High-grade Serous Cancer Research Articles

Abstract 794: Trends of ovarian cancer incidence by histotype and race/ethnicity in the U.S.: 1992-2017

Abstract Background: Ovarian cancer incidence rates in the U.S. decreased since the early 1970s, which was largely attributed to increasing parity among birth cohorts through 1935 and the introduction of combined oral contraceptives (COCs) in the 1960s. However, COC use prevalence has dramatically declined among 20-34 year-olds since the early 2000s as has parity. Ovarian cancer histotypes share many risk factors, including parity and COC use, but the magnitude of the effects differs by histotype. In addition, the prevalence of these risk factors differs by race/ethnicity. Understanding the trends in ovarian cancer incidence by histotype and race/ethnicity will allow us to consider the impact of changes in risk factor profiles. Methods: Ovarian cancer incidence rates in 1992-2017 were obtained from the Surveillance, Epidemiology, and End Results (SEER) 13 registry. Age-standardized ovarian cancer incidence trends for the three most common histotypes (high-grade serous (HGS), endometrioid and clear cell) and four racial/ethnic groups (Hispanic, Asian/Pacific Islander (API), non-Hispanic Black (NHB), and non-Hispanic White (NHW)) were analyzed using joinpoint regression. Temporal trends of each histotype were analyzed using age-period-cohort models. Results: Joinpoint regression analysis: NHW had the highest incidence rates for HGS and endometrioid cancers, while API had the highest rate for clear cell cancer. HGS cancer incidence declined in all racial/ethnic groups during 1992-2017; NHW had the greatest reduction. Endometrioid cancer incidence decreased in NHW and NHB but increased in Hispanics in recent years. All racial/ethnic groups showed an increasing trend of clear cell cancer incidence. Age-period-cohort analysis: HGS cancer incidence has been decreasing in NHW and API by birth cohort, but not in NHB or Hispanics. There is a decreasing trend in HGS cancer incidence by period in NHW, but no clear period-specific pattern was observed among other racial/ethnic groups. Endometrioid cancer incidence has been decreasing in NHW and API, but increasing in NHB and Hispanics in recent cohorts. Clear cell cancer incidence has been increasing by birth cohort in all racial/ethnic groups. Conclusions: HGS and endometrioid cancer incidence has been decreasing overall, but clear cell cancer incidence has been increasing. This may be due to an improvement in diagnosis with a shift from classifying “carcinoma, not otherwise specified” to clear cell cancer. It is also possible that the impact of shifting patterns of lower COC use and parity are having a bigger impact on clear cell cancer given that these exposures are more protective for this histotype. Further, the introduction of opportunistic salpingectomy may balance any impact of COC use or parity changes for HGS cancer. There are differences in the ovarian cancer incidence trends by histotype and race/ethnicity, highlighting the impact of different preventive strategies. Citation Format: Minh Tung Phung, Celeste Leigh Pearce, Rafael Meza, Jihyoun Jeon. Trends of ovarian cancer incidence by histotype and race/ethnicity in the U.S.: 1992-2017 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 794.

A novel decision tree model based on chromosome imbalances in cell-free DNA and CA-125 in the differential diagnosis of ovarian cancer.

CA-125 is widely used as biomarker of ovarian cancer. However, CA-125 suffers low accuracy. We developed a hybrid analytical model, the Ovarian Cancer Decision Tree (OCDT), employing a two-layer decision tree, which considers genetic alteration information from cell-free DNA along with CA-125 value to distinguish malignant tumors from benign tumors. We consider major copy number alterations at whole chromosome and chromosome-arm level as the main feature of our detection model. Fifty-eight patients diagnosed with malignant tumors, 66 with borderline tumors, and 10 with benign tumors were enrolled. Genetic analysis revealed significant arm-level imbalances in most malignant tumors, especially in high-grade serous cancers in which 12 chromosome arms with significant aneuploidy (P<0.01) were identified, including 7 arms with significant gains and 5 with significant losses. The area under receiver operating characteristic curve (AUC) was 0.8985 for copy number variations analysis, compared to 0.8751 of CA125. The OCDT was generated with a cancerous score (CScore) threshold of 5.18 for the first level, and a CA-125 value of 103.1 for the second level. Our most optimized OCDT model achieved an AUC of 0.975. The results suggested that genetic variations extracted from cfDNA can be combined with CA-125, and together improved the differential diagnosis of malignant from benign ovarian tumors. The model would aid in the pre-operative assessment of women with adnexal masses. Future clinical trials need to be conducted to further evaluate the value of CScore in clinical settings and search for the optimal threshold for malignancy detection.

Modification of intrinsic ovarian cancer tumor factors by Wnt-pathway agents influences macrophage recruitment and activity.

e14514 Background: The Wnt/B-catenin pathway is associated with a “cold” phenotype in the gynecologic malignancy tumor microenvironment (TME), resulting in immunosuppression. Research is limited regarding this pathway’s effects on TME myeloid cell populations. We aimed to characterize the impact of Wnt pathway modulation on macrophage activity in ovarian cancer. Methods: Syngeneic murine models harboring ID8 parental (ID8par) tumors were treated with DKN-01 and CGX-1321 as single agents or in sequence (DKN-01 followed by CGX-1321.) Flow cytometry analyses were performed on harvested omenta and blood. Ascites from 10 high grade serous epithelial ovarian cancer patients were treated with DKN-01 (Wnt activator) or CGX-1321 (Wnt inhibitor) for 48 hours; multiplex cytokine array was performed to determine changes in cytokine/chemokine expression. Lastly, we performed co-culture analyses on the effects of ID8par and ID8p53-/- isolated cell media on murine macrophage (RAW264.7) activity. Results: In the ID8par model, sequential DKN-01/CGX-1321 resulted in the greatest macrophage influx into the TME. CGX-1321 monotherapy increased the M2:M1 macrophage ratio (pro-tumor) while DKN-01 monotherapy resulted in decreased M2:M1 ratio (anti-tumor.) In human ascites, DKN-01 increased macrophage colony stimulating factor (M-CSF) expression. Of note, ascites from a patient harboring a p53 mutation demonstrated an increase in M1 polarization cytokines IFNy and TNFa in response to DKN-01; CGX-1321 treatment resulted in increased M2 polarization cytokines IL-4 and IL-13. In co-culture analysis, ID8par isolated media increased RAW264.7 migration and polarization towards an M2 phenotype; ID8p53-/- isolated media polarized towards an M1 phenotype. Conclusions: Macrophage activity influences immune responses and tumor behavior. For example, M2 macrophages are pro-tumor and can enhance tumor growth and immune evasion. In our studies, we demonstrated that macrophage recruitment and polarization (M1 vs M2) are influenced by genetic alterations that can be modified by treatment. The ID8par model positively influenced M2 macrophage activity; ID8p53-/- cells positively influenced M1 macrophage activity. Importantly, DKN-01 treatment reverses the M2-dominant phenotype in ID8par model towards M1. These results suggest that p53 mutation and/or DKN-01 treatment in ovarian cancer influences M1 anti-tumor macrophage activity, and posits a novel targetable pathway. Further studies should investigate Wnt/B-catenin modulation on macrophage activity for immunotherapy in gynecologic malignancies.

An international, multicenter, real-world analysis of epithelial ovarian cancer treatment and outcomes.

5531 Background: Few major studies have examined and compared the management and outcomes of patients from diagnosis to death between countries. We have established an international collaboration across Europe and South Korea to compare treatment and outcomes in Epithelial Ovarian Cancer (EOC). Methods: Patients diagnosed with EOC between January 2012 and December 2018 (age ≥18), were included for analysis. Data from medical records from five European and a single South Korean treatment centre were extracted, standardised to a common data model and analysed at each centre using a common script developed in R. Time to each progression/recurrence event (defined as time to next treatment) and overall survival have been estimated using Kaplan Meier methodology and outcomes stratified by categories of interest. Changes in the use of anti-cancer therapies over time and the incidence of BRCA mutations and incidence/timing of second breast cancers have also been examined. Results: A total cohort of 2925 patients was identified with a median age at each centre of 53 to 67 years. Advanced disease (FIGO stage III - IV) (range 57% to 84%) and high-grade serous morphology (38% to 70%) were most common at each centre. The timing of surgery (primary, interval debulking or delayed) and the proportion of patients undergoing surgery varied with stage. Patients with stage I disease where most likely to undergo surgery (range 73% to 100%) and stage IV the least (range 39% to 84%). Median overall survival for high grade serous cancers ranged from 1.9 to 4.9 years, and for the whole cohort from 2.1 to 5.5 years. Median time to next treatment at first relapse for the whole cohort ranged from 14 to 22 months. Second breast cancers were noted in 6 to 17% of patients and the majority of these occurred before the diagnosis of EOC at a median time of 96 to 118 months prior to diagnosis of EOC. Additional data on treatment pathways, BRCA status and outcomes by line of therapy for each centre will be presented. Conclusions: Preliminary analysis of results across this network suggests a variation in patient populations between sites and substantial differences in both treatments and outcomes. The establishment of a common data model and the use of a common analytic script between sites across six different countries allows for detailed exploration of the factors influencing differences in patient management and treatment outcomes in ovarian cancer patients.

Ultrasound characteristics of early-stage high-grade serous ovarian cancer

Survival from ovarian cancer is strongly dependent on the stage at diagnosis. Therefore, when confronted with a woman with an isolated adnexal mass, clinicians worry about missing the opportunity to detect cancer at an early stage. High-grade serous ovarian cancers account for 80% of ovarian cancer deaths, largely because of their tendency to be diagnosed at a late stage. Among adnexal masses, large size and the presence of solid areas on ultrasound examination have been found to be associated with cancer, but it is unclear whether these characteristics identify early-stage cases. This study aimed to evaluate the ultrasound findings associated with clinically detected early-stage high-grade serous ovarian cancer. This was a retrospective cohort study of women diagnosed with stage I or II high-grade serous ovarian or fallopian tube cancer measuring at least 1 cm at pathology from 2007 to 2017. Preoperative ultrasound examinations were independently reviewed by 3 radiologists. Adnexal masses were scored for size and volume; overall appearance; presence, thickness, and vascularity of septations; morphology and vascularity of other solid components; and degree of ascites. Characteristics were compared between masses of <5 cm and larger masses and between stage I and stage II cases. Interobserver variability was assessed. Among 111 women identified, 4 had bilateral ovarian involvement, for a total of 115 adnexal masses characterized by ultrasound examination. The mean age at diagnosis was 61.8 years (range, 42-91 years). The median mass size was 9.6 cm (range, 2.2-23.6 cm) with 87% of cases having a mass size of ≥5 cm. A mixed cystic and solid appearance was most common (77.4%), but a completely solid appearance was more frequently seen for tumors of <5 cm compared with larger tumors (26.7% vs 13.0%). Solid components other than septations were seen in 97.4% of cases. The characteristics of stage I and II cases were similar other than ascites, which was more commonly seen in stage II cases (18.0% vs 3.1%, respectively). Interobserver concordance was high for size and volume measurements (correlation coefficients, 0.96-0.99), with moderate agreement observed across the other ultrasound characteristics (Fleiss kappa, 0.45-0.58). In this community-based cohort, early-stage high-grade serous cancers rarely presented as masses of <5 cm or masses without solid components other than septations. Our findings provide additional support for the observation of small masses without solid areas on ultrasound examination.

Tamoxifen and aromatase inhibitors for relapse of tubo-ovarian high-grade serous cancer

Tamoxifen and aromatase inhibitors for relapse of tubo-ovarian high-grade serous cancer

Fallopian Tube-Derived Tumor Cells Induce Testosterone Secretion from the Ovary, Increasing Epithelial Proliferation and Invasion.

Simple SummaryThe area between the fallopian tube and the ovary is of interest since the ends of the fimbria are the progenitor site for high grade serous cancer. Metabolomics revealed that androgens are induced at this site, which then increased proliferation of normal fallopian tube cells and their migration.The fallopian tube epithelium is the site of origin for a majority of high grade serous ovarian carcinomas (HGSOC). The chemical communication between the fallopian tube and the ovary in the development of HGSOC from the fallopian tube is of interest since the fimbriated ends in proximity of the ovary harbor serous tubal intraepithelial carcinoma (STICs). Epidemiological data indicates that androgens play a role in ovarian carcinogenesis; however, the oncogenic impact of androgen exposure on the fallopian tube, or tubal neoplastic precursor lesions, has yet to be explored. In this report, imaging mass spectrometry identified that testosterone is produced by the ovary when exposed to tumorigenic fallopian tube derived PTEN deficient cells. Androgen exposure increased cellular viability, proliferation, and invasion of murine cell models of healthy fallopian tube epithelium and PAX2 deficient models of the preneoplastic secretory cell outgrowths (SCOUTs). Proliferation and invasion induced by androgen was reversed by co-treatment with androgen receptor (AR) antagonist, bicalutamide. Furthermore, ablation of phosphorylated ERK reversed proliferation, but not invasion. Investigation of two hyperandrogenic rodent models of polycystic ovarian syndrome revealed that peripheral administration of androgens does not induce fallopian proliferation in vivo. These data suggest that tumorigenic lesions in the fallopian tube may induce an androgenic microenvironment proximal to the ovary, which may in turn promote proliferation of the fallopian tube epithelium and preneoplastic lesions.

Chloroxine overrides DNA damage tolerance to restore platinum sensitivity in high-grade serous ovarian cancer

High-grade serous cancer (HGSC) accounts for ~67% of all ovarian cancer deaths. Although initially sensitive to platinum chemotherapy, resistance is inevitable and there is an unmet clinical need for novel therapies that can circumvent this event. We performed a drug screen with 1177 FDA-approved drugs and identified the hydroxyquinoline drug, chloroxine. In extensive validation experiments, chloroxine restored sensitivity to both cisplatin and carboplatin, demonstrating broad synergy in our range of experimental models of platinum-resistant HGSC. Synergy was independent of chloroxine’s predicted ionophore activity and did not relate to platinum uptake as measured by atomic absorption spectroscopy. Further mechanistic investigation revealed that chloroxine overrides DNA damage tolerance in platinum-resistant HGSC. Co-treatment with carboplatin and chloroxine (but not either drug alone) caused an increase in γH2AX expression, followed by a reduction in platinum-induced RAD51 foci. Moreover, this unrepaired DNA damage was associated with p53 stabilisation, cell cycle re-entry and triggering of caspase 3/7-mediated cell death. Finally, in our platinum-resistant, intraperitoneal in vivo model, treatment with carboplatin alone resulted in a transient tumour response followed by tumour regrowth. In contrast, treatment with chloroxine and carboplatin combined, was able to maintain tumour volume at baseline for over 4 months. In conclusion, our novel results show that chloroxine facilitates platinum-induced DNA damage to restore platinum sensitivity in HGSC. Since chloroxine is already licensed, this exciting combination therapy could now be rapidly translated for patient benefit.

Utilizing an interim futility analysis of the OVAL study (VB-111-701/GOG 3018) for potential reduction of risk: A phase III, double blind, randomized controlled trial of ofranergene obadenovec (VB-111) and weekly paclitaxel in patients with platinum resistant ovarian cancer

ObjectiveReport the results from a preplanned interim analysis of a phase III, double blind, randomized controlled study of ofranergene obadenovec (VB-111), a targeted anti-cancer gene therapy, in combination with paclitaxel in patients with platinum resistant ovarian cancer (PROC). MethodsThe OVAL (NCT03398655) study is an on-going study where patients are randomly assigned in a 1:1 ratio to weekly paclitaxel 80 mg/m2 with VB-111 or placebo. The protocol specifies a pre-planned unblinded futility interim analysis of CA-125 response per GCIG criteria in the first 60 evaluable patients. The futility rule determined for this analysis was that the response rate of VB-111 must be greater than the response rate of placebo by at least 10% in order to continue the study. Coincident with the interim analysis, the blinded CA-125 response rate was estimated as a proportion of the first 60 evaluable patients with CA-125 response per GCIG criteria. Post-treatment fever is provided as a possible surrogate marker of VB-111 therapy activity. ResultsThe median age of the evaluable patients was 62 years (range 41–82); 97% had high-grade serous cancer; 58% had been treated with 3 or more previous lines of therapy, 70% received prior anti-angiogenic treatment, 43% received prior PARP inhibitors. CA-125 response in the VB-111 and weekly paclitaxel treated arm met the pre-specified interim criterion of an absolute advantage of 10% or higher compared to the control. Blinded results show a 53% CA-125 response rate (32/60) with 15% complete response (n=9). Assuming balanced randomization and an absolute advantage of 10% or higher to the VB-111 arm, it may be deducted that the response in the VB-111 treatment arm is 58% or higher. Among patients with post-treatment fever, the CA-125 response rate was 69%. ConclusionsAt the time of the interim analysis, response rate findings are comparable to the responses seen in a similar patient population in the phase I/II study. The independent data and safety monitoring committee (iDSMC) recommended continuing the OVAL trial as planned. No new safety signals were identified.

Clinicopathologic and Genomic Analysis of TP53-Mutated Endometrial Carcinomas.

Copy number-high endometrial carcinomas were described by The Cancer Genome Atlas as high-grade endometrioid and serous cancers showing frequent copy-number alterations (CNA), low mutational burden (i.e., non-hypermutant), near-universal TP53 mutation, and unfavorable clinical outcomes. We sought to investigate and compare the clinicopathologic and molecular characteristics of non-hypermutant TP53-altered endometrial carcinomas of four histologic types. TP53-mutated endometrial carcinomas, defined as TP53-mutant tumors lacking microsatellite instability or pathogenic POLE mutations, were identified (n = 238) in a cohort of 1,239 endometrial carcinomas subjected to clinical massively parallel sequencing of 410-468 cancer-related genes. Somatic mutations and CNAs (n = 238), and clinicopathologic features were determined (n = 185, initial treatment planning at our institution). TP53-mutated endometrial carcinomas encompassed uterine serous (n = 102, 55.1%), high-grade endometrial carcinoma with ambiguous features/not otherwise specified (EC-NOS; n = 44, 23.8%), endometrioid carcinomas of all tumor grades (n = 28, 15.1%), and clear cell carcinomas (n = 11, 5.9%). PTEN mutations were significantly more frequent in endometrioid carcinomas, SPOP mutations in clear cell carcinomas, and CCNE1 amplification in serous carcinomas/EC-NOS; however, none of these genomic alterations were exclusive to any given histologic type. ERBB2 amplification was present at similar frequencies across TP53-mutated histologic types (7.7%-18.6%). Although overall survival was similar across histologic types, serous carcinomas presented more frequently at stage IV, had more persistent and/or recurrent disease, and reduced disease-free survival. TP53-mutated endometrial carcinomas display clinical and molecular similarities across histologic subtypes. Our data provide evidence to suggest performance of ERBB2 assessment in all TP53-mutated endometrial carcinomas. Given the distinct clinical features of serous carcinomas, histologic classification continues to be relevant.

Abstract PO037: Identifying effective combinations of targeted therapies, using novel pre-clinical models, to improve treatment options for high-grade serous endometrial cancer

Abstract High-grade serous endometrial carcinoma (HGSEC) accounts for just 10% of endometrial cancer (EC) cases but is responsible for at least 40% of all EC-related deaths. It typically arises in post-menopausal women, with 70% of patients presenting with stage III or IV disease, does not respond to hormone therapy unlike the less aggressive forms of EC, and has a lower overall survival rate of just 18-27%, which has not improved over the past two decades. The primary treatment for HGSEC is surgery, followed by a combination of standard chemotherapies (platinum and taxane) with or without localised radiotherapy. However, recurrent HGSEC is less responsive to chemotherapy than are other subtypes of EC and even initial responses to chemotherapy are poor. Therefore, there is a great unmet clinical need to find better treatment options for women with this aggressive cancer. Apart from TP53 (mutated in up to 90% of cases), the other most frequently mutated genes in HGSEC are PPP2R1A (31%), PIK3CA (22%), FBXW7 (28%), CHD4 (17%) and BRCA2 (12%). Focal amplifications of the genes MYC, ERBB2, CCNE1, FGFR3 and SOX17 are also common. The presence of ERBB2 amplification and/or HER2 over-expression in around 30% of HGSEC suggests these patients may respond to HER2-targeting drugs, such as trastuzumab. However, only modest benefit has so far been seen for single-agent HER2-targeted therapies (ie trastuzumab or lapatinib) against HGSEC, suggesting resistance mechanisms are present. Another feature of HGSEC that could be exploited therapeutically is homologous recombination deficiency (HRD), which may be targeted with PARP inhibitors (PARPi). It is not clear what proportion of HGSEC are HRD and neither HER2-targeting drugs or PARPi have been approved for the treatment of HGSEC. Due to its rarity and a lack of pre-clinical models, HGSEC has so far been understudied, resulting in a lack of effective treatment options. We currently have 33 HGSEC patients consented to the WEHI-Stafford Fox Rare Cancer Program and have developed pre-clinical models from fresh patient tumour samples received (4 patient-derived xenograft (PDX) models validated, with 3 pending). Preliminary molecular analysis of whole-genome sequencing (5 samples, one of which gave rise to a PDX model), whole-exome sequencing (4 samples), and cancer panel sequencing (3 samples, 2 of which gave rise to PDX models; one harbouring ERBB2 amplification and one harbouring an AKT mutation) data from our HGSEC cohort has been performed. This has identified potential treatment targets, including ERBB2 amplifications and mutations in HR genes. I am using the PDX models for initial in vivo therapeutic characterization studies and to develop organoid models for use in high-throughput drug assays in vitro. This will guide subsequent novel drug combination testing in our PDX models. By combining specific targeted drugs I hope to overcome de novo resistance mechanisms and prevent acquired resistance. Results from this study will guide future decisions about therapeutic strategies to improve survival of women with HGSEC. Citation Format: Holly E. Barker, Ratana Lim, Amandine Carmagnac, Cassandra Vandenberg, Gayanie Ratnayake, Genevieve Dall, Briony Milesi, Angela Komiti, Emily O'Grady, Joshua Tram, Kym Pham Stewart, Justin Bedo, Jocelyn Penington, Joep Vissers, Sean Grimmond, Matthew Wakefield, Tony Papenfuss, Clare Scott. Identifying effective combinations of targeted therapies, using novel pre-clinical models, to improve treatment options for high-grade serous endometrial cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference: Endometrial Cancer: New Biology Driving Research and Treatment; 2020 Nov 9-10. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(3_Suppl):Abstract nr PO037.

Abstract PO026: Building the infrastructure required to research novel therapies for 35% of women with endometrial cancer who have rare subtypes

Abstract Whilst the majority of Endometrial Cancers (ECs) are common Type 1 endometrioid cancers, accounting for 75-80% of cases, with a good prognosis, Type 2 ECs include high-grade, clinically aggressive histologies, with poor response rates to hormonal therapies. Serous endometrial carcinoma is the second most common type, accounting for ~10 percent of cases, most with a p53 abnormality and a lesser proportion with HER2 overexpression/amplification/mutation. Clear cell endometrial carcinoma accounts for &amp;lt;5 % of EC, with the most aggressive cases also having p53 mutations. Mixed histologies and undifferentiated ECs are also aggressive. Carcinosarcoma (ECS) is a rare, aggressive, biphasic carcinoma that accounts for &amp;lt;5 percent of ECs, 90% with p53 abnormalities. Endometrial stromal sarcomas (ESS) can be low-grade or high-grade, or undifferentiated or resemble ovarian sex cord tumors. Uterine leiomyosarcoma (uLMS) are epithelioid or myxoid in type. Adenosarcoma involves a benign epithelial component mixed with a malignant stromal element. Whilst there have been considerable improvements in death rates for all cancers combined over the last 20 years, these improvements have not been seen for most rare cancers (RC). In order to ensure that those diagnosed with RC have access to research and novel therapies, we designed the Walter and Eliza Hall Institute of Medical Research (WEHI) Stafford Fox Rare Cancer Program (SFRCP). The WEHI-SFRCP has streamlined ethics, governance, consenting processes, including remote consent at home anywhere in Australia, and data collection protocols to allow the analysis of data and tissue of any type of RC. We have interconnected clinical and laboratory RC Databases within BioGrid Australia using the online REDCap platform. We have extensive laboratory processes in place for processing of tumour and blood samples, including the generation of PBMCs, DNA, RNA, to generate NGS including WGS; patient-derived xenografts (PDX), organoids, cell lines and other derivatives. We have high grade serous endometrial cancer (33 cases, including 4 PDX with 3 pending); uLMS (32 cases, including 2 PDX with 3 pending); endometrial carcinosarcoma (13 cases, including 3 PDX, 1 pending); rare (other, adenosarcoma, STUMP). We perform NGS testing on cases, depending on tumour purity, including Whole Genome Sequencing from fresh tumour samples; characterize PDX according to current chemotherapy and relevant novel therapeutics; study rare endometrial subtypes in specific projects and also provide information back to patients to guide therapy in the clinic. By integrating data sets with endometrial projects of similar depth we will drive forward the study of rare endometrial cancer subtypes. Citation Format: Clare L. Scott, Ratana Lim, Amandine Carmagnac, Cassandra Vandenberg, Gayanie Ratnayake, Genevieve Dall, Joshua Tram, Justin Bedo, Jocelyn Penington, Joep Vissers, Sean Grimmond, Matthew Wakefield, Anthony Papenfuss, Holly Barker. Building the infrastructure required to research novel therapies for 35% of women with endometrial cancer who have rare subtypes [abstract]. In: Proceedings of the AACR Virtual Special Conference: Endometrial Cancer: New Biology Driving Research and Treatment; 2020 Nov 9-10. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(3_Suppl):Abstract nr PO026.

Genetically Defined, Syngeneic Organoid Platform for Developing Combination Therapies for Ovarian Cancer.

The paucity of genetically informed, immunocompetent tumor models impedes evaluation of conventional, targeted, and immune therapies. By engineering mouse fallopian tube epithelial organoids using lentiviral gene transduction and/or CRISPR/Cas9 mutagenesis, we generated multiple high-grade serous tubo-ovarian cancer (HGSC) models exhibiting mutational combinations seen in patients with HGSC. Detailed analysis of homologous recombination (HR)-proficient (Trp53-/-;Ccne1OE;Akt2OE;KrasOE ), HR-deficient (Trp53-/-;Brca1-/-;MycOE ), and unclassified (Trp53-/-;Pten-/-;Nf1-/- ) organoids revealed differences in in vitro properties (proliferation, differentiation, and "secretome"), copy-number aberrations, and tumorigenicity. Tumorigenic organoids had variable sensitivity to HGSC chemotherapeutics, and evoked distinct immune microenvironments that could be modulated by neutralizing organoid-produced chemokines/cytokines. These findings enabled development of a chemotherapy/immunotherapy regimen that yielded durable, T cell-dependent responses in Trp53-/-;Ccne1OE;Akt2OE;Kras HGSC; in contrast, Trp53-/-;Pten-/-;Nf1-/- tumors failed to respond. Mouse and human HGSC models showed genotype-dependent similarities in chemosensitivity, secretome, and immune microenvironment. Genotype-informed, syngeneic organoid models could provide a platform for the rapid evaluation of tumor biology and therapeutics. SIGNIFICANCE: The lack of genetically informed, diverse, immunocompetent models poses a major barrier to therapeutic development for many malignancies. Using engineered fallopian tube organoids to study the cell-autonomous and cell-nonautonomous effects of specific combinations of mutations found in HGSC, we suggest an effective combination treatment for the currently intractable CCNE1-amplified subgroup.This article is highlighted in the In This Issue feature, p. 211.

Heterogeneity and Clonal Evolution of Acquired PARP Inhibitor Resistance in TP53- and BRCA1-Deficient Cells.

Homologous recombination (HR)-deficient cancers are sensitive to poly-ADP ribose polymerase inhibitors (PARPi), which have shown clinical efficacy in the treatment of high-grade serous cancers (HGSC). However, the majority of patients will relapse, and acquired PARPi resistance is emerging as a pressing clinical problem. Here we generated seven single-cell clones with acquired PARPi resistance derived from a PARPi-sensitive TP53 -/- and BRCA1 -/- epithelial cell line generated using CRISPR/Cas9. These clones showed diverse resistance mechanisms, and some clones presented with multiple mechanisms of resistance at the same time. Genomic analysis of the clones revealed unique transcriptional and mutational profiles and increased genomic instability in comparison with a PARPi-sensitive cell line. Clonal evolutionary analyses suggested that acquired PARPi resistance arose via clonal selection from an intrinsically unstable and heterogenous cell population in the sensitive cell line, which contained preexisting drug-tolerant cells. Similarly, clonal and spatial heterogeneity in tumor biopsies from a clinical patient with BRCA1-mutant HGSC with acquired PARPi resistance was observed. In an imaging-based drug screening, the clones showed heterogenous responses to targeted therapeutic agents, indicating that not all PARPi-resistant clones can be targeted with just one therapy. Furthermore, PARPi-resistant clones showed mechanism-dependent vulnerabilities to the selected agents, demonstrating that a deeper understanding on the mechanisms of resistance could lead to improved targeting and biomarkers for HGSC with acquired PARPi resistance. SIGNIFICANCE: This study shows that BRCA1-deficient cells can give rise to multiple genomically and functionally heterogenous PARPi-resistant clones, which are associated with various vulnerabilities that can be targeted in a mechanism-specific manner.

Anthropometric risk factors for ovarian cancer in the NIH-AARP Diet and Health Study

ObjectiveIdentifying potentially modifiable risk factors for ovarian cancer is essential for prevention because this cancer is predominantly detected at a late stage. Here, we estimated the relations of general adiposity and measures reflecting body fat distribution to the risk of epithelial ovarian cancer.MethodsWe ascertained 683 ovarian epithelial cancers (343 high-grade serous, 141 non-high grade serous) among 145,575 women, aged 50–72 years (median follow-up 12.6 years), from the National Institutes of Health—American Association of Retired Persons (NIH-AARP) Diet and Health Study. Using Cox models, we estimated confounder-adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for associations of overall ovarian cancer, high-grade serous and non-high-grade serous carcinoma with body mass index, waist circumference, hip circumference, waist–hip ratio, waist–height ratio, body adiposity index, body shape index, and abdominal volume index.ResultsAnthropometric measures were unrelated to overall ovarian cancer, high-grade serous cancer, and non-high-grade serous cancer. For example, the HR for overall ovarian cancer per standard deviation increment of body mass index at baseline was 0.98 (95% CI 0.88–1.10). Similar associations were observed with measurements of body fat distribution.ConclusionThese results do not indicate that adult adiposity is associated with ovarian cancer risk in post-menopausal women.

ROR2 Is Epigenetically Regulated in Endometrial Cancer.

Simple SummaryEndometrial cancer is one of the fastest rising cancers in women. The Wnt signalling receptor ROR2 has been shown to play distinct roles in regards to tumorigenesis in different tumour types. The aim of this study was to investigate the role of ROR2 in endometrial cancer and to determine if ROR2 expression is epigenetically regulated. Through the analyses of publicly available TCGA and GEO datasets, low ROR2 expression was correlated with unfavourable outcome and reduced overall survival of endometrial cancer patients. In addition, we observed epigenetic repression of ROR2 expression in endometrial cancer cell lines and patient samples. Ectopic expression of ROR2 in vitro inhibited the invasive ability of high grade serous endometrial cancer cells. Therefore, we concluded that ROR2 plays a tumour suppressor role in endometrial cancer and appears to be a diagnostic or therapeutic candidate.The Wnt signalling receptor ROR2 has been identified as a possible therapeutic target in numerous cancers; however, its exact role remains unclear. The aim of this study was to investigate the role of ROR2 in endometrial cancer (EC) and the potential mechanism associated with its altered expression. The association between ROR2 mRNA expression levels and clinicopathological parameters, including overall survival (OS), in EC was analysed in The Cancer Genome Atlas Uterine Corpus Endometrial Carcinoma (TCGA-UCEC) cohort and GEO dataset GSE17025. Four EC cell lines (KLE, MFE-296, Ishikawa and ARK-1) and eight clinical EC samples were analysed for ROR2 methylation via Combined Bisulphite Restriction Analysis (COBRA) and bisulphite genomic sequencing (BGS). In addition, the functional effects of ROR2 overexpression were investigated in Ishikawa and ARK-1 cells following ectopic ROR2 expression. ROR2 promoter methylation or reduced ROR2 expression were both found to correlate with shorter OS, high grade and serous subtype in the TCGA-UCEC and GEO datasets. ROR2 was epigenetically silenced by promoter methylation in both patient samples and cell lines. A significant correlation between ROR2 expression levels and promoter methylation was observed in patient samples (r = −0.797, p = 0.018). ROR2 restoration in ARK-1 significantly decreased invasion ability, with associated changes in epithelial-mesenchymal transition (EMT) markers. ROR2 plays a tumour-suppressor role in EC and is epigenetically suppressed with the development of disease. It may represent a diagnostic or therapeutic candidate for EC.

The RAD51D c.82G>A (p.Val28Met) variant disrupts normal splicing and is associated with hereditary ovarian cancer.

Mutations in RAD51D are associated with a predisposition to primary ovarian, fallopian tube, and peritoneal carcinoma. Our study aims to characterize a RAD51D missense variant in a hereditary ovarian cancer family. The effects of the RAD51D c.82G>A (p.Val28Met) variant on mRNA splicing were evaluated and characterized using RT-PCR, cloning and DNA sequencing. This variant completely disrupts normal splicing and results in the loss of 3'end of 5'UTR and the entire exon 1 (c.-86_c.82), which presumably leads to loss of the RAD51D protein. The RAD51D c.82G>A (p.Val28Met) variant is clinically significant and classified as likely pathogenic. Our results indicate that the RAD51D c.82G>A (p.Val28Met) variant contributes to cancer predisposition through disruption of normal mRNA splicing. The identification of this variant in an individual affected with high-grade serous fallopian tube cancer suggests that the RAD51D variant may contribute to predisposition to the ovarian cancer in this family.

PAX8, an Emerging Player in Ovarian Cancer.

Ovarian Cancer is one of the most lethal and widespread gynecological malignancies. It is the seventh leading cause of all cancer deaths worldwide. High-Grade Serous Cancer (HGSC), the most commonly occurring subtype, alone contributes to 70% of all ovarian cancer deaths. This is mainly attributed to the complete lack of symptoms during the early stages of the disease and absence of an early diagnostic marker.PAX8 is emerging as an important histological marker for most of the epithelial ovarian cancers, as it is expressed in about 90% of malignant ovarian cancers, specifically in HGSC. PAX8 is a member of the Paired-Box gene family (PAX1-9) of transcription factors whose expression is tightly controlled temporally and spatially. The PAX genes are well known for their role in embryonic development and their expression continues to persist in some adult tissues. PAX8 is required for the normal development of Müllerian duct that includes Fallopian tube, uterus, cervix, and upper part of vagina. In adults, it is expressed in the Fallopian tube and uterine epithelium and not in the ovarian epithelium. Considering the recent studies that predict the events preceding the tumorigenesis of HGSC from the Fallopian tube, PAX8 appears to have an important role in the development of ovarian cancer.In this chapter, we review some of the published findings to highlight the significance of PAX8 as an important marker and an emerging player in the pathogenesis of ovarian cancer. We also discuss regardingthe future perspectives of PAX8wherein itcould contribute to the betterment of ovarian cancer diagnosis and treatment.

History of intraperitoneal platinum drug delivery for ovarian cancer and its future applications

Intraperitoneal (IP) delivery of cisplatin was developed in the 1970s based on a strong pharmacologic rationale and rodent models. Its advantage over intravenous (IV) administration was supported initially by observational studies in treating recurrent ovarian cancer and eventually by better outcomes from IP vs. IV cisplatin in randomized studies in patients undergoing optimal surgical debulking at diagnosis. In the past two decades, with the introduction of novel anticancer interventions (such as taxanes, bevacizumab, inhibitors of DNA repair, and immune check point inhibitors), advantages of IP drug delivery are less clear and concerns are raised on cisplatin's therapeutic index. The discovery of BRCA genes and their key role in DNA repair, on the other hand, have strengthened the rationale for IP drug delivery: high grade serous cancers arising in the Mullerian epithelium in association with hereditary or somatic BRCA function inactivation are linked to peritoneal spread of cells that - while initially sensitive - are prone to emergence of platinum resistance. Therefore, selection of patients based on genomic features and focusing on the better tolerated IP carboplatin are ongoing. Recent examples of leveraging the peritoneal route include (1) targeting the cell membrane copper transport receptor - that is shared by platinums - by the combination of the proteasome inhibitor bortezomib and IP carboplatin; and (2) enhancing IP 5-fluoro-2-deoxyuridine cytotoxicity when coupled with PARP inhibition.

Propensity score matching confirms that primary surgery or neoadjuvant chemotherapy result in equivalent survival within a comprehensive cohort of patients with high-grade serous ovarian cancer

ObjectiveOur objective was to investigate whether trial evidence showing that neoadjuvant chemotherapy is non inferior to primary surgery for the primary treatment of advanced ovarian cancer could be extrapolated to groups of patients that were not included in the trials. MethodsUsing a detailed retrospective cohort of all patients managed through a single tertiary hospital we carried out a propensity score analysis, principal component analysis, and cox proportional hazard analysis to compare survival in matched cohorts. ResultsA propensity score analysis showed that for at least 41% of all patients with advanced high-grade serous cancer neoadjuvant chemotherapy is non inferior to primary surgery (median survival primary surgery: 38 months, neoadjuvant chemotherapy: 35 months. P = 0.39). However, principal component analysis, supported by cox modelling, suggests that for some subgroups, including patients with subdiaphragmatic nodal disease, primary surgery may be associated with improved survival (HR 0.11, CI 0.026–0.48). ConclusionsWe have shown that the findings of previous trials can be extrapolated to a wider population and that statistical modelling can be used to identify groups or patients who benefit from specific modalities of treatment.