Sporadic Epithelial Ovarian Cancer Research Articles

Immunohistochemical and molecular pattern of p53 in epithelial ovarian cancers negative for germline BRCA1/2 variants

Epithelial ovarian cancers (EOC) associated with germline or somatic BRCA pathogenetic variants have a significantly higher rate of TP53aberrations. The majority of TP53 mutations are detectable by immunohistochemistry and several studies demonstrated that an abnormal p53 pattern characterized high-grade EOCs. An abnormal p53 immunohistochemical staining in fallopian tube (serous tubal intraepithelial carcinoma (STIC) and “p53 signature” is considered as a precancerous lesion of high-grade EOCs and it is often found in fallopian tube tissues of BRCA germline mutated patients suggesting that STIC is an early lesion and the TP53 mutation is an early driver event of BRCA mutated high-grade EOCs. No relevant data are present in literature about the involvement of p53 abnormal pattern in EOC carcinogenesis of patients negative for germline BRCA variants. We describe TP53 mutation results in relationship to the immunohistochemical pattern of p53 expression in a series of EOCs negative for BRCA1 and BRCA2 germline mutations. In addition, we also investigated STIC presence and “p53 signature” in fallopian tube sampling of these EOCs. Our results demonstrate that TP53 alterations are frequent and early events in sporadic EOCs including also low-grade carcinomas. Also in this series, STIC is associated with an abnormal p53 pattern in fallopian tubes of high-grade EOCs. In summary, TP53 aberrations are the most frequent and early molecular events in EOC carcinogenesis independently from BRCA mutation status.

Progression-free survival and overall survival after BRCA1/2-associated epithelial ovarian cancer: A matched cohort study.

Germline BRCA1/2-associated epithelial ovarian cancer has been associated with better progression-free survival and overall survival than sporadic epithelial ovarian cancer, but conclusive data are lacking. We matched 389 BRCA1-associated and 123 BRCA2-associated epithelial ovarian cancer patients 1:1 to sporadic epithelial ovarian cancer patients on year of birth, year of diagnosis, and FIGO stage (< = IIA/> = IIB). Germline DNA test was performed before or after epithelial ovarian cancer diagnosis. All patients received chemotherapy. We used Cox proportional hazards models to estimate the associations between mutation status (BRCA1 or BRCA2 versus sporadic) and progression-free survival and overall survival. To investigate whether DNA testing after epithelial ovarian cancer diagnosis resulted in survival bias, we performed additional analyses limited to BRCA1/2-associated epithelial ovarian cancer patients with a DNA test result before cancer diagnosis (n = 73 BRCA1; n = 9 BRCA2) and their matched sporadic controls. The median follow-up was 4.4 years (range 0.1-30.1). During the first three years after epithelial ovarian cancer diagnosis, progression-free survival was better for BRCA1 (HR 0.88, 95% CI 0.74-1.04) and BRCA2 (HR 0.58, 95% CI 0.41-0.81) patients than for sporadic patients. Overall survival was better during the first six years after epithelial ovarian cancer for BRCA1 (HR 0.7, 95% CI 0.58-0.84) and BRCA2 (HR 0.41, 95% CI 0.29-0.59) patients. After surviving these years, survival benefits disappeared or were in favor of the sporadic patients. For epithelial ovarian cancer patients who received chemotherapy, we confirmed survival benefit for BRCA1 and BRCA2 germline pathogenic variant carriers. This may indicate higher sensitivity to chemotherapy, both in first line treatment and in the recurrent setting. The observed benefit appears to be limited to a relatively short period after epithelial ovarian cancer diagnosis.

Germline risk assessment and genetic counseling in ovarian cancer patients of diverse self-reported race/ethnicity and ancestry (388)

<b>Objectives:</b> To evaluate differences in rates of pathogenic/likely pathogenic germline variants (P/LPV) and subsequent genetic counseling by self-reported ancestry in epithelial ovarian cancer (EOC) patients (pts) undergoing tumor-normal sequencing for cancer care. <b>Methods:</b> EOC pts were prospectively consented to tumor-normal sequencing via a custom NGS panel (MSK-IMPACT) from January 2015 to December 2019, inclusive of germline analysis up to 88 genes. Designated EOC-associated genes included: <i>BRCA1 BRCA2, RAD51C, RAD51D, BRIP1, PALB2, ATM, MLH', MSH2, MSH6,</i> and <i>PMS2.</i> Variants of uncertain significance were not included. All women with new P/ LPV were referred to a Clinical Genetics Service (CGS) for counseling. Ancestry was defined using self-reported definitions of race/eth- nicity and designations of Ashkenazi Jewish (AJ) ancestry. Pts were categorized into mutually exclusive groups (AJ, Non-Hispanic [NH]- White, Non-White [Asian, Black/African American, Hispanic, other], or unknown). Patients identifying as AJ or Hispanic were classified as such, regardless of race. Clinical characteristics were analyzed using summary statistics. Associations between ancestry, mutation status, and CGS follow-up were assessed with non-parametric statistical tests (STATA V17). <b>Results:</b> Of 919 pts with EOC, 235 (25.6%) had a P/LPV, with 149 (16.2%) in an EOC-associated gene. Of those with P/LPV, 91 (38.7%) previously knew about this result for all genes, and 84 (56.4%) knew of this result for EOC-associated genes. For those with new findings, 80% presented for CGS counseling. The median age of EOC diagnosis for the entire cohort was 60 years (range: 16-90). Carriers of a P/LPV had a younger age at diagnosis compared with pts with sporadic EOC (59 vs 61, p=0.012). High-grade serous EOC (HGSOC) comprised 77% of cancers, and P/LPV carriers were more likely to have HGSOC than other histologies (85.5% vs 74.1%, p<0.001). Women were identified as NH-White (58%), AJ (17%), Asian (10%), Hispanic (6%), Black (5%) and unknown (4%) ancestries. The prevalence of P/LPV differed by ancestry for all genes (NH-White 22%, AJ 41%, Asian 28%, Hispanic 18%, Black 21%, unknown 21%, p<0.001). When assessing specifically for EOC-associated genes, a similar pattern was observed; AJ pts had the highest prevalence of P/LPV (25.6%). After removal of AJ pts, rates of EOC-associated P/LPV differed between NH-White (12%), Asian (25%), Hispanic (18%), and Black (21%) pts (p=0.021). There were no significant differences between ancestry groups in rates of prior knowledge of P/LPV or CGS follow-up rates for newly diagnosed pts with P/LPV. <b>Conclusions:</b> Rates of P/LPV, particularly in EOC-associated genes, were high in Non-White pts, particularly in Asian pts, compared with Non-AJ, NH-White pts. Rates of follow-up counseling were similar between ancestry groups. These findings highlight the need for universal genetic testing in all EOC pts regardless of ancestry, given the implications for treatment and cascade testing.

CAMK2N1/RUNX3 methylation is an independent prognostic biomarker for progression-free and overall survival of platinum-sensitive epithelial ovarian cancer patients

BackgroundTo date, no predictive or prognostic molecular biomarkers except BRCA mutations are clinically established for epithelial ovarian cancer (EOC) despite being the deadliest gynecological malignancy. Aim of this biomarker study was the analysis of DNA methylation biomarkers for their prognostic value independent from clinical variables in a heterogeneous cohort of 203 EOC patients from two university medical centers.ResultsThe marker combination CAMK2N1/RUNX3 exhibited a significant prognostic value for progression-free (PFS) and overall survival (OS) of sporadic platinum-sensitive EOC (n = 188) both in univariate Kaplan–Meier (LogRank p < 0.05) and multivariate Cox regression analysis (p < 0.05; hazard ratio HR = 1.587). KRT86 methylation showed a prognostic value only in univariate analysis because of an association with FIGO staging (Fisher’s exact test p < 0.01). Thus, it may represent a marker for EOC staging. Dichotomous prognostic values were observed for KATNAL2 methylation depending on BRCA aberrations. KATNAL2 methylation exhibited a negative prognostic value for PFS in sporadic EOC patients without BRCA1 methylation (HR 1.591, p = 0.012) but positive prognostic value in sporadic EOC with BRCA1 methylation (HR 0.332, p = 0.04) or BRCA-mutated EOC (HR 0.620, n.s.).ConclusionThe retrospective analysis of 188 sporadic platinum-sensitive EOC proved an independent prognostic value of the methylation marker combination CAMK2N1/RUNX3 for PFS and OS. If validated prospectively this combination may identify EOC patients with worse prognosis after standard therapy potentially benefiting from intensive follow-up, maintenance therapies or inclusion in therapeutic studies. The dichotomous prognostic value of KATNAL2 should be validated in larger sample sets of EOC.

DNA Methylation in Ovarian Cancer Susceptibility.

Simple SummaryIt is well established that ovarian cancer “runs in families”, where ovarian and other cancers (commonly breast cancer) occur at early ages at onset and in multiple generations. After decades of genetic studies, rare high-risk genetic mutations in cancer susceptibility genes and over 40 common genetic variants with much smaller risks have been identified. However, based on familial studies, we know that additional heritable genetic risk factors exist. It is possible that epigenetic variation—differences in how DNA is read, and which genes are actively expressed (or not) —also contributes to ovarian cancer susceptibility. This review summarizes the current collection of epidemiological studies that have investigated the role of DNA methylation—one type of epigenetic mechanism—in the risk of ovarian cancer.Epigenetic alterations are somatically acquired over the lifetime and during neoplastic transformation but may also be inherited as widespread ‘constitutional’ alterations in normal tissues that can cause cancer predisposition. Epithelial ovarian cancer (EOC) has an established genetic susceptibility and mounting epidemiological evidence demonstrates that DNA methylation (DNAm) intermediates as well as independently contributes to risk. Targeted studies of known EOC susceptibility genes (CSGs) indicate rare, constitutional BRCA1 promoter methylation increases familial and sporadic EOC risk. Blood-based epigenome-wide association studies (EWAS) for EOC have detected a total of 2846 differentially methylated probes (DMPs) with 71 genes replicated across studies despite significant heterogeneity. While EWAS detect both symptomatic and etiologic DMPs, adjustments and analytic techniques may enrich risk associations, as evidenced by the detection of dysregulated methylation of BNC2—a known CSG identified by genome-wide associations studies (GWAS). Integrative genetic–epigenetic approaches have mapped methylation quantitative trait loci (meQTL) to EOC risk, revealing DNAm variations that are associated with nine GWAS loci and, further, one novel risk locus. Increasing efforts to mapping epigenome variation across populations and cell types will be key to decoding both the genomic and epigenomic causal pathways to EOC.

RAD50 deficiency is a predictor of platinum sensitivity in sporadic epithelial ovarian cancers

Intrinsic or acquired resistance seriously limits the use of platinating agents in advanced epithelial ovarian cancers. Increased DNA repair capacity is a key route to platinum resistance. RAD50 is a critical component of the MRN complex, a ‘first responder’ to DNA damage and essential for the repair of DSBs and stalled replication forks. We hypothesised a role for RAD50 in ovarian cancer pathogenesis and therapeutics. Clinicopathological significance of RAD50 expression was evaluated in clinical cohorts of ovarian cancer at the protein level (n = 331) and at the transcriptomic level (n = 1259). Sub-cellular localization of RAD50 at baseline and following cisplatin therapy was tested in platinum resistant (A2780cis, PEO4) and sensitive (A2780, PEO1) ovarian cancer cells. RAD50 was depleted and cisplatin sensitivity was investigated in A2780cis and PEO4 cells. RAD50 deficiency was associated with better progression free survival (PFS) at the protein (p = 0.006) and transcriptomic level (p < 0.001). Basal level of RAD50 was higher in platinum resistant cells. Following cisplatin treatment, increased nuclear localization of RAD50 was evident in A2780cis and PEO4 compared to A2780 and PEO1 cells. RAD50 depletion using siRNAs in A2780cis and PEO4 cells increased cisplatin cytotoxicity, which was associated with accumulation of DSBs, S-phase cell cycle arrest and increased apoptosis. We provide evidence that RAD50 deficiency is a predictor of platinum sensitivity. RAD50 expression-based stratification and personalization could be viable clinical strategy in ovarian cancers.

PARP1 blockade is synthetically lethal in XRCC1 deficient sporadic epithelial ovarian cancers.

PARP1 inhibitor (Niraparib, Olaparib, Rucaparib) maintenance therapy improves progression-free survival in platinum sensitive sporadic epithelial ovarian cancers. However, biomarkers of response to PARPi therapy is yet to be clearly defined. XRCC1, a scaffolding protein, interacts with PARP1 during BER and SSBR. In a large clinical cohort of 525 sporadic ovarian cancers, high XRCC1 or high PARP1 protein levels was not only associated with aggressive phenotypes but was also significantly linked with poor progression-free survival (p = 0.048 & p = 0.001 respectively) and poor ovarian cancer-specific survival (p = 0.020 & p = 0.008 respectively). Pre-clinically, Olaparib and Talazoparib therapy were selectively toxic in XRCC1 deficient or knock-out platinum sensitive ovarian cancer cells in 2D and 3D models. Increased sensitivity was associated with DNA double-strand break accumulation, cell cycle arrest and apoptotic cell accumulation. We conclude that XRCC1 deficiency predicts sensitivity to PARP inhibitor therapy. PARP1 targeting is a promising new approach in XRCC1 deficient ovarian cancers.

Epithelial ovarian cancer and type of peritoneal insult: a case–control study

ObjectiveTo evaluate the association between different types of peritoneal insults and the development of sporadic epithelial ovarian cancer (EOC) subtypes in the general population. Study designHospital based case control study comparing sporadic cases of EOC with age matched control group between 2003 and 2008. Medical, surgical, and gynecological histories were compared between 208 women with histological diagnosis of EOC and 224 women in the control group matched for age at presentation for well woman examination. Results18% patients in the study population and 5% patients in the control group had history of diverticulosis (OR 7.3, 95% CI 2.8–19.1). 10% patients in the study populations and 39% patients in the control group had history of diabetes mellitus (OR 0.41, 95% CI 0.23–0.75). Sub classification of EOC into type 1 and type 2 further revealed 12% patients (OR 0.44, 95% CI 0.22–0.87) in type 1 group, 35% patients (OR 0.43, 95% CI 0.27–0.69) in type 2 group, and 71% patients in the control group had no prior surgical history. Furthermore, 3% patients (OR 0.27; 95% CI 0.08–0.9) in the type 1 group, 48% patients (OR 2.0, CI 95% 1.24–3.24) in the type 2 group, and 41% patients in the control group had history of bilateral tubal ligation (BTL). ConclusionA significant association was found between diverticulosis, hysterectomy and endometriosis increasing the likelihood of type 1 EOC; while diverticulosis, exploratory laparotomy and hysterectomy increased the likelihood of type 2 EOC. BTL was significantly associated with decreasing the likelihood of type 1 EOC, but increasing the likelihood of type 2 EOC. Diabetes mellitus and no prior surgical history were found to significantly decrease the likelihood of all EOC.

Germline mutations of BRCA1 gene exon 11 are not associated with platinum response neither with survival advantage in patients with primary ovarian cancer: understanding the clinical importance of one of the biggest human exons. A study of the Tumor Bank Ovarian Cancer (TOC) Consortium.

Germline mutations in BRCA1 gene have been reported in up to 20% of epithelial ovarian cancer (EOC) patients. Distinct clinical characteristics have been attributed to this special EOC population. We hypothesized that mutations in different BRCA1 gene exons may differently affect the clinical course of the disease. The aim of this study was to analyze, in a large cohort of primary EOCs, the clinical impact of mutations in BRCA1 gene exon 11, the largest exon of the gene sequence encoding the 60% of BRCA1 protein. Two hundred sixty-three primary EOC patients, treated between 2000 and 2008 at Charité University Hospital of Berlin, were included. Patients' blood samples were obtained from the Tumor Ovarian Cancer (TOC) Network ( www.toc-network.de ). Direct sequencing of BRCA1 gene exon 11 was performed for each patient to detect mutations. Based on their BRCA1 exon 11 mutational status, patients were compared regarding clinico-pathological variables and survival. Mutations in BRCA1 exon 11 were found in 18 out of 263 patients (6.8%). Further 10/263 (3.8%) cases showed variants of uncertain significance (VUS). All exon 11 BRCA1-positive tumors (100%) were Type 2 ovarian carcinomas (p = 0.05). Age at diagnosis was significantly younger in Type 2 exon 11 mutated patients (p = 0.01). On multivariate analysis, BRCA1 exon 11 mutational status was not found to be an independent predictive factor for optimal cytoreduction, platinum response, or survival. Mutations in BRCA1 gene exon 11 seem to predispose women to exclusively develop a Type 2 ovarian cancer at younger age. Exon 11 BRCA1-mutated EOC patients showed distinct clinico-pathological features but similar clinical outcome with respect to sporadic EOC patients.

Abstract 4251: Paclitaxel is necessary for improved survival in epithelial ovarian cancers with somatic homologous recombination gene mutations

Abstract The impact of somatic mutations and genomic alterations in determining the clinical outcome of sporadic epithelial ovarian cancer (EOC) remains uncertain. Our goal was to identify molecular markers of optimal cytoreduction, chemotherapeutic response, and survival. We focused on genes in the homologous recombination (HR) DNA repair pathway, as germline mutations in these genes confer improved survival, and data suggest that somatic mutations may similarly predict improved survival and chemosensitivity. One hundred fifty-eight patients were included with diagnoses of serous, endometrioid, or clear cell EOC and underwent primary cytoreduction followed by platinum-based chemotherapy. We performed targeted massively parallel sequencing of 53 genes in known genes from pathways such as HR and checkpoint inhibition in primary surgical samples. Patients were treated with platinum and cyclophosphamide (n = 24) or platinum and paclitaxel (n = 67). We detected 226 deleterious variants in 35 distinct genes. TP53 mutations were found in tumors from 90 subjects (56%) and deleterious mutations in HR genes in 45 (28%). Twenty-three patient tumors (15%) were found to have homozygous copy number loss of genes in the HR pathway. We did not detect an overall survival (OS) benefit in advanced stage patients treated with platinum whose tumors had HR mutations/loss as compared to those without HR defects. However, OS was significantly different between patients (p = 0.0028) whose tumors had HR mutations/loss if they received cyclophosphamide (median 24.1 months) as compared to paclitaxel (median 50.4 months). Furthermore, in patients with both TP53 and HR gene mutations or deletions, median OS improved to 76.6 months in the platinum and paclitaxel treated cohort (p = 0.0001). In this analysis by chemotherapy regimen and mutation status, the patients with TP53 and HR mutation/loss demonstrated worse median OS than those without such defects when treated with platinum and cyclophosphamide (24.1 months vs. 32.7 months respectively), but improved survival over patients without TP53 and HR defects when treated with platinum and paclitaxel (76.6 months vs. 44.4 months respectively, p = 0.0100). We also found that a somatic HR mutation was significantly associated with suboptimal debulking status (p = 0.012). Chances for optimal debulking and early stage were significantly increased in patients with PTEN mutations (p = 0.042), leading to OS benefit. The survival benefit attributed to platinum agents in HR deficient ovarian cancers may depend upon the use of paclitaxel in addition to platinum. This merits elucidation of the mechanism, and may be due to the mitosis cell cycle specificity of paclitaxel, and ensuing inhibition of HR deficient genomically unstable tumor subclones. Citation Format: Stephanie Jean, Bradley Wubbenhorst, Jiaqi Li, Kara N. Maxwell, Lauren Fishbein, Michael W. McLane, Nandita Mitra, Lin Zhang, Katherine L. Nathanson, Janos L. Tanyi. Paclitaxel is necessary for improved survival in epithelial ovarian cancers with somatic homologous recombination gene mutations. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4251. doi:10.1158/1538-7445.AM2015-4251

BRCA1 promoter methylation is a marker of better response to platinum-taxane-based therapy in sporadic epithelial ovarian cancer.

The aim of the current study was to investigate the role of BRCA1 promoter methylation as predictive factor of response to platinum-taxane-based therapy in sporadic ovarian cancer. BRCA1 promoter methylation was analyzed in 42 sporadic epithelial ovarian cancers. The results were validated in a second cohort of 137 ovarian cancer patients. BRCA1 promoter methylation was observed in 35.7% of patients in the first group and in 33.6% in the second group. BRCA1 promoter methylation was associated with significant increase in median progression-free survival (PFS) of ovarian cancer patients receiving adjuvant platinum-taxane-based chemotherapy (P=0.008). Multivariate analysis revealed that BRCA1 promoter methylation remains a favorable factor in regard to PFS (HR 0.52; 95% CI 0.32-0.85, P=0.009) after adjustment for other prognostic factors. Under the patients with recurrent disease, BRCA1 promoter methylation was associated with significant longer median PFS of 18.5months in comparison with 12.8months PFS for patients without BRCA1 promoter methylation. BRCA1 promoter methylation is predictive for better response to platinum-taxane-based therapy in EOC.

BRCA1 Expression Is Epigenetically Repressed in Sporadic Ovarian Cancer Cells by Overexpression of C-Terminal Binding Protein 2

INTRODUCTION: Ovarian cancer is the leading cause of mortality from gynecological malignancy despite advancements in novel therapeutics. We have recently demonstrated that the transcriptional co-repressor C-terminal binding protein 2 (CtBP2) is overexpressed in epithelial ovarian carcinoma. MATERIALS AND METHODS: Reverse-transcribed cDNA from CtBP2 wild-type and knockdown ovarian cancer cell lines was hybridized to Affymetrix Gene 1.0 ST microarrays, and differentially expressed genes were studied. Immunohistochemical analysis of CtBP2 and BRCA1 staining of ovarian tissues was performed. Chromatin immunoprecipitation (ChIP) and luciferase assays were carried out. The effect of the drugs 4-methylthio-2-oxobutyric acid (MTOB) and poly(ADP-ribose) polymerase (PARP) inhibitor Olaparib on CtBP2 wild-type and knockdown cell lines was examined using methylthiazol tetrazolium assays and an xCELLigence System. RESULTS: Eighty-five genes involved in DNA repair, mitotic checkpoint, nucleosome assembly, and the BRCA1 network were differentially regulated by CtBP2 expression. ChIP and luciferase reporter assays using a BRCA1 promoter-regulated luciferase construct indicated that the CtBP2 complex binds the BRCA1 promoter and represses BRCA1 transcription. Immunohistochemistry illustrated a significant inverse CtBP2 and BRCA1 expression in a panel of malignant ovarian tumor tissues. The CtBP2 inhibitor MTOB suppressed ovarian cancer cell survival in a CtBP2-dependent manner. Ovarian cancer cells with CtBP2 knockdown did not display increased sensitivity to the PARP inhibitor Olaparib. CONCLUSION: CtBP2 is an ovarian cancer oncogene that may play a significant role in epigenetically silencing BRCA1 function in sporadic epithelial ovarian cancer. CtBP2-specific inhibitors, such as MTOB, may be effective adjunct therapies in the management of patients with CtBP2-positive ovarian carcinoma.

Abstract 3054: Expression of miR367* confers a “BRCAness” phenotype in epithelial ovarian cancer.

Abstract Patients with hereditary epithelial ovarian cancer (EOC) associated with germline BRCA1/2 mutations exhibit improved outcome and high sensitivity to platinum and poly (ADP-ribose) polymerase inhibitors (PARPis) due to an underlying defect in DNA repair via homologous recombination (HR). Importantly, a subset of patients with sporadic EOCs also exhibit improved outcome and responsiveness to these cytotoxic agents - a phenotype commonly referred to as "BRCAness" - possibly due to defective HR caused by mechanisms unrelated to germline mutation in BRCA-1 or 2. Here, we report that expression of miR-367* in EOC tumors without genetic or epigenetic alterations of HR pathway genes is associated with a “BRCAness” phenotype. We accessed data from 313 high grade serous EOCs included in The Cancer Genome Atlas (TCGA) EOC dataset. For all these tumors gene expression, DNA copy number, promoter methylation and whole-exome DNA sequencing information was available. Approximately 50% of these tumors (154 of 313) had known genetic or epigenetic alterations in HR pathway genes, including somatic or germline BRCA1/2 mutations, hypermethylation of BRCA1 or RAD51C, amplification or mutation of EMSY, focal deletion or mutation of PTEN, mutation of ATM or ATR, and mutation of Fanconi anemia genes. We focused on the remaining 159 tumors that did not harbor genetic or epigenetic alterations in HR pathway and used miRNA Agilent array expression data from these tumors to correlate expression of miR-367* with outcome and platinum sensitivity. Among these 159 tumors without known genetic or epigenetic alterations of HR pathway genes, those tumors whose expression level for miR-367* was in the top tertile, were associated with improved overall survival (OS) and progression free survival (PFS), (hazard ratio for death was 0.604, p=0.033 and for progression was 0.599, p=0.025). Similar associations with OS and PFS were identified when miR-367* expression was evaluated as a continuous variable (p=0.013 for OS and p=0.029 for PFS). Furthermore, among these 159 tumors without known genetic or epigenetic alterations of HR pathway genes, those tumors whose expression level for miR-367* was in the top tertile were more likely to be platinum sensitive (71% vs 50% respectively, two sided p=0.069). Finally, induced expression of miR-367* in ovarian cancer cell lines enhanced sensitivity to DNA double strand break-inducing agents, such as carboplatin and the PARPi olaparib in vitro. These data suggest that expression of miR-367* is associated with a “BRCAness” phenotype in EOC, i.e. improved outcome and sensitivity to platinum and PARPis. We are currently investigating whether miR-367* may interfere directly with DNA repair via HR in vitro. Citation Format: Alexander Morse, Chiara Battelli, Hai Hu, Elena Levantini, Gerburg Wulf, Youngeun Choi, Dipanjan Chowdhury, Panagiotis Konstantinopoulos. Expression of miR367* confers a “BRCAness” phenotype in epithelial ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3054. doi:10.1158/1538-7445.AM2013-3054

Poly (ADP-ribose) polymerase inhibitors

Management of the epithelial ovarian cancer (EOC) remains a therapeutic challenge, with continued poor overall survival (OS). Given low chemotherapy response rates for recurrent disease and short survival times, new treatment options with improved therapeutic indices for targeting cancer's vulnerability are urgently needed in this patient population. In this review, we summarize the recent development and clinical evaluations of inhibitors of poly (ADP-ribose) polymerase (PARP) as novel targeting agents for EOC. PARP inhibitors exploit synthetic lethality to target DNA repair defects in hereditary breast and ovarian cancer.In recent clinical trials, EOC patients with BRCA mutations exhibited favorable responses to the PARP inhibitor olaparib compared with patients without BRCA mutations. Additionally, olaparib has been reported to augment the effects of cisplatin and carboplatin on recurrence-free survival and OS in mice bearing BRCA1/2-deficient tumors.Given that hereditary EOC with deleterious BRCA1/2 mutations and BRCAness sporadic EOC are profoundly susceptible to synthetic lethality with PARP inhibition, it is imperative to identify a population of EOC patients that is likely to respond to PARP inhibitors. Recent studies have identified the gene expression profiles of DNA repair defects and BRCAness that predict clinical outcomes and response to platinum-based chemotherapy in EOC patients. Ovarian cancer continues to carry the highest mortality among gynecologic cancers in the western world. Clinical development of PARP inhibitors that target DNA repair defects in cancer is a novel and imperative stride in individualized identification of molecular characteristics in management of ovarian cancer.

Clinicopathological Significance and Prognostic Value of DNA Methyltransferase 1, 3a, and 3b Expressions in Sporadic Epithelial Ovarian Cancer

Altered DNA methylation of tumor suppressor gene promoters plays a role in human carcinogenesis and DNA methyltransferases (DNMTs) are responsible for it. This study aimed to determine aberrant expression of DNMT1, DNMT3a, and DNMT3b in benign and malignant ovarian tumor tissues for their association with clinicopathological significance and prognostic value. A total of 142 ovarian cancers and 44 benign ovarian tumors were recruited for immunohistochemical analysis of their expression. The data showed that expression of DNMT1, DNMT3a, and DNMT3b was observed in 76 (53.5%), 92 (64.8%) and 79 (55.6%) of 142 cases of ovarian cancer tissues, respectively. Of the serious tumors, DNMT3a protein expression was significantly higher than that in benign tumor samples (P = 0.001); DNMT3b was marginally significant down regulated in ovarian cancers compared to that of the benign tumors (P = 0.054); DNMT1 expression has no statistical difference between ovarian cancers and benign tumor tissues (P = 0.837). Of the mucious tumors, the expression of DNMT3a, DNMT3b, and DNMT1 was not different between malignant and benign tumors. Moreover, DNMT1 expression was associated with DNMT3b expression (P = 0.020, r = 0.195). DNMT1 expression was associated with age of the patients, menopause status, and tumor localization, while DNMT3a expression was associated with histological types and serum CA125 levels and DNMT3b expression was associated with lymph node metastasis. In addition, patients with DNMT1 or DNMT3b expression had a trend of better survival than those with negative expression. Co-expression of DNMT1 and DNMT3b was significantly associated with better overall survival (P = 0.014). The data from this study provided the first evidence for differential expression of DNMTs proteins in ovarian cancer tissues and their associations with clinicopathological and survival data in sporadic ovarian cancer patients.

Abstract 2981: Association of a BRCAness profile with outcome and molecular aberrations involving homologous recombination in the TCGA ovarian cancer dataset

Abstract A subset of sporadic epithelial ovarian cancer (EOCs) may harbor a “BRCAness” phenotype characterized by improved outcome and enhanced responsiveness to platinum analogues and PARP inhibitors, similar to their BRCA1/2 mutated counterparts. This BRCAness phenotype may be due, in part, to defective homologous recombination (HR) related to various mechanisms, including BRCA1 promoter hypermethylation, somatic mutation of BRCA1/2 genes, or loss of function mutations in other HR pathway genes. We recently defined a gene expression profile of BRCAness that correlates with chemotherapy response and outcome in EOC. Here, we used The Cancer Genome Atlas (TCGA) EOC dataset to evaluate the association of the BRCAness profile with outcome, chemotherapy response and specific molecular aberrations that may underlie defective HR. We accessed data from 265 advanced stage high grade serous EOCs for which there was available gene expression, DNA copy number, promoter methylation and whole-exome DNA sequencing information. Patients were characterized as having a BRCAness phenotype (BL profile) or not (NBL profile) based on our BRCAness signature. BL patients were associated with improved median overall survival (OS) compared to NBL patients (59 vs 41 months respectively, log-rank p=0.008). Multivariable analysis demonstrated that the BRCAness profile maintained an independent association with OS (HR=1.72, p=0.024). BL patients had a longer median platinum free interval compared to NBL patients (17 vs 11 months, p=0.024) and improved median disease free survival (18 vs 14 months, p=0.055). BRCAness profile was associated with molecular events affecting BRCA1/2 function such as BRCA1/2 mutations, BRCA1 promoter hypermethylation and EMSY amplification (47% in BL patients vs 27% in NBL patients, two-sided Fisher's exact p=0.007). Furthermore, BL patients had higher frequency of homozygous PTEN deletion compared to NBL patients but this did not reach statistical significance (12% vs 6% respectively, two-sided Fisher's exact p=0.14). Conversely, BRCAness profile was not associated with molecular events affecting the function of other Fanconi Anemia (FA) genes (FANCA/B/C/D2/E/F/G/I/J/L/M, PALB2) or DNA damage response genes involved in HR (ATM, ATR, CHEK1, CHEK2) although the overall incidence of these molecular events was very low (5% and 3% respectively). In conclusion, the BRCAness profile may identify patients with improved outcome, responsiveness to chemotherapy, and those who harbor certain molecular aberrations involving HR. Efforts to improve the predictive ability of the BRCAness profile using gene expression data from the TCGA dataset are underway. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2981. doi:1538-7445.AM2012-2981

Clinical characteristics and outcomes of BRCA-associated ovarian cancer: genotype and survival

Previous studies have suggested that BRCA-related epithelial ovarian cancer (EOC) conveys improved survival compared with that of sporadic EOC, but few studies have evaluated differences between BRCA genotypes. We compared characteristics and outcome by genotype in BRCA-associated EOC. Patients with BRCA-associated EOC who were diagnosed between January 30,1981, and December 30, 2008, were retrospectively identified through institutional review board-approved registry studies. We examined clinical characteristics, including event-free survival (EFS) and overall survival (OS), for BRCA1 versus BRCA2 patients. We identified 197 cases (148 BRCA1 cases; 49 BRCA2 cases); the median follow-up period was 63 months. BRCA2 patients were older (55.4 vs. 51.1 y; P < 0.01) and had fewer poorly differentiated tumors (67% vs. 82%; P < 0.05). No difference in EFS was observed. OS at 5 years was 75% in BRCA2 patients versus 61% in BRCA1 patients; this was not statistically significant. A non-significant trend toward improved OS was observed in BRCA2 patients with advanced-stage disease (hazard ratio = 0.59; 95% confidence interval 0.32-1.08). Age and grade differed significantly between BRCA1 and BRCA2 carriers in our study population. Whereas no overall differences in EFS or OS were observed, there was a trend toward improved OS in BRCA2 carriers with advanced-stage disease. This may reflect important differences between BRCA genotypes and should be validated in larger studies.

Loss of BRCA1 Protein Expression as Indicator of the BRCAness Phenotype Is Associated With Favorable Overall Survival After Complete Resection of Sporadic Ovarian Cancer

Hereditary epithelial ovarian cancers (EOCs) not expressing functional BRCA1 protein are characterized by defects in homologous recombination DNA repair, rendering such tumors more sensitive to DNA damaging agents and synthetic lethality, that is, poly-ADP-ribose-polymerase inhibitor treatment. The aim of this study was to evaluate the use of BRCA1 immunohistochemistry (IHC) for EOC prognosis and identification of features of the BRCAness phenotype. Twenty-seven patients who were treated for advanced EOC by macroscopic complete surgical tumor resection and first-line carboplatin/paclitaxel treatment were included. Time to recurrence and overall survival time after initial surgery were determined, and patients' samples were evaluated for BRCA1 expression by IHC. BRCA1 messenger RNA expression and promoter methylation was analyzed to elucidate regulatory mechanisms involved in BRCA1 protein loss. BRCA1 IHC-negative patients had a significantly longer overall survival (crude rate, 1537 days) compared to the BRCA1 IHC-positive group (crude rate, 827 days; P = 0.01). The patients in the BRCA1 IHC-negative group were significantly younger (51 years) compared to BRCA1 IHC-positive patients (61 years; P < 0.01). Importantly, both transcriptional and posttranscriptional mechanisms regulate BRCA1 protein expression. Only protein but not messenger RNA level were associated with longer overall survival. Epithelial ovarian cancers with negative BRCA1 protein expression were identified in younger patients, showed a significantly better overall survival, prolonged treatment intervals and a tendency for an extended progression free time interval. BRCA1 IHC negativity of sporadic EOC may be predictive of sensitivity to platinum-based chemotherapy and the poly-ADP-ribose-polymerase inhibitor-sensitive BRCAness phenotype.

Functional Polymorphisms of the hOGG1 Gene Confer Risk to Type 2 Epithelial Ovarian Cancer in Chinese

8-Hydroxydeoxyguanosine (8-OHdG) is an oxidized nucleoside that can lead to misincorporation of bases. Human 8-oxoguanine DNA glycosylase (hOGG1) is the key defense enzyme against mutation by the cellular 8-OHdG in duplex DNA. The present study was aimed to explore whether the hOGG1 gene variants play an important role in the carcinogenesis of epithelial ovarian cancer (EOC). Germ line variants in 5'-untranslated region (c.-18G>T, c.-23A>G, c.-45G>A, and c.-53G>C) and c.977C>G (Ser326Cys) polymorphism in exon7 of the hOGG1 gene in 420 sporadic EOCs and 840 controls were detected. Immunohistochemical and promoter luciferase activity assays were used to explore the effect of c.-18G>T variant on hOGG1 expression. In contrast to type I EOC cases, patients with type II EOC were usually older, already in the advanced stage, and exhibited a common protein 53 (p53) overexpression. The frequencies of genotypes c.-18G/T and c.977G/G in hOGG1 were significantly high in the patients with type II EOC (odds ratio, 2.83; 95% confidence interval, 1.45-5.52; odds ratio, 1.66; 95% confidence interval, 1.26-2.17) but not in the patients with type I EOC. The average level of hOGG1 protein in the normal tissues adjacent to the type II EOC-carried c.-18G/T was lower than that with c.-18G/G (P = 0.01). The luciferase activity in the c.-18T allele was lower than that in the c.-18G allele (P = 0.001). The genotypes of c.-18G/T in 5'-untranslated region and c.977G/G in exon7 of the hOGG1 gene would confer risk to type II EOC.

BRCA1 is both a prognostic and predictive biomarker of response to chemotherapy in sporadic epithelial ovarian cancer

Objectives We investigated the relationship between BRCA1 protein expression by immunohistochemistry (IHC) and clinical outcome following platinum and platinum/taxane chemotherapy in sporadic epithelial ovarian cancer (EOC). Methods BRCA1 IHC was performed on a cohort of 292 ovarian tumours from two UK oncology centres. BRCA1 protein expression levels were correlated with overall survival (OS), progression free survival (PFS) and clinical response to chemotherapy by multivariate analysis. Results EOC patients with absent/low BRCA1 protein expression (41%) had a better chance of clinical response following chemotherapy as compared to patients with high BRCA1 expression (odds ratio 2.47: 95%CI 1.10–5.55, p = 0.029). Patients with absent/low BRCA1 had a higher probability of clinical response following single agent platinum compared to high BRCA1 expressing patients (68.5% vs. 46.8%), while addition of a taxane increased response rates independent of BRCA1. Overall, patients with absent/low BRCA1 had a better clinical outcome compared to patients with high BRCA1 protein expression in terms of both OS (HR = 0.65: 95%CI 0.48–0.88, p = 0.006) and PFS (HR = 0.74, 95%CI 0.55–0.98, p = 0.040). Conclusions We confirm that absent/low BRCA1 protein expression is a favourable prognostic marker. However, we also provide the first evidence that absent/low BRCA1 protein expression in sporadic EOC patients predicts for an improved clinical response to chemotherapy.