Serous Epithelial Ovarian Cancer Research Articles

Abstract CT124: First-in-human study of SC-004, an antibody-drug conjugate targeting CLDN6/9, in patients with epithelial ovarian cancers

Abstract Background: More than 90% of ovarian cancers are epithelial ovarian cancers (EOC), and approximately 70% of EOCs are serous histology. Despite advancements with the development of PARP inhibitors and incorporation of bevacizumab, a clear unmet need remains for patients (pts) with recurrent EOC which is no longer considered appropriate for platinum-based chemotherapy (platinum-resistant). Endometrial cancer (EC) is the most common gynecologic malignancy in the United States, and there are limited options for pts who progress after first and/or second line chemotherapy. Claudins (CLDNs) are four-pass transmembrane proteins with key roles in tight junction formation and function, regulation of paracellular transport, and maintenance of cell polarity. CLDN6 and CLDN9 are expressed on neoplastic cells in a proportion of high-grade EOC and high-grade serous EC with minimal expression in normal tissues. SC-004 is an antibody-drug conjugate (ADC), consisting of an antibody targeting CLDN6/9 linked to a pyrrolobenzodiazepine (PBD) dimer DNA cross-linking agent. In this open-label, phase 1 clinical trial, the safety, tolerability and maximum tolerated dose (MTD) of SC-004 were assessed in pts with platinum-resistant/refractory EOC and EC (NCT03138408). Methods: Enrolled pts were adults with platinum-refractory or resistant high-grade serous EOC or EC, who had previously received at least 1 platinum-based chemotherapeutic regimen. SC-004 was administered intravenously at 0.005-0.3 mg/kg every 3 weeks (0.3 mg/kg was administered every 4 weeks). Treatment emergent adverse events (TEAEs) were defined as any adverse event (AE) that worsened from the first dose of SC-004 through 90 days following discontinuation of treatment. Membranous CLDN6 expression was assessed by immunohistochemistry retrospectively. Results: A total of 24 pts were enrolled (11 with ovarian and 13 with EC). Pts received SC-004 for a median of 2.5 cycles (range:1-25). The most common TEAEs (>20% of pts, N=24) were fatigue (38%), peripheral edema (33%), vomiting (33%), pleural effusion (25%), urinary tract infection (25%), rash maculo-papular (25%), anemia (21%), abdominal pain (21%), diarrhea (21%), and decreased appetite (21%). Twenty-one pts (88%) had at least 1 AE possibly related to SC-004. Eight pts (33%) had at least 1 grade 3 or higher AE with a possibility of being related to SC-004, the most common being pericardial effusion in 2 pts (8%). Eight pts (33%) had at least 1 SAE, including pericardial effusion, pleural effusion, renal failure, respiratory failure, abdominal pain, and failure to thrive, each occurring in 2 pts (8%) each. Eight pts (33%) had at least 1 AE leading to SC-004 dose interruption. Three pts (13%) had a fatal AE considered unrelated to SC-004. Thirteen pts (54%) died during the trial, mainly due to disease progression. The MTD was 0.2 mg/kg Q3W. Among 19 evaluable pts, best overall response of stable disease occurred in 14 pts (73%), partial response in 1 pt (5%), and progressive disease in 4 pts (21%). 4/19 pts (21%) with evaluable tissue had at least 50% of tumor cells with membranous CLDN6 expression, and one of these pts had the only partial response. Conclusion: SC-004 demonstrated low tolerability with a side effect profile similar to other PBD-conjugated ADCs, along with insufficient evidence of activity to support continued investigation. Citation Format: Erika Hamilton, Gini F. Fleming, Premal H. Thaker, Vivek Subbiah, Chris Chen, Abraham Fong, Daniel Brickman, Kathleen Moore. First-in-human study of SC-004, an antibody-drug conjugate targeting CLDN6/9, in patients with epithelial ovarian cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT124.

Chemotherapy is not necessary for early-stage serous and endometrioid ovarian cancer after undergoing comprehensive staging surgery

In order to investigate whether adjuvant chemotherapy is essential for patients with early-stage serous and endometrioid epithelial ovarian cancer, the present study collected data from the US Surveillance, Epidemiology and End Results database between 2004 and 2015. All subjects underwent comprehensive staging surgery and were diagnosed as stages IA-IIA, grade 1–2. A total of 2644 patients were enrolled in the present study, among which 1589 patients received platinum-based chemotherapy. Comparisons of categorical data were performed via χ2 tests. Variables with P < 0.05 in univariate analyses were further analyzed using multiple logistic regression. Selection bias from the heterogeneity of demographic and clinical characteristics was avoided using propensity score matching. Cox proportional hazards models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), investigating the association between variables and 5-year overall survival. After the propensity score matching, there was an equal number of patients with or without chemotherapy (n = 925). The results of the present study indicated that those aged ≥65 years were at an increased risk of ovarian cancer, and the age was associated with poor prognosis (HR, 1.486; CI, 1.208–1.827; P < 0.001). Endometrioid carcinoma was associated with improved 5-year overall survival compared with serous cystadenocarcinoma (HR, 0.697; CI, 0.584–0.833; P < 0.001). Chemotherapy could not prolong the 5-year overall survival of patients with early-stage serous and endometrioid ovarian cancer (HR, 1.092; CI, 0.954–1.249; P = 0.201). These results demonstrated that adjuvant chemotherapy was unnecessary for patients with early-stage serous and endometrioid ovarian cancer after they underwent comprehensive staging surgery.

Total Parietal Peritonectomy Can Be Performed with Acceptable Morbidity for Patients with Advanced Ovarian Cancer After Neoadjuvant Chemotherapy: Results From a Prospective Multi-centric Study.

Total parietal peritonectomy (TPP) removes areas of "normal-appearing" parietal peritoneum bearing microscopic residual disease and has the potential to improve survival of patients undergoing interval cytoreductive surgery (CRS) for advanced serous epithelial ovarian cancer. This report presents the morbidity outcomes for the first 50 patients enrolled in TORPEDO (CTRI/2018/12/016789), a prospective study. All the patients underwent a TPP during interval CRS. A surgicalprotocol that includes a description ofthe boundaries for each of the five peritonectomies was followed. The common toxicology criteria for adverse events (CTCAE) classification was used to record 90-day morbidity and mortality. The median Peritoneal Cancer Index (PCI) for 50 patients was 15 (range, 5-37). A complete cytoreduction (CC-0 resection) was obtained in 80%, a CC-1 resection in 16%. Abowel resection was performedin 70% of the patients. Grade 3 or 4 complications were seen in 11 patients (22%), and one patient died within 90days after surgery due to intraperitoneal hemorrhage. The most common complications were postoperative fluid collection requiring aspiration (n = 5), intraperitoneal hemorrhage (n = 2), abdominal wound dehiscence (n = 2), pseudo-obstruction (n = 1), urinary sepsis (n = 2), and ileostomy-related complications (n = 2). No bowel fistulas or anastomotic leaks occurred. Microscopic disease in 'normal appearing'peritoneum adjacent to tumor nodules was observed in 46% of the patients, and in regions given a lesion score of 0 in 34%. The parietal peritoneal regions (0-8) had a higher incidence of residual disease (p < 0.001) and occult disease (p < 0.001). During interval CRS, TPP can be performed with acceptable morbidity and mortality. The pathologic findings further support this therapeutic rationale. Survival outcomes should determine the future role of such a procedure in routine clinical practice.

Melatonin suppresses chronic restraint stress-mediated metastasis of epithelial ovarian cancer via NE/AKT/\u03b2-catenin/SLUG axis

Chronic stress has been shown to facilitate progression of epithelial ovarian cancer (EOC), however, the neuro-endocranial mechanism participating in this process still remains unclear. Here, we reported that chronic restraint stress (CRS) promoted the abdominal implantation metastasis of EOC cells and the expression of epithelial–mesenchymal transition-related markers in tumor-bearing mouse model, including TWIST, SLUG, SNAIL, and β-catenin. We observed that β-catenin co-expressed with SLUG and norepinephrine (NE) in tumor tissues obtained from nude mice. Further ex vivo experiments revealed that NE promoted migration and invasion of ovarian cancer cells and SLUG expression through upregulating expression and improving transcriptional function of β-catenin in vitro. A human phosphor-kinase array suggested that NE activated various kinases in ovarian cancer cells, and we further confirmed that AKT inhibitor reduced NE-mediated pro-metastatic impacts and activation of the β-catenin/SLUG axis. Furthermore, the expression levels of NE and β-catenin were examined in ovarian tumor tissues by using tumor tissue arrays. Results showed that the expression levels of both NE and β-catenin were associated with poor clinical stage of serous EOC. Moreover, we found that melatonin (MLT) effectively reduced the abdominal tumor burden of ovarian cancer induced by CRS, which was partially related to the inhibition of the NE/AKT/β-catenin/SLUG axis. Collectively, these findings suggest a novel mechanism for CRS-mediated ovarian cancer metastasis and MLT has a potential therapeutic efficacy against ovarian cancer.

MicroRNA Expression Profiling of Epithelial Ovarian Cancer Identifies New Markers of Tumor Subtype.

Epithelial Ovarian Cancer (EOC) is often challenging to diagnose, even though histological examination. MicroRNA (miRNA or miRNA) is bound to the target messenger RNA (mRNA) due to which the mRNA molecules are silenced. The identification of miRNA expression- based EOC subtypes is considered a critical means of prognostication. So far, the studies on EOC subtypes have not been well characterized. This study aimed to confirm the existence of miRNAs in EOC and to assess their potential as clinical biomarkers for EOC. We sampled 25 ovarian tumor tissues from patients with human ovarian tumors (17 malignant; 12 serous EOC, five non-serous EOC, and eight benign ovarian tumors). miRNA microarray detection was performed to identify EOC miRNAs. Real-time PCR was adapted for the validation of differentially expressed miRNAs detected by microarray analysis related to hybridization intensity. The results confirmed that miRNAs exist in EOC, relative expression of EOC miRNAs demonstrated that the upregulation of miR-483-5p, and downregulation of miR-127-3p, and miR- 532-5p were significantly expressed in the malignant group than in the benign group at p < 0.05. Besides, miR-483-5p could also distinguish EOC subtypes between serous EOC and non-serous EOC, with a p < 0.05. A comprehensive miRNA expression profiling can help to refine subtype classification in EOC, opening new opportunities for identifying clinically applicable markers for improved stratification and diagnostics of ovarian tumors.

The Landscape and Therapeutic Implications of Molecular Profiles in Epithelial Ovarian Cancer.

Epithelial ovarian cancer (EOC) affects 43,000 women worldwide every year and has a five-year survival rate of 30%. Mainstay treatment is extensive surgery and chemotherapy. Outcomes could be improved by molecular profiling. We conducted a review of the literature to identify relevant publications on molecular and genetic alterations in EOC. Approximately 15% of all EOCs are due to BRCA1 or BRCA2 mutations. Four histologic subtypes characterized by different mutations have been described: serous, endometrioid, mucinous, and clear-cell. Between 20–30% of high-grade serous EOCs have a BRCA mutation. Tumors with BRCA mutations are unable to repair double-strand DNA breaks, making them more sensitive to platinum-based chemotherapy and to PolyAdenosine Diphosphate-Ribose Polymerase (PARP) inhibitors. Olaparib is a PARP inhibitor with proven efficacy in BRCA-mutated ovarian cancer, but its effectiveness remains to be demonstrated in tumors with a BRCAness (breast cancer) profile (i.e., also including sporadic tumors in patients with deficient DNA repair genes). A universally accepted molecular definition of BRCAness is required to identify optimal theranostic strategies involving PARP inhibitors. Gene expression analyses have led to the identification of four subgroups of high-grade serous EOC: mesenchymal, proliferative, differentiated, and immunoreactive. These subtypes are not mutually exclusive but are correlated with prognosis. They are not yet used in routine clinical practice. A greater understanding of EOC subtypes could improve patient management.

Modelling Epithelial Ovarian Cancer in Mice: Classical and Emerging Approaches.

High-grade serous epithelial ovarian cancer (HGSC) is the most aggressive subtype of epithelial ovarian cancer. The identification of germline and somatic mutations along with genomic information unveiled by The Cancer Genome Atlas (TCGA) and other studies has laid the foundation for establishing preclinical models with high fidelity to the molecular features of HGSC. Notwithstanding such progress, the field of HGSC research still lacks a model that is both robust and widely accessible. In this review, we discuss the recent advancements and utility of HGSC genetically engineered mouse models (GEMMs) to date. Further analysis and critique on alternative approaches to modelling HGSC considers technological advancements in somatic gene editing and modelling prototypic organs, capable of tumorigenesis, on a chip.

Abstract B04: Immune modeling analysis identifies ICOS and CTLA-4 as predictive biomarkers in serous epithelial ovarian cancer

Abstract Objective: The goal of this study is to comprehensively determine the most clinically relevant immune checkpoint receptor in epithelial ovarian cancer (EOC). Methods: Stage III, Grade III EOC formalin-fixed, paraffin-embedded (FFPE) tumors from ten patients were submitted to Cofactor Genomics to undergo RNA sequencing and machine learning analysis to determine immune cell content and levels of the ten most studied immune escape genes. Patient samples were stratified by high progression-free survival (PFS) of 65 months or greater (n=5) and low PFS of 7 months or less (n=5). All patient tumors submitted were from primary debulking surgery and were naïve to chemotherapy. Immunohistochemistry (IHC) was employed to validate findings. Results: The two immune escape genes ICOS and CTLA-4 were found to be the most predictive biomarkers differentiating short and long PFS. ICOS median transcripts per million (TPM) were 418 and 1,621 in patients with short and long PFS, respectively (p&amp;lt;0.03), while median TPM for CTLA-4 were 1,294 and 4,045 in patients with short and long PFS, respectively (p&amp;lt;0.03). In addition, PD-1 exhibited a median TPM of 817 in patients with short PFS compared to 2455 in patients with long PFS (p&amp;lt;0.05). Immune cell profiling revealed a statistically significant (p&amp;lt;0.05) lower percentage of M2 macrophages in patients with a long PFS (1.07%) compared to patients with a short PFS (2.13%). Higher percentages of CD4+ T cells, CD8+ T cells, CD19+ B cells, and Tregs were detected in patients with a longer PFS compared to short; however, these differences did not reach statistical significance. It was discovered that immune escape genes PD-1, PD-L1, CTLA-4, OX40, TIM3, and ICOS all significantly correlated (p&amp;lt;0.05) to the percentage of CD8+ T cells and total immune cell content. CD47 levels significantly inversely correlated to total immune cell percentages (p&amp;lt;0.02). OX40 was the only immune escape gene that significantly correlated to percentage of CD4+ T cells (p&amp;lt;0.03). PD-1, PD-L1, CTLA-4, OX40, and ICOS all correlated significantly to the percentage of CD19+ B cells (p&amp;lt;0.02). Finally, PD-L1, CTLA-4, OX40, TIM3, and ICOS all significantly correlated to Treg levels (p&amp;lt;0.03). Conclusions: Immune modeling analysis revealed ICOS and CTLA-4 as the most predictive immune biomarkers for PFS in EOC. Interestingly, it was discovered that levels of both activating and inhibitory immune checkpoint receptors correlate to a higher percentage of immune cell populations, indicating overall immune content is important in predicting improved outcomes. Future directions include repeating this assay in a larger patient cohort to validate the predictive threshold determined for ICOS and CTLA-4. Citation Format: Nicole James, Matthew Oliver, Joyce Ou, Jenna Emerson, Katherine Miller, Erin Lips, Ashley Borgstadt, Paul DiSilvestro, Jennifer Ribeiro. Immune modeling analysis identifies ICOS and CTLA-4 as predictive biomarkers in serous epithelial ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B04.

Abstract A55: DCLK1 mediates tumor stemness and platinum resistance in high-grade serous epithelial ovarian cancer

Abstract Background: Ovarian cancer is the fifth leading cause of cancer death in the United States, with an anticipated 13,000 deaths in the United States in 2017. High-grade serous (HGSOC) sub-type is both the most common and the most lethal histopathology. As more than 85% of patients present with metastatic disease, the 5-year overall survival remains dismal at only 30%. It is known that human cancers are initiated and maintained by self-renewing stem cells. Cancer stem cell related protein Doublecortin-like kinase 1 (DCLK1) is a major regulator of stemness and EMT, promoting drug resistance, tumor dormancy, progression, and metastasis in solid tumors. The molecular mechanisms of DCLK1 in tumorigenesis and drug resistance remain limited but DCLK1 expression is increased in cancer, especially in the drug-resistant setting. Results: Our lab has made the discovery that DCLK1 is overexpressed in HGSOC where it regulates tumor progression, tumor stemness, and EMT via noncoding RNA regulation of downstream oncogenic pathways. Our study involved assessment of DCLK1 expression in tissue culture and xenografts created from primary patient-derived cell lines (PDACs). Expression of the DCLK1 protein was assessed by immunoblot analysis in lysates of cell lines representing HGSOC and PDACs obtained from the ascites of patients at the University of Oklahoma at the time of diagnosis, prior to initiation of chemotherapy. FTE-187, FTE-188, and OSE cells were used as normal controls. Elevated levels of DCLK1 expression were observed in the panel of HGSOC cell lines and in PDAC lines. Our in vitro studies confirmed DCLK1 upregulation in the tissue and stroma of PDAC lines and our in vivo studies with PDAC xenografts revealed that siRNA knockdown of DCLK1 negatively regulated tumor suppressor miRNAs including mi-143/145, let-7a, and miR-200a-c resulting in downregulation of pluripotency, EMT, and proangiogenic markers including OCT4, SOX2, KLF4, NANOG, LIN28B, NOTCH, KRAS, and c-MYC. This was most pronounced in the setting of platinum resistance. For this, lysates from paired cells lines with known platinum-sensitive and platinum-resistant variants were assessed (Tyk-nu/Tyk-nu CPR and A2780/A2780.cp). An increase in DCLK1 expression was observed in both of the platinum-resistant lines compared to the platinum-sensitive lines. This was confirmed in PDACs where clinical platinum status correlated with DCLK1 expression, suggesting the role of DCLK1 in inherent platinum-resistant tumor clones. Conclusions: Our data implicate DCLK1 in ovarian cancer pathogenesis and platinum resistance and indicate that DCLK1 knockdown via may suppress malignant progression and resensitize tumors to platinum chemotherapy. These data could have a significant impact on future therapeutic strategies involving DCLK1 inhibitors in treating platinum-resistant patients. Given the high recurrence rate and inevitable development of platinum-resistant disease, such compounds have high potential to impact clinical outcomes in this lethal malignancy. Citation Format: Katherine M. Moxley, JiHee Ha, Daniel Andrade, Courtney Houchen, Danny Dhanasekaran. DCLK1 mediates tumor stemness and platinum resistance in high-grade serous epithelial ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr A55.

Abstract A34: Targeting Protein Phosphatase 2A in Combination with PARP inhibitors for the treatment of high-grade serous epithelial ovarian cancer

Abstract Ovarian cancer (OvC) is the deadliest of all female gynecologic malignancies, ranking as the fifth cause of cancer-related deaths among women. High-grade serous epithelial ovarian cancer (HGSOC) accounts for almost 90% of all forms of OvC, remaining as the most lethal subtype of ovarian malignancies. HGSOC is usually diagnosed at a later stage at which the disease has already progressed into metastatic, having a 5-year survival rate of only 17%. Treatment of HGSOC relies on aggressive approaches including surgery and platinum-based chemotherapies, with the majority of cases requiring combination of both. The molecular mechanism driving ovarian tumorigenesis is not fully understood, and its investigation is essential to provide better and novel therapeutic options for the treatment and cure of this disease. Targeted therapies have been vastly explored in the cancer research field due to their promise in reducing side effects by specifically targeting oncogenic pathways predominantly deregulated in human malignancies. DNA damage and repair (DDR) pathway aberrations and genomic instability are two main hallmarks of OvC. Extensive efforts in targeting this pathway have been devoted to introduce new drugs in the clinic that can target the DDR and homologous recombination (HR) pathways as therapeutic means for treatment of HGSOC. The use of PARP inhibitors (PARPi) to achieve synthetic lethality in OvC has been shown to have great promise in efficiently reducing tumor burden by specifically targeting tumor cells for cell death. However, PARPi’s antitumoral efficacy alone is limited by the status of the BRCA1/2 genes, narrowing down the patient population that can benefit from such therapies. Eventually, patients treated with PARPi alone relapse and develop resistant OvC, for which treatment options available are extremely limited. Our preliminary data show that first-in-class small-molecule activators of PP2A (SMAPs) in combination with PARPi can effectively reduce tumor burden in PDX models, promoting a synergistic effect in platinum-sensitive and -resistant OvC tumors, despite the BRCA gene status. Protein Phosphatase 2A (PP2A) and Protein Phosphatase 1 (PP1) account for 90% of all serine/threonine phosphatase activity in the cell and act as two main tumor suppressors. These phosphatases tightly regulate signaling pathways involved with cell cycle, growth, migration, metabolism, survival and many oncogenic pathways by counteracting kinases. HGSOC tumors express inactivated PP2A due to PPP2RA1 heterozygous loss, although lacking mutations, making it an ideal target for reactivation in these cancers. Moreover, we have shown that reactivation of PP2A via SMAPs leads to potent inhibition of several key DDR proteins. We have found that SMAPs treatment in BRCA1/2 WT tumors confers a “BRCAness” phenotype, which sensitizes tumors to DNA repair inhibitors such as PARPi. In sum, SMAPs can allow us to expand the patient population that can benefit from PARPi therapies and possibly overcome drug resistance. Citation Format: Rita A. Avelar, Amy Armstrong, Goutham Narla, Analisa DiFeo. Targeting Protein Phosphatase 2A in Combination with PARP inhibitors for the treatment of high-grade serous epithelial ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr A34.

Detection of TP53 Clonal Variants in Papanicolaou Test Samples Collected up to 6 Years Prior to High-Grade Serous Epithelial Ovarian Cancer Diagnosis

The low 5-year survival rate of women with high-grade serous epithelial ovarian cancer (HGS-EOC) is related to its late diagnosis; thus, improvement in diagnosis constitutes a crucial step to increase the curability of this disease. To determine whether the presence of the clonal pathogenic TP53 variant detected in matched primary tumor biopsies can be identified in DNA purified from Papanicolaou test samples collected from women with HGS-EOC years before the diagnosis. This cohort study was conducted among a single-center cohort of women with histologically confirmed diagnosis of HGS-EOC recruited at San Gerardo Hospital, Monza, Italy, from October 15, 2015, to January 4, 2019. Serial dilutions of DNA derived from tumor samples and DNA extracted from healthy women's Papanicolaou test samples were analyzed to define the sensitivity and specificity of droplet digital polymerase chain reaction assays designed to detect the TP53 variants identified in tumors. All available brush-based Papanicolaou test slides performed up to 6 years before diagnosis were investigated at the Mario Negri Institute, Milano, Italy. Data were analyzed from October 2018 to December 2019. The presence of tumor pathogenic TP53 variants was assessed by the droplet digital polymerase chain reaction approach in DNA purified from Papanicolaou test samples obtained from the same patients before diagnosis during cervical cancer screenings. Among 17 included patients (median [interquartile range] age at diagnosis, 60 [53-69] years), Papanicolaou tests withdrawn before diagnosis presented tumor-matched TP53 variants in 11 patients (64%). In 2 patients for whom longitudinal Papanicolaou tests were available, including 1 patient with Papanicolaou tests from 25 and 49 months before diagnosis and 1 patient with Papanicolaou tests from 27 and 68 months before diagnosis, the TP53 clonal variant was detected at all time points. These findings suggest that noninvasive early molecular diagnosis of HGS-EOC is potentially achievable through detection of TP53 clonal variants in the DNA purified from Papanicolaou tests performed during cervical cancer screening.

Abstract C070: Racial disparities in body mass index and ovarian cancer risk in the OCWAA Consortium

Abstract Objective: Obesity disproportionately affects African American (AA) women, and there is some suggestion that its association with ovarian cancer risk may be stronger among AA compared to white women, but no study to date has been adequately powered to compare risk between the two populations. The Ovarian Cancer in Women of African Ancestry (OCWAA) Consortium provided a unique opportunity to evaluate the association between body mass index (BMI) and invasive epithelial ovarian cancer (EOC) risk in AA and white women and to estimate the contribution of obesity to ovarian cancer risk in both racial groups. Methods: The OCWAA Consortium is a collaboration of six of the largest epidemiologic studies of ovarian cancer in the United States that include AA women: four case-control and two case-control studies nested within cohort studies. The six studies are the Chicago Case-Control Study, the North Carolina Ovarian Cancer Study, the Los Angeles Ovarian Cancer Case-Control Studies, the African American Cancer Epidemiology Study, the Black Women’s Health Study, and the Multiethnic Cohort. BMI before diagnosis was available in all the studies and data on BMI and relevant confounders were harmonized for analyses. There were 1,144 AA cases, 2,910 AA controls, 3,174 white cases, and 9,160 white controls included. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were computed using random-effects multi-level logistic regression models separately by race and histotype with control for relevant covariates, which included study, age, education, parity, oral contraceptive use, age at menarche and family history of breast/ovarian cancer. Multinomial regression was used for histotype analyses. Population attributable risk (PAR) estimates were computed by race and histotype. Results: The prevalence of obesity (BMI≥30 kg/m2) was higher in AAs compared to white women for both cases (53.2% vs 21.4%) and controls (45.7% vs. 18.4%). For EOC, there was little evidence of an association with obesity for white women. For AAs, risk was elevated for BMI≥30 kg/m2 (ORBMI 30-34=1.37, 95% CI: 1.12, 1.69; ORBMI≥35 = 1.26, 95% CI: 0.74, 2.15) relative to BMI 18.5-&amp;lt;25 kg/m2. There was an elevated risk for non-high-grade serous EOC for both AA and white women (for AA women, ORBMI 30-34=1.67, 95% CI: 1.14, 2.44 and ORBMI≥35 = 1.76; 95% CI: 0.84, 3.69; for white women, ORBMI ≥35 = 1.39; 95% CI: 1.06, 1.82), but not for high-grade serous EOC. The PAR for BMI≥30 was 7.1% (95% CI: 2.4, 15.6) for AAs and 2.6% (95% CI: -0.3, 5.4) for whites for all EOC. For non-high-grade serous EOC, the PAR was 16.5% (95% CI: 3.4, 28.2) for AAs and 6.4% (95% CI: 2.2, 10.3) for whites. Conclusions: Obesity was a contributor to overall EOC risk among AA women but not among white women. Obesity did not contribute to the risk of high-grade serous EOC for AAs or whites, but it was associated with non-high-grade serous cases among both AA and white women. The association with non-high-grade serous EOC was greater among AAs than whites. Citation Format: Elisa V Bandera, Fabian Camacho, Deanna Chyn, Emily K Cloyd, Traci N Bethea, Alicia Beeghly-Fadiel, Charlotte E Joslin, Evan Myers, Patricia G Moorman, Heather M Ochs-Balcom, Holly R Harris, Lauren C Peres, Veronica Wendy Setiawan, Anna H Wu, Lynn Rosenberg, Joellen M Schildkraut. Racial disparities in body mass index and ovarian cancer risk in the OCWAA Consortium [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C070.

OvarianTag biomarker panel in order guide treatment decisions cisplatin-based for women with epithelial ovarian cancer.

e18075 Background: Ovarian cancer (OC) represents the most lethal gynecologic cancer. Late-stage diagnosis associated with a lack of effective markers to detect chemotherapy resistance contributes to high mortality and poor prognosis of epithelial ovarian cancer (EOC). OvarianTag Biomarkers Panel was developed as biopsy-based gene expression assay to discriminate prognosis in EOC patients, to understand the aggressiveness and relapse causes of these patients. Methods: Patients were admitted into this study in two phases. First, 45 women were included prospectively, and RNA was obtained from fresh normal ovarian (NO) tissues (n = 18), ovarian serous cystadenoma tumors (n = 11) and EOC (n = 16). The total RNA content was quantified and quantitative PCR (qRT-PCR) was performed to determine relative gene expression, starting set genes related to apoptosis and necroptosis regulated cell death pathway. Machine Learning algorithms were used to classify patient’s data associated and to characterize molecular targets as prognostic markers, named OvarianTag panel. Later, others 55 EOC patients, attended between 2008 and 2016, were included. Within this cohort, tissues were obtained from 106 FFPE samples and shared into primary and metastatic EOC, and from the same NO tissues (as control). RNA was extracted and qRT-PCR determined the OvarianTag panel expression level from each sample. Then, hierarchical clustering allowed us to classify the samples using the cut off obtained by classifier algorithm. Results: Significant differences in gene expression profile were observed between patients’ groups. Molecular classifier algorithm proved the prognostic value of genes evaluated. Decisions trees and biomarker clusters were constructed. In the full training, were obtained 90% of correct classifications and in cross-validation, 89%. In the second phase, the classifier reported specificity of 100% and sensibility of 79% to predict tumor recurrence and platinum resistance. Conclusions: OvarianTag panel is a putative prognosis biomarker of EOC subgroups and could be considered to drive the clinical practice of EOC treatment options, improving outcomes because providing an opportunity for guide clinical intervention for increasing survival rates. Besides of that, it will be allowed include patients in clinical trials of new target drugs or for repositioning of target drugs that have already been tested in humans.

A clinical study of tremelimumab alone or in combination with olaparib in patients with advanced epithelial ovarian cancer.

6045 Background: Single agent immunotherapy (IO) has shown only modest clinical activity for the treatment of ovarian cancer. The combination of anti-programmed death-1 and PARP inhibitors showed promising activity in early trials. Here, we report the results of an open-label, parallel arm, dose escalation study of tremelimumab (T) alone or in combination with olaparib (O) in patients (pts) with advanced epithelial ovarian cancer (EOC). Methods: Pts with recurrent/persistent EOC who had progression &lt; 12 months from last platinum exposure were enrolled. Prior therapy with IO (except anti-CTLA-4) or PARP inhibitor was allowed. Pts were randomized to either T 10mg/kg every 4 weeks (wks) x 7 then every 12 wks (Arm A) or T with O twice daily at three planned dose levels (Arm B). The primary objectives were safety, pharmacodynamic (PD) change in CD4+ICOShi peripheral T cells by flow cytometry, and identification of the optimal dose combination of T with O. Secondary objectives included 6-month progression-free survival (PFS6) and objective response rate (ORR). Results: A total of 24 pts were treated, 12 on Arm A, and 12 on two Arm B dose levels. Pts had a median age of 60 years (range 44-81). Histologic subtypes included high-grade serous EOC (20 pts, 83%), clear cell (3 pts, 13%), and moderately-differentiated adenocarcinoma (1 pt, 4%). BRCA1 mutation (mt) was present in 2 cases, BRCA2 mt in 1. Median number of prior regimens was 3.5 (range 1-9). Most adverse events (AEs) were attributable to T, the most common grade 3 toxicities were rash (13%), immune-mediated hepatitis (8%), and colitis (8%). No grade ≥4 toxicities were identified. Immune-mediated AEs also included acute kidney injury, hypophysitis, and hypothyroidism. No dose limiting toxicities were identified on Arm B. Two pts in Arm B had &gt;PFS6. Of 20 pts evaluable for response, there was 1 partial response (Arm B), and 9 pts had stable disease (6 on Arm A, 3 on Arm B). Mean percentage of CD4+ICOShi T cells was significantly increased on Days 15 and 22 compared to Day 1 at both T dose levels (Table).T at 3 mg/kg with O at 150mg is the optimal dose of those tested. Conclusions: T and T with O was tolerable, with modest clinical activity in this pt population. AEs were as expected, and peripheral CD4+ICOShi T cells increased on therapy. Clinical trial information: 02485990. [Table: see text]

ABCC4/MRP4 contributes to the aggressiveness of Myc-associated epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) is a complex disease comprising discrete histological and molecular subtypes, for which survival rates remain unacceptably low. Tailored approaches for this deadly heterogeneous disease are urgently needed. Efflux pumps belonging to the ATP-binding cassette (ABC) family of transporters are known for roles in both drug resistance and cancer biology and are also highly targetable. Here we have investigated the association of ABCC4/MRP4 expression to clinical outcome and its biological function in endometrioid and serous tumors, common histological subtypes of EOC. We found high expression of ABCC4/MRP4, previously shown to be directly regulated by c-Myc/N-Myc, was associated with poor prognosis in endometrioid EOC (P = .001) as well as in a subset of serous EOC with a "high-MYCN" profile (C5/proliferative; P = .019). Transient siRNA-mediated suppression of MRP4 in EOC cells led to reduced growth, migration and invasion, with the effects being most pronounced in endometrioid and C5-like serous cells compared to non-C5 serous EOC cells. Sustained knockdown of MRP4 also sensitized endometrioid cells to MRP4 substrate drugs. Furthermore, suppression of MRP4 decreased the growth of patient-derived EOC cells in vivo. Together, our findings provide the first evidence that MRP4 plays an important role in the biology of Myc-associated ovarian tumors and highlight this transporter as a potential therapeutic target for EOC.

Serologic markers of Chlamydia trachomatis and other sexually transmitted infections and subsequent ovarian cancer risk: Results from the EPIC cohort.

A substantial proportion of epithelial ovarian cancer (EOC) arises in the fallopian tube and other epithelia of the upper genital tract; these epithelia may incur damage and neoplastic transformation after sexually transmitted infections (STI) and pelvic inflammatory disease. We investigated the hypothesis that past STI infection, particularly Chlamydia trachomatis, is associated with higher EOC risk in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort including 791 cases and 1669 matched controls. Serum antibodies against C. trachomatis, Mycoplasma genitalium, herpes simplex virus type 2 (HSV-2) and human papillomavirus (HPV) 16, 18 and 45 were assessed using multiplex fluorescent bead-based serology. Conditional logistic regression was used to estimate relative risks (RR) and 95% confidence intervals (CI) comparing women with positive vs. negative serology. A total of 40% of the study population was seropositive to at least one STI. Positive serology to C. trachomatis Pgp3 antibodies was not associated with EOC risk overall, but with higher risk of the mucinous histotype (RR = 2.30 [95% CI = 1.22-4.32]). Positive serology for chlamydia heat shock protein 60 (cHSP60-1) was associated with higher risk of EOC overall (1.36 [1.13-1.64]) and with the serous subtype (1.44 [1.12-1.85]). None of the other evaluated STIs were associated with EOC risk overall; however, HSV-2 was associated with higher risk of endometrioid EOC (2.35 [1.24-4.43]). The findings of our study suggest a potential role of C. trachomatis in the carcinogenesis of serous and mucinous EOC, while HSV-2 might promote the development of endometrioid disease.

Imiquimod Inhibits Proliferation of Serous Epithelial Ovarian Cancer Cells In Vitro: A Preliminary Study

Imiquimod, known as positive immune response modifier and stimulates local cytokine induction, has been used in therapy of genital warts via increasing local interferon and reducing human papillomavirus production. We aimed to investigate whether imiquimod has any effect on the proliferation of serous epithelial ovarian cancer cells in vitro. The study was designed in two stages. The first stage was designed to evaluate co-culturing of serous epithelial ovarian cancer cells with the drug imiquimod versus cancer cells cultured with no drug. The second stage of the study was initiated with primary ovarian cancer cell culture growth. Imiquimod was applied in increasing concentrations to flasks full of each kind of cells. Also, histomorphometrical evaluation was made using an unbiased counting frame. Treatment of the primary cancer cell cultures with imiquimod in concentrations of 2.5 μg/ml and 5.0 μg/ml did not result in a significant effect on cell proliferation and the cell proliferation continued. Cell proliferation stopped and the cells detached at concentrations of 7.5 μg/ml, especially 10.0 μg/ml, 12.5 μg/ml, and 25.0 μg/ml, within 2–3 days after exposure to the drug. The anti-proliferative effect of imiquimod reached a maximum level at a concentration of 12.5 μg/ml. Imiquimod has a dose-dependent anti-proliferative impact on serous epithelial ovarian cancer cells in vitro.

Predictive and Prognostic Relevance of p53 in Patients With Serous Epithelial Ovarian Cancer

Background: Ovarian cancer is a common malignant gynecological tumor that is difficult to diagnose early, progresses rapidly, and causes high mortality. Aims of our study: to assess the relationship of P53 with other clinico-pathological parameters and the effect of P53 on patients’ out-come. Subjects and methods: This study was conducted at Clinical Oncology and Nuclear Medicine Department with Pathology Department, Faculty of Medicine, Mansoura University. The study was carried out on 50 patients with serous epithelial ovarian cancer presented to receive adjuvant treatments following a primary surgery and were followed from the first day after surgery, follow-up started on January, 2012 till February, 2016. P53 expression was assessed immunohistochemically on formalin-fixed paraffin-embedded tissues, and Secondary red Envision system. Patients were given adjuvant treatment(s) according to according to NCCN guidelines. The primary endpoint of the study was loco regional recurrence, and distant metastasis. At the end of the follow-up period, the patient clinico-pathological data and patient outcome were collected. Results: we found that p53 negative tumors have a better OS & DFS at 3 year than with P53 positive tumors, but not reached statistically significant differences ( p value = 0.98 & 0.48 respectively). Conclusion: Our results showed no statically significant difference between p53 expression. OS & DFS, need to be evaluated in other study including large number of patients before using it as a marker for the outcome in these tumors.

Decoding molecular interplay between RUNX1 and FOXO3a underlying the pulsatile IGF1R expression during acquirement of chemoresistance

Hyperactive Insulin like growth factor-1-receptor (IGF1R) signalling is associated with development of therapy resistance in many cancers. We recently reported a pulsatile nature of IGF1R during acquirement of platinum-taxol resistance in Epithelial Ovarian Cancer (EOC) cells and a therapy induced upregulation in IGF1R expression in tumors of a small cohort of high grade serous EOC patients. Here, we report Runt-related transcription factor 1 (RUNX1) as a novel transcriptional regulator which along with another known regulator Forkhead Box O3 (FOXO3a), drives the dynamic modulation of IGF1R expression during platinum-taxol resistance development in EOC cells. RUNX1-FOXO3a cooperatively bind to IGF1R promoter and produce a transcriptional surge during onset of resistance and such co-operativity falls apart when cells attain maximal resistance resulting in decreased IGF1R expression. The intriguing descending trend in IGF1R and FOXO3a expressions is caused by a Protein Kinase B (AKT)-FOXO3a negative feedback loop exclusively present in the highly resistant cells eliciting the pulsatile behaviour of IGF1R and FOXO3a. In vivo molecular imaging revealed that RUNX1 inhibition causes significant attenuation of the IGF1R promoter activity, decreased tumorigenicity and enhanced drug sensitivity of tumors of early resistant cells. Altogether our findings delineate a dynamic interplay between several molecular regulators driving pulsatile IGF1R expression and identify a new avenue for targeting EOC through RUNX1-IGF1R axis during acquirement of chemoresistance.

PIK3R1W624R Is an Actionable Mutation in High Grade Serous Ovarian Carcinoma.

Identifying cancer drivers and actionable mutations is critical for precision oncology. In epithelial ovarian cancer (EOC) the majority of mutations lack biological or clinical validation. We fully characterized 43 lines of Patient-Derived Xenografts (PDXs) and performed copy number analysis and whole exome sequencing of 12 lines derived from naïve, high grade EOCs. Pyrosequencing allowed quantifying mutations in the source tumours. Drug response was assayed on PDX Derived Tumour Cells (PDTCs) and in vivo on PDXs. We identified a PIK3R1W624R variant in PDXs from a high grade serous EOC. Allele frequencies of PIK3R1W624R in all the passaged PDXs and in samples of the source tumour suggested that it was truncal and thus possibly a driver mutation. After inconclusive results in silico analyses, PDTCs and PDXs allowed the showing actionability of PIK3R1W624R and addiction of PIK3R1W624R carrying cells to inhibitors of the PI3K/AKT/mTOR pathway. It is noteworthy that PIK3R1 encodes the p85α regulatory subunit of PI3K, that is very rarely mutated in EOC. The PIK3R1W624R mutation is located in the cSH2 domain of the p85α that has never been involved in oncogenesis. These data show that patient-derived models are irreplaceable in their role of unveiling unpredicted driver and actionable variants in advanced ovarian cancer.