer treatment, and detection of recurrence. This article reviews the various approaches used for development of such markers and describes markers of potential clinical interest in major types of cancer. Finally, we discuss the reasons why so few cancer biomarkers are currently available for clinical use.

Treatment issues in clear cell carcinoma of the ovary: a different entity?

BACKGROUND

Ovarian clear cell carcinoma (OCCC) is a distinct histopathologic subtype of epithelial ovarian cancer (EOC) with an incidence of <5% of all ovarian malignancies. Our goal was to review the clinical features and management of patients with OCCC.

METHODS AND RESULTS

We performed a PubMed search using the phrase "clear cell ovarian cancer." We reviewed 54 articles referring to OCCC. OCCC patients have a high incidence of stage I disease and frequently present with a large pelvic mass. Recurrences are more frequent with this entity than with other types of EOC. The clinical management of advanced EOC includes maximal cytoreduction and platinum plus paclitaxel-based chemotherapy. The survival rates of patients with advanced OCCC are lower than those of patients with advanced serous EOC (serous subtype). The poor response rate to platinum-based regimens may be related to the intrinsic chemoresistance of these tumors. Despite their aggressive clinical course, OCCCs are still treated similarly to the other EOCs at the present time, because the rarity of these tumors prevents the conduction of randomized studies.

CONCLUSION

Novel treatment approaches should be adopted in OCCC. Molecular-targeted therapies and effective new agents without cross-resistance to platinum compounds should be evaluated in a prospective clinical trial in OCCC.

Automated quantitative analysis of DCC tumor suppressor protein in ovarian cancer tissue microarray shows association with β-catenin levels and outcome in patients with epithelial ovarian cancer

BACKGROUND

The deleted in colorectal cancer (DCC) protein, the product of DCC tumor suppressor gene, is frequently altered in cancer. Preclinical data demonstrate that DCC regulates beta-catenin levels. Here, we sought to determine the association of DCC with beta-catenin protein levels, clinicopathological parameters and patient outcome in ovarian cancer using a method of in situ compartmentalized protein analysis.

METHODS

A tissue array composed of 150 advanced-stage ovarian cancers, treated with surgical debulking and platinum-paclitaxel (Taxol) combination chemotherapy, was constructed. For evaluation of protein expression, we used an immunofluorescence-based method of automated in situ quantitative measurement of protein analysis (AQUA).

RESULTS

One hundred and twelve patients (74%) had sufficient tissue for AQUA. The median follow-up time for the entire cohort was 33 months. Patients with low nuclear DCC expression had a 3-year progression-free survival (PFS) rate of 0% compared with 33% of those with high DCC expression (P = 0.0067). In multivariate analysis, low nuclear DCC expression level retained its prognostic significance for PFS. Between DCC and beta-catenin, a significant relationship was found, where tumors with low DCC had low beta-catenin and vice versa (P = 0.003).

CONCLUSIONS

Low nuclear DCC levels predict for poor patient outcome in epithelial ovarian cancer. DCC may exert its antitumor function, in part, through regulation of beta-catenin levels.

Advanced stage clear-cell epithelial ovarian cancer: the Hellenic Cooperative Oncology Group experience

PURPOSE

Ovarian clear-cell carcinomas (OCCC) are known to be possibly resistant to platinum-based chemotherapy and to have a poorer prognosis with respect to other subtypes of epithelial ovarian cancer (EOC). This study was undertaken to compare response and survival to platinum-based chemotherapy between patients with advanced stage III and IV OCCC and serous EOC (sEOC).

PATIENTS AND METHODS

A retrospective analysis was performed in patients with advanced stage of OCCC treated with first-line platinum-based chemotherapy in the context of several study protocols of the Hellenic Cooperative Oncology Group (HeCOG) between 1/2/1987 and 31/10/2003. The outcome was compared to that of patients with sEOC treated according to the same protocols during the same study period.

RESULTS

One hundred and five patients (35 stage III and IV OCCC, 70 stage III and IV sEOC) treated with platinum-based chemotherapy were analyzed. The overall response rate for OCCC was 45% (complete response 25%) (95% CI, 23.1% to 68.5%) and 81% (complete response 46%) (95% CI, 67.4% to 91.1%) for sEOC. The overall response rate was significantly higher for sEOC (P = 0.008). In the subgroup of stage III patients, the rate of complete responders was higher among sEOC patients (P = 0.023). After a median follow-up of 61.1 months, median survival and time to tumor progression were not significantly different between the two groups (25.1 months [95% CI 11.7 to 38.5 months] versus 49.1 months [95% CI 36.5 to 61.6 months], P = 0.141, 12.0 months [95% CI 6.5 to 17.3 months] versus 18.0 months [95% CI 14.7 to 21.6 months], P = 0.384, respectively).

CONCLUSION

Patients with OCCC have significantly lower response to platinum-based first-line chemotherapy compared to patients with sEOC. This low response to platinum-based chemotherapy was not translated in significantly shorter survival. The current study outcomes are provocative and suggest that a new strategy for chemotherapy in OCCC should be adopted, possibly one that focuses on new agents without cross-resistance to platinum agents.

Ovarian carcinomas: CCN genes are aberrantly expressed and CCN1 promotes proliferation of these cells

PURPOSE

The connective tissue growth factor/cysteine-rich 61/nephroblastoma overexpressed (CCN) family consists of six matricellular proteins that are involved in various cellular functions, such as proliferation, development, and angiogenesis. The purpose of this study was to explore the possibility that CCN genes are involved in ovarian cancers.

EXPERIMENTAL DESIGN

We quantified CCN expression in a series of 59 ovarian cancers using quantitative real-time reverse transcription-PCR. CCN1 protein levels were further determined by immunohistochemistry and Western blot analysis. Overexpression and inhibition of CCN1 expression by small interfering RNA were used to examine its role in ovarian cancer cell proliferation in vitro and in vivo.

RESULTS

We found dysregulation of levels of the various CCN mRNAs in ovarian cancers compared with their expression in normal whole ovaries. Expression of CCN1 protein was detected in normal ovarian epithelial cells and ovarian tumors as well as in ovarian cancer cell lines. Furthermore, estrogen increased CCN1 mRNA and protein levels in ovarian cancer cells. Ectopic expression of CCN1 enhanced the growth of ovarian cancer cells in liquid culture, whereas inhibition of its expression decreased proliferation and increased apoptosis in these cells. The observed changes in cell growth were accompanied with activation of Akt and extracellular signal-regulated kinase (ERK) signaling pathways. Stable expression of CCN1 in SKOV3 cells significantly increased tumorigenicity in nude mice. Finally, overexpression of CCN1 conferred resistant to carboplatin-induced apoptosis in SKOV3 cells.

CONCLUSIONS

This is the first study to show abnormalities in CCN expression in ovarian carcinomas. Furthermore, our results suggest that CCN1 may play a role in ovarian carcinogenesis by stimulating survival and antiapoptotic signaling pathways.

Role of chemotherapy in the management of epithelial ovarian cancer

The management of ovarian cancer continues to provide major challenges and debates about optimal treatment. For first-line therapy there remain discussions about optimal chemotherapy for early disease, the use of taxanes as standard for advanced newly diagnosed patients, whether there is a definite role for neoadjuvant chemotherapy and the question of maintenance treatment. For relapsed disease, the management hinges around the distinction between platinum-sensitive and -resistant cancer, and the recent AGO-2.5 and ICON-4 studies suggest that treating with carboplatin and paclitaxel or carboplatin and gemcitabine is recommended. Intraperitoneal chemotherapy remains an enigma with at least three studies showing survival advantage; however, there has been no move to incorporate it into standard management of those patients who achieve complete remission after first-line chemotherapy. Finally, neoadjuvant chemotherapy prior to debulking surgery is the subject of several ongoing clinical trials and may turn out to be one of the most important developments since the concept of interval debulking surgery was established and proven in Europe.

Prognostic significance of p53 mutation in suboptimally resected advanced ovarian carcinoma treated with the combination chemotherapy of paclitaxel and carboplatin

The prognostic significance of p53 mutation, microsattelite instability and DNA mismatch protein hMLH1 expression in suboptimally resected advanced ovarian carcinoma treated with the combination chemotherapy of paclitaxel and carboplatin was evaluated. The overall combination chemotherapy response rate and the complete remission rate were significantly higher among patients with mutant p53 tumors than those with wild-type p53 tumors (35/42 (83%) vs. 32/58 (55%); P=0.003 and 18/42 (43%) vs. 16/58 (28%); P=0.03, respectively). This tendency apparently existed in non-serous carcinoma, but not in serous carcinoma. Univariate analysis showed that the risk of death due to disease and risk of progression was significantly lower among patients with p53 mutation (P=0.0357 and 0.0281, respectively). However, the presence of microsattelite instability or loss of hMLH1 expression was not associated with either the clinical response or prognosis. Determining p53 mutational status can be useful in predicting therapeutic response to drugs in ovarian carcinoma, especially in non-serous tumors.

Cytogenetic analysis of carboplatin resistance in early-stage epithelial ovarian carcinoma

Ovarian carcinoma is the leading cause of death among women with gynecological malignancies in western Europe. The high mortality rate is largely due to drug resistance. It is thus essential to increase knowledge and understanding of the underlying mechanisms of chemotherapy resistance, which might be caused by changes in the tumor genome. After surgery, carboplatin is the standard treatment for patients with early-stage ovarian cancer. Using comparative genomic hybridization (CGH), we explored cytogenetic alterations in 63 early-stage epithelial ovarian tumors, comparing the aberration patterns in the carboplatin-resistant and carboplatin-sensitive tumors. Several chromosomal regions were more frequently altered in the resistant tumors; some of these differences were statistically significant. We also found differences in tumor histology. Gains of 1q, 5q14 approximately q23, and 13q21 approximately q32, and losses of 8p and 9q were associated with clinical carboplatin resistance. Also, differences were found between the primary resistant and the secondary resistant tumors. Our findings demonstrate biologic observations of clinical drug resistance and specifically reveal chromosomal regions of interest for platinum resistance.

Frequent gene dosage alterations in stromal cells of epithelial ovarian carcinomas

Stromal cells are an active and integral part of epithelial neoplasms. We have previously observed allelic imbalance on chromosome 3p21 in both stromal and epithelial cells of ovarian tumors. This study was designed to explore gene dosage alterations throughout human chromosomes from stromal and epithelial cells of epithelial ovarian carcinomas. Thirteen stromal and 24 epithelial samples, microdissected from epithelial ovarian carcinomas, were analyzed using multiplex ligation-dependent probe amplification technique. Analysis covered 110 cancer related genes. Frequent genetic alterations were detected both in the stroma and epithelium of ovarian carcinomas. The mean number of altered genes per tumor was 10.8 in stroma and 23.6 in epithelium. In the stroma, the mean number of gains was 6.6 and of losses 4.2 and in the epithelium 13.7 and 9.9. The high number of changes associated with advanced tumor stage (p = 0.035) and death due to ovarian cancer (p = 0.032). The most frequent alteration was the deletion of the deleted in colorectal carcinoma (DCC) on chromosome 18q21.3 in 62% of samples. Loss of DCC was related to endometrioid subtype (p = 0.033). Large chromosomal aberrations were detected on the basis of alterations in adjacent genes. Most importantly, 38 genes showed similar genetic alterations (gain-gain or loss-loss) in stromal and epithelial compartments of 11 tumor pairs. Thus, frequent genetic alterations in stromal cells of epithelial ovarian carcinomas resembled those of malignant epithelial cells and may indicate a common precursor cell type. Epithelial-mesenchymal transition may generate transformed cancer cells and modify the tumor microenvironment with distinct properties.

Advanced stage mucinous epithelial ovarian cancer: the Hellenic Cooperative Oncology Group experience

OBJECTIVE

Mucinous epithelial ovarian cancer (mEOC) representing about 10% of all EOC are known to be possibly resistant to platinum-based chemotherapy and bear a poorer prognosis with respect to other subtypes of EOC. This study was undertaken to compare response and survival to platinum-based chemotherapy between patients with advanced stages III and IV mEOC and serous EOC (sEOC).

METHODS

A retrospective analysis was performed in 47 patients with advanced stage of mEOC treated with first-line platinum-based chemotherapy in the context of several study protocols of the Hellenic Cooperative Oncology Group (HeCOG) between 6/7/1983 and 25/2/2003. The outcome was compared to that of 94 patients with sEOC treated with the same protocols during the same study period (ratio mucinous: serous 1:2).

RESULTS

One hundred forty-one patients (47 stages III and IV mEOC, 94 stages III and IV sEOC) treated with platinum-based chemotherapy were analyzed. The overall response rate for mEOC was 38.5% (complete remission 18%) (95% CI 23.4-55.4%) and 70% (complete remission 47%) (95% CI 58.5-80.3%) for sEOC (P = 0.001). After a median follow-up of 77.8 months, median survival and time to tumor progression (TTP) were not significantly different between the two groups (33.2 months [95% CI 23.3-43.1 months] vs. 38.0 months [95% CI 26.8-49.2 months], P = 0.46, 11.8 months [95% CI 7.2-16.4 months] vs. 20.0 months [95% CI 15.7-24.2 months], P = 0.18, respectively).

CONCLUSION

Patients with mEOC have significantly lower response to first-line platinum-based chemotherapy compared to patients with sEOC. This low response to platinum-based chemotherapy was not translated in inferior TTP or survival. Our data indicate that a new strategy for chemotherapy in mEOC should be adopted, one that focuses on new agents without cross-resistance to platinum agents.

Expression of the tumor suppressor gene ARHI in epithelial ovarian cancer is associated with increased expression of p21WAF1/CIP1 and prolonged progression-free survival

PURPOSE

ARHI, an imprinted putative tumor suppressor gene, is expressed in normal ovarian epithelial cells, but its expression is down-regulated or lost in most ovarian cancer cell lines. Reexpression of ARHI in cancer cells induces p21(WAF1/CIP1), down-regulates cyclin D1 promoter activity and inhibits growth in cell culture and in heterografts. To determine the relevance of these observations to clinical cancer, we have now measured ARHI expression in normal, benign and malignant ovarian tissues using immunohistochemistry and in situ hybridization.

EXPERIMENTAL DESIGN

Paraffin embedded tissues from 7 normal ovaries, 22 cystadenomas and 42 borderline lesions were analyzed using standard immunoperoxidase and in situ hybridization techniques to assess ARHI expression. In addition, immunohistochemistry against ARHI was performed on a tissue microarray containing 441 consecutive cases of ovarian carcinoma.

RESULTS

Strong ARHI expression was found in normal ovarian surface epithelial cells, cysts and follicles using immunohistochemistry and in situ hybridization. Reduced ARHI expression was observed in tumors of low malignant potential as well as in invasive cancers. ARHI expression was down-regulated in 63% of invasive ovarian cancer specimens and could not be detected in 47%. When immunohistochemistry and in situ hybridization were compared, ARHI protein expression could be down-regulated in the presence of ARHI mRNA. ARHI expression was correlated with expression of p21(WAF1/CIP1) (P = 0.0074) but not with cyclin D1 and associated with prolonged disease free survival (P = 0.001). On multivariate analysis, ARHI expression, grade and stage were independent prognostic factors. ARHI expression did not correlate with overall survival.

CONCLUSIONS

Persistence of ARHI expression in epithelial ovarian cancers correlated with prolonged disease free survival and expression of the cyclin dependent kinase inhibitor p21(WAF1/CIP1).

Mucinous cystic carcinoma of the pancreas: a unique cell line and xenograft model of a preinvasive lesion

Pancreatic mucinous cystic tumors (MCT) are proliferations of mucin-producing epithelia supported by an ovarian-like stroma. They are classified into adenomas (MCA), borderline (MCB) and noninvasive or invasive carcinomas (MCC). The molecular mechanisms underlying their clinical behavior are poorly understood, partly due to the lack of cellular models. We report the establishment of MCC1, the first cell line from a pancreatic MCT, deriving from the highly dysplastic cell component of a noninvasive MCC. MCC1 has mutations in codon 12 of K-RAS (GGT>GAT), codon 58 of P16 (CGA>TGA) and codon 132 of P53 (AAG>AGG). The FHIT and DPC4 genes are unaltered. Immunohistochemistry shows abnormal expression of MUC1 and p53, loss of p16 and retention of Fhit and Dpc4 in both the cell line and the highly dysplastic cells of the primary lesion. The morphological and molecular features of MCC1 and its corresponding primary tumor are consistent with a model for non-invasive MCC, where K-RAS, P16, P53 and MUC1 alterations are pre-invasive changes associated with progression of malignancy of MCT from adenoma to carcinoma. MCC1 is sensitive to 5-fluorouracil, representing the first assessment of drug sensitivity for MCC. Finally, MCC1 is a suitable model for preclinical studies, as it grows in immunodeficient mice.

Endogenous Hormones and Ovarian Cancer: Epidemiology and Current Hypotheses

The effect of major epidemiologic risk factors for ovarian cancer has been reviewed in the light of several hormonal hypotheses, including the gonadotropin, androgens, progesterone, estrogens, insulin-like growth factor-I, and insulin hypotheses. The role of inclusion cyst formation and Mullerian epithelium differentiation in the pathology of the disease are also briefly outlined. Although based on limited data, the observed tendency in current evidence suggests possible etiologic roles for elevated androgens and estrogens and decreased progesterone in the pathogenesis of ovarian cancer. A direct effect of gonadotropins cannot be entirely ruled out, but it is plausible that their effect on ovarian cancer risk is mediated by stimulation of ovarian steroidogenesis. Insulin-like growth factor-I also emerges as a hormone that may be directly involved in the pathogenesis of the disease, but thus far only one prospective study has examined this association. Hyperinsulinemia is an unlikely risk factor for ovarian cancer. The observed tendency for an increased risk with androgens from ovarian origin (in premenopausal women), the lack of association with adrenal androgens, and the relatively weak associations observed with obesity, hormonal replacement therapy use, and endogenous hormones after menopause suggest that ovarian synthesis of sex steroids rather than their circulating levels may be etiologically important. More data from prospective studies will be crucial to improve our understanding of the etiologic role of endogenous hormones in the pathogenesis of ovarian cancer. Such data will ultimately provide opportunities for research targeted; at early detection and preventive interventions.

The epigenetics of ovarian cancer drug resistance and resensitization

Ovarian cancer is the most lethal of all gynecologic neoplasms. Early-stage malignancy is frequently asymptomatic and difficult to detect and thus, by the time of diagnosis, most women have advanced disease. Most of these patients, although initially responsive, eventually develop and succumb to drug-resistant metastases. The success of typical postsurgical regimens, usually a platinum/taxane combination, is limited by primary tumors being intrinsically refractory to treatment and initially responsive tumors becoming refractory to treatment, due to the emergence of drug-resistant tumor cells. This review highlights a prominent role for epigenetics, particularly aberrant DNA methylation and histone acetylation, in both intrinsic and acquired drug-resistance genetic pathways in ovarian cancer. Administration of therapies that reverse epigenetic "silencing" of tumor suppressors and other genes involved in drug response cascades could prove useful in the management of drug-resistant ovarian cancer patients. In this review, we summarize recent advances in the use of methyltransferase and histone deacetylase inhibitors and possible synergistic combinations of these to achieve maximal tumor suppressor gene re-expression. Moreover, when used in combination with conventional chemotherapeutic agents, epigenetic-based therapies may provide a means to resensitize ovarian tumors to the proven cytotoxic activities of conventional chemotherapeutics.

Chemosensitivity and radiosensitivity profiles of four new human epithelial ovarian cancer cell lines exhibiting genetic alterations in BRCA2, TGFbeta-RII, KRAS2, TP53 and/or CDNK2A

To address the cellular basis for the response to ovarian cancer treatment, we characterized the chemosensitivity and radiosensitivity of four human epithelial ovarian cancer cell lines that harbor different genetic alterations. The TOV-21G, TOV-81D, OV-90, and TOV-112D cell lines were derived from ovarian tumors (TOV) or ascites (OV) from chemotherapy- and radiotherapy-naive patients and were characterized by their mutation spectrum of BRCA2, TGFbeta-RII, KRAS2, TP53, and CDKN2A. Cells were monitored for survival following exposure at various concentrations to different cytotoxic agents including cisplatin, camptothecin or paclitaxel or to different doses of gamma-irradiation. At the lowest doses, the TGFbeta-RII-mutated and KRAS2-mutated cell line, TOV-21G, and the BRCA2-mutated cell line, TOV-81D, demonstrated a significantly higher sensitivity to cisplatin and gamma-irradiation than the TP53-mutated cell lines, TOV-112D and OV-90. At higher doses, differences between the TP53-mutated lines were observed with TOV-112D being less sensitive to cisplatin than OV-90 that also harbors a CDNK2A mutation. All cell lines were similarly sensitive to high doses of gamma-irradiation. In contrast, sensitivity to camptothecin or paclitaxel was not significantly different between all cell lines, irrespective of the mutation status of BRCA1, BRCA2, TGFbeta-RII, KRAS2, TP53, and CDKN2A. The observed responses to treatment are consistent with the current knowledge concerning BRCA2, TGFbeta-RII, KRAS2, TP53, and/or CDKN2A aberrant function.

Mucinous epithelial ovarian cancer: a separate entity requiring specific treatment

PURPOSE

Invasive mucinous carcinoma of the ovary (mucinous epithelial ovarian cancer [mEOC]) is a histologic subgroup of epithelial ovarian cancer (EOC). Chemotherapy for mEOC is chosen according to guidelines established for EOC. The purpose of this study is to determine whether this is appropriate.

PATIENTS AND METHODS

Women with advanced mEOC (International Federation of Gynecology and Obstetrics stage III or IV) who underwent first-line platinum-based chemotherapy were compared with women with other histologic subtypes of EOC in a case-controlled study.

RESULTS

Eighty-one patients (27 cases, 54 controls) treated with platinum-based regimens were analyzed. The response rates for cases and controls were 26.3% (95% CI, 9.2% to 51.2%) and 64.9% (95% CI, 47.5% to 79.8%), respectively (P=.01). The odds ratio for complete or partial response to chemotherapy for mEOC was 0.19 (95% CI, 0.06 to 0.66; P=.009) compared with other histologic subtypes of EOC. Median progression-free survival was 5.7 months (95% CI, 1.9 to 9.6 months) versus 14.1 months (95% CI, 12.0 to 16.2 months; P<.001) and overall survival was 12.0 months (95% CI, 8.0 to 15.6 months) versus 36.7 months (95% CI, 25.2 to 48.2 months; P<.001) for cases and controls, respectively. The hazard ratio for progression and death was 2.94 (95% CI, 1.71 to 5.07; P<.001) and 3.08 (95% CI, 1.69 to 5.6; P<.001), respectively, for mEOC patients as compared with controls.

CONCLUSION

Patients with advanced mEOC have a poorer response to platinum-based first-line chemotherapy compared with patients with other histologic subtypes of EOC, and their survival is worse. Specific alternative therapeutic approaches should be sought for this group of patients, perhaps involving fluorouracil-based chemotherapy.