High-grade Serous Ovarian Cancer Cases Research Articles

Abstract 5622: Uncovering the transcriptional regulation of TPPP3

Abstract Tubulin Polymerization Promoting Protein 3 (TPPP3) is a protein coding gene primarily associated with microtubule bundling. However more recent research is beginning to reveal more diverse roles it may play in the cell, including B-catenin signaling and endothelial injury. TPPP3 has also been associated with increased cancer growth and proliferation as well epithelial to mesenchymal transition. However, it is unknown how TPPP3 is regulated. We used high grade serous ovarian cancer (HGSOC) as a model to uncover the regulation of TPPP3 as it is highly expressed in many HGSOC cases. To start, we downloaded ~500 HGSOC RNA-seq datasets from The Cancer Genome Atlas (TCGA) and, using python, created a co-expression network to identify a subset of genes exhibiting expression patterns correlated with TPPP3 across all datasets, resulting in the identification of 222 genes. Dynein arm assembly, cilia movement and assembly, and microtubule movement and structure were among the top GO-terms after gene ontology analysis. The genes associated with these processes are typically upregulated in the fallopian tube tissue which aligns with the fact that a majority of HGSOCs originate in the fallopian tube. Fork-head box J1 (FOXJ1) is a transcription factor associated with ciliogenesis and was among the top 222 genes from the co-expression network. It has not been confirmed to transcriptionally regulate TPPP3, but their expression patterns line up across many tissue types. In addition, the TPPP3 promoter contains an RFX2 binding site. RFX2 is DNA binding protein that FOXJ1 uses as a scaffold to bind to proximal promoters due to it binding at to DNA at a distal location. As a result of this evidence, we hypothesize that FOXJ1 transcriptionally regulates TPPP3 via RFX2. To test this hypothesis, we inhibited FOXJ1 and identified TPPP3 downregulation. We are further investigating the regulatory function of how TPPP3 is regulated. Citation Format: James W. Lord, Dmitry Leshchiner, Sachi Horibata. Uncovering the transcriptional regulation of TPPP3 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5622.

Abstract A040: Improving specificity for ovarian cancer screening using a novel extracellular vesicle-based blood test

Abstract Introduction: The low incidence of ovarian cancer (OC) in average risk individuals dictates any OC screening method needs to be both highly sensitive and highly specific. Even using the multimodal OC screening strategy combining longitudinal serum CA125 and transvaginal ultrasound, 16% of OCs were not detected and false positives due to benign ovarian tumors, which are 5-10 times more prevalent than OC, remained high. Due to lack of mortality benefit, population screening is still not recommended. We hypothesized that detecting multiple colocalized protein or glycosylation epitopes (PGEs) on single tumor-derived extracellular vesicles (EVs) would increase specificity and sensitivity for detection of OC. Methods: The Mercy Halo™ OC test employs immunoaffinity capture and proximity-ligation qPCR to detect combinations of up to 3 PGE biomarkers to maximize specificity and measures multiple combinations to maximize sensitivity. We selected 3 PGE combinations to form a panel test to distinguish high-grade serous ovarian cancer (HGSC) from benign ovarian tumors and normal patients and compared performance of our test to CA125. We used a case-control training set from university-associated Canadian biobanks comprised of EDTA plasma from 124 healthy controls, 89 HGSC cases (17 Stage I, 35 Stage II, 37 Stage III)(10 BRCA+), and 192 benign adnexal masses to lock down the test, the data interpretation algorithm, and the cut-off between cancer and non-cancer. Performance was verified in an independent blinded diagnostic case-control set of 397 serum samples from 138 healthy controls, 111 benign adnexal masses, 20 borderlines, 66 HGSC and 62 non-HGSC from the UK Ovarian Cancer Population Study. For comparison, a CA125 ELISA was run for all samples in both studies. Results: Using the locked assay, algorithm, and cut-off established in the training cohort, our test showed a specificity in healthy controls of 92.8% (128/138; 95% CI: 0.87-0.96), a sensitivity in HGSC of 97.0% (64/66; 95% CI: 0.90-0.99), and an AUC of 0.92 (95% CI 0.89-0.95) in the verification cohort. We correctly identified 11/13 Stage I and all 54 Stage II/III/IV HGSC cases. Our test also detected 76.8% (63/82) of the borderline and non-HGSC histotypes. CA125 detected 92.4% (61/66) of the HGSC cases and 84.1% (69/82) of the borderlines and non-HGSC. The greatest improvement in test performance relative to CA125 was seen with benign adnexal masses. In the verification cohort 35.1% (39/111) of the benign samples were CA125 positive compared to 21.6% (24/111) with our test. This reduction in false positives was seen across 10 benign histotypes tested. Conclusions: These results demonstrate that our test using colocalized PGEs on EVs can detect OC, especially HGSC, in both plasma and serum with high sensitivity and specificity. The combinations of 5 biomarkers rather than CA125 alone also decreased benign false positives. The test performance suggests that our test may be useful in average and/or high-risk ovarian cancer screening. Future studies will explore this in asymptomatic populations. Citation Format: Emily S. Winn-Deen, Sanchari Banerjee, Daniel Gusenleitner, Laura T. Bortolin, Jonian Grosha, Kelly M. Biette, Karen Copeland, Christopher R. Sedlak, Bilal Hamzeh, Anthony D. Couvillon, Delaney M. Byrne, Peter A. Duff, Lauren T. Cuoco, MacKenzie S. King, Aleksandra Gentry-Maharaj, Sophia Apostolidou, Dawn R. Mattoon, Christine D. Berg, David F. Ransohoff, Steven J. Skates, Usha Menon. Improving specificity for ovarian cancer screening using a novel extracellular vesicle-based blood test [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A040.

Insights for precision oncology from the integration of genomic and clinical data of 13,880 tumors from the 100,000 Genomes Cancer Programme

The Cancer Programme of the 100,000 Genomes Project was an initiative to provide whole-genome sequencing (WGS) for patients with cancer, evaluating opportunities for precision cancer care within the UK National Healthcare System (NHS). Genomics England, alongside NHS England, analyzed WGS data from 13,880 solid tumors spanning 33 cancer types, integrating genomic data with real-world treatment and outcome data, within a secure Research Environment. Incidence of somatic mutations in genes recommended for standard-of-care testing varied across cancer types. For instance, in glioblastoma multiforme, small variants were present in 94% of cases and copy number aberrations in at least one gene in 58% of cases, while sarcoma demonstrated the highest occurrence of actionable structural variants (13%). Homologous recombination deficiency was identified in 40% of high-grade serous ovarian cancer cases with 30% linked to pathogenic germline variants, highlighting the value of combined somatic and germline analysis. The linkage of WGS and longitudinal life course clinical data allowed the assessment of treatment outcomes for patients stratified according to pangenomic markers. Our findings demonstrate the utility of linking genomic and real-world clinical data to enable survival analysis to identify cancer genes that affect prognosis and advance our understanding of how cancer genomics impacts patient outcomes.

Ovarian Cancer: From Precursor Lesion Identification to Population-Based Prevention Programs.

Epithelial ovarian cancer (EOC) is a heterogeneous group of malignancies, including high-grade serous ovarian cancer (HGSC). HGSC is often diagnosed at advanced stages and is linked to TP53 variants. While BRCA variants elevate risk, most HGSC cases occur in individuals without known genetic variants, necessitating prevention strategies for people without known high-risk genetic variants. Effective prevention programs are also needed due to the lack of traditional screening options. An emerging primary prevention strategy is opportunistic salpingectomy, which involves removing fallopian tubes during another planned pelvic surgery. Opportunistic salpingectomy offers a safe and cost-effective preventative option that is gaining global adoption. With the publication of the first cohort study of patients who underwent salpingectomy, specifically for cancer prevention, attention has turned to broadening opportunities for salpingectomy in addition to more targeted approaches. Prevention opportunities are promising with increasing adoption of salpingectomy and the increased understanding of the etiology of the distinct histotypes of ovarian cancer. Yet, further research on targeted risk-reducing salpingectomy with thoughtful consideration of equity is necessary to reduce death and suffering from ovarian cancer.

A multimodal radiomic machine learning approach to predict the LCK expression and clinical prognosis in high-grade serous ovarian cancer

We developed and validated a multimodal radiomic machine learning approach to noninvasively predict the expression of lymphocyte cell-specific protein-tyrosine kinase (LCK) expression and clinical prognosis of patients with high-grade serous ovarian cancer (HGSOC). We analyzed gene enrichment using 343 HGSOC cases extracted from The Cancer Genome Atlas. The corresponding biomedical computed tomography images accessed from The Cancer Imaging Archive were used to construct the radiomic signature (Radscore). A radiomic nomogram was built by combining the Radscore and clinical and genetic information based on multimodal analysis. We compared the model performances and clinical practicability via area under the curve (AUC), Kaplan–Meier survival, and decision curve analyses. LCK mRNA expression was associated with the prognosis of HGSOC patients, serving as a significant prognostic marker of the immune response and immune cells infiltration. Six radiomic characteristics were chosen to predict the expression of LCK and overall survival (OS) in HGSOC patients. The logistic regression (LR) radiomic model exhibited slightly better predictive abilities than the support vector machine model, as assessed by comparing combined results. The performance of the LR radiomic model for predicting the level of LCK expression with five-fold cross-validation achieved AUCs of 0.879 and 0.834, respectively, in the training and validation sets. Decision curve analysis at 60 months demonstrated the high clinical utility of our model within thresholds of 0.25 and 0.7. The radiomic nomograms were robust and displayed effective calibration. Abnormally high expression of LCK in HGSOC patients is significantly correlated with the tumor immune microenvironment and can be used as an essential indicator for predicting the prognosis of HGSOC. The multimodal radiomic machine learning approach can capture the heterogeneity of HGSOC, noninvasively predict the expression of LCK, and replace LCK for predictive analysis, providing a new idea for predicting the clinical prognosis of HGSOC and formulating a personalized treatment plan.

Speculation on optimal numbers of examined lymph node for early-stage epithelial ovarian cancer from the perspective of stage migration.

In early-stage epithelial ovarian cancer (EOC), how to perform lymphadenectomy to avoid stage migration and achieve reliable targeted excision has not been explored in depth. This study comprehensively considered the stage migration and survival to determine appropriate numbers of examined lymph node (ELN) for early-stage EOC and high-grade serous ovarian cancer (HGSOC). From the Surveillance, Epidemiology, and End Results database, we obtained 10372 EOC cases with stage T1M0 and ELN ≥ 2, including 2849 HGSOC cases. Generalized linear models with multivariable adjustment were used to analyze associations between ELN numbers and lymph node stage migration, survival and positive lymph node (PLN). LOESS regression characterized dynamic trends of above associations followed by Chow test to determine structural breakpoints of ELN numbers. Survival curves were plotted using Kaplan-Meier method. More ELNs were associated with more node-positive diseases, more PLNs and better prognosis. ELN structural breakpoints were different in subgroups of early-stage EOC, which for node stage migration or PLN were more than those for improving outcomes. The meaning of ELN structural breakpoint varied with its location and the morphology of LOESS curve. To avoid stage migration, the optimal ELN for early-stage EOC was 29 and the minimal ELN for HGSOC was 24. For better survival, appropriate ELN number were 13 and 8 respectively. More ELNs explained better prognosis only at a certain range. Neither too many nor too few numbers of ELN were ideal for early-stage EOC and HGSOC. Excision with appropriate numbers of lymph node draining the affected ovary may be more reasonable than traditional sentinel lymph node resection and systematic lymphadenectomy.

Using chemotherapy response by KELIM score to predict response to first line maintenance PARP inhibitor therapy in non-BRCA mutant/homologous recombination deficiency (HRD) unknown high grade serous ovarian cancer (HGSOC).

e17547 Background: Maintenance PARP inhibitor therapy after response to first line chemotherapy is now standard of care in advanced HGSOC. Niraparib is available to all patients based on the PRIMA trial data; however, the progression free survival (PFS) benefit for patients without BRCA mutations or homologous recombination deficiency (HRD) is limited. Funded HRD testing is not accessible in many countries. Patient selection for PARPi therapy in non-BRCA mutant HGSOC is challenging. The calculated CA-125 ELIMination of Rate Constant K (KELIM) score is a mathematical model developed to evaluate CA-125 kinetics during chemotherapy. KELIM has been shown to correlate with chemosensitivity, with scores ≥1 associated with better clinical outcomes. This project aims to use real-world patient data to assess if surrogate markers, such as KELIM score and/or pathological chemotherapy response score, can predict response to 1st line maintenance PARPi in the absence of funded HRD testing. Methods: A retrospective review of non-BRCA mutant HGSOC cases on first line maintenance PARPi therapy at BC Cancer, Canada between April 2020 and June 2022. Only cases confirmed to be non-BRCA mutant (by both germline and tumour testing) were included in the study. Data collection was through electronic medical records and included patient demographics, chemotherapy intent (neoadjuvant vs. adjuvant), pathological (p) chemotherapy response score (CRS), progression-free survival (PFS) defined as start of niraparib to radiological evidence of disease progression. PFS analysis was performed in all patients provided 1 full cycle had been completed. The rate of not progressing at 12 months (PFS12) was calculated. KELIM score was calculated from at least 3 CA125 values taken within 100 days from the chemotherapy start date and using a validated calculation software. Results: 70 patients met the full eligibility criteria for analysis. All patients received niraparib as PARPi therapy. Mean age was 67 years and 40 patients (57%) were ≥ 65 years. Most patients were FIGO stage 3C at presentation (56%). Median number of niraparib cycles was 10 (range 1-28). 35/70 patients (50%) had disease progression at time of data analysis with a median follow-up of 13.2 months. 59 patients had evaluable KELIM scores. pCRS was not associated with any statistically significant differences in PFS. Patients with KELIM scores ≥1 had a trend to greater PFS from niraparib vs. those with KELIM <1 with median PFS of 15 months vs. 8.3 months respectively ( p=0.06). PFS12 rate was higher at 64% with KELIM scores ≥1 vs. 43% with KELIM <1; ( p=0.18). Conclusions: We show that KELIM score could be a useful tool to predict PARP inhibitor response and aid clinical decision-making by oncologists and patients in the real world setting where HRD testing is unfunded.

Abstract 3506: High-grade serous ovarian cancer somatic mutational signatures in Black and White individuals

Abstract Causes of racial disparities in ovarian cancer survival are likely multifactorial, including socio-environmental, structural, and biological factors. Mutational signatures reflect endogenous and exogenous exposures, which may differ by race and ethnicity. This study aims to characterize mutational signatures and their associated etiologies among Black high-grade serous ovarian cancer (HGSC) cases, and to compare the occurrence and distribution of signatures with White TCGA cases. Mutational profiling with whole exome sequencing in matched blood and tumor formalin-fixed paraffin-embedded specimens was performed in 271 HGSC cases identifying as Black or African American and participating in the African American Cancer Epidemiology Study (AACES) or the North Carolina Ovarian Cancer Study (NCOCS). After filtering, we identified 28,601 high-confidence coding mutations in 256 samples that passed quality control assessments. The median number of mutations per sample was 67, similar to that in TCGA at 66. Mutation frequencies of the major genes identified in TCGA were nearly identical in Black AACES/NCOCS cases; mutations in TP53 were present in 96% and 89%, respectively, and mutation frequencies in BRCA1/2, CSMD3, NF1, CDK12, FAT3, GABRA6, and RB1 differed by only 0-2%. We performed mutational signature analysis using SigProfiler and refitting to the Catalogue of Somatic Mutations in Cancer (COSMIC) previously published single base-pair substitution (SBS) signatures reflecting mutational processes resulting from known endogenous and exogenous exposures. SBS signatures are defined by 96 mutation features including the single nucleotide variant class (e.g., C>A, C>G, C>T, T>A, T>C, and T>G) and the identity of the 5’/3’ flanking bases. We observed much higher frequencies of the mismatch repair deficiency, homologous recombination deficiency, ultraviolet light, and treatment exposure signatures in Black AACES/NCOCS cases (26%, 22%, 9%, and 8%, respectively) than in White TCGA cases (3%, 10%, 3%, and 2%, respectively). The frequencies of the remaining signatures with known etiologies (clock-like, reactive oxygen species, base excision repair, mutagen exposure, DNA polymerase epsilon, and tobacco signatures) differed by less than 5% between Black and White cases. Many mismatch repair deficiency signatures identified in Black AACES/NCOCS cases are dominated by C>T or T>C mutations and may represent an artifact from formalin fixation. While we observed that the somatic mutation frequencies in major genes associated with HGSC were similar in Black and White cases, the frequencies of some known mutational signatures were considerably higher in Black HGSC. In particular, despite similar frequencies of BRCA1/2 mutations, the homologous recombination deficiency signature was considerably more common in Black than White HGSC. Citation Format: Katherine A. Lawson-Michod, David Nix, Lindsay Collin, Natalie Davidson, Ariel Hippen, Chad Huff, Aaron Atkinson, Lucas A. Salas, Lauren Peres, Casey Greene, Joellen Schildkraut, Jeffrey Marks, Jennifer A. Doherty. High-grade serous ovarian cancer somatic mutational signatures in Black and White individuals [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3506.

Extracellular matrix in high-grade serous ovarian cancer: Advances in understanding of carcinogenesis and cancer biology.

High-grade serous ovarian cancer (HGSOC) is notoriously known as the "silent killer" of post-menopausal women as it has an insidious progression and is the deadliest gynaecological cancer. Although a dual origin of HGSOC is now widely accepted, there is growing evidence that most cases of HGSOC originate from the fallopian tube epithelium. In this review, we will address the fallopian tube origin and involvement of the extracellular matrix (ECM) in HGSOC development. There is limited research on the role of ECM at the earliest stages of HGSOC carcinogenesis. Here we aim to synthesise current understanding of the contribution of ECM to each stage of HGSOC development and progression, beginning at serous tubal intraepithelial carcinoma (STIC) precursor lesions and proceeding across key events including dissemination of tumourigenic fallopian tube epithelial cells to the ovary, survival of these cells in peritoneal fluid as multicellular aggregates, and colonisation of the ovary. Likewise, as part of the metastatic series of events, serous ovarian cancer cells survive travel in peritoneal fluid, attach to, migrate across the mesothelium and invade into the sub-mesothelial matrix of secondary sites in the peritoneal cavity. Halting cancer at the pre-metastatic stage and finding ways to stop the dissemination of ovarian cancer cells from the primary site is critical for improving patient survival. The development of drug resistance also contributes to poor survival statistics in HGSOC. In this review, we provide an update on the involvement of the ECM in metastasis and drug resistance in HGSOC. Interplay between different cell-types, growth factor gradients as well as evolving ECM composition and organisation, creates microenvironment conditions that promote metastatic progression and drug resistance of ovarian cancer cells. By understanding ECM involvement in the carcinogenesis and chemoresistance of HGSOC, this may prompt ideas for further research for developing new early diagnostic tests and therapeutic strategies for HGSOC with the end goal of improving patient health outcomes.

Genetic analysis of heterogeneous subsets of circulating tumour cells from high grade serous ovarian carcinoma patients

Circulating tumour cells (CTCs) are heterogenous and contain genetic information from the tumour of origin. They bear specific intra- and extra-cellular protein markers aiding in their detection. However, since these markers may be shared with other rare cells in the blood, only genetic testing can confirm their malignancy. Herein, we analyse different CTC subsets using single cell whole genome DNA sequencing to validate their malignant origin. We randomly selected putative CTCs identified by immunostaining that were isolated from 4 patients with high grade serous ovarian cancer (HGSOC) and one with benign cystadenoma. We specifically targeted CTCs positive for epithelial (CK/EpCAMpos), mesenchymal (vimentinpos), and pseudoendothelial (CK/EpCAMpos plus CD31pos) markers. We isolated these cells and performed whole genome amplification (WGA) and low-pass whole-genome sequencing (LP-WGS) for analysis of copy number alterations (CNA). Of the CK/EpCAMpos cells analysed from the HGSOC patients, 2 of 3 cells showed diverse chromosomal CNAs. However, the 4 pseudoendothelial cells (CK/EpCAMpos plus CD31pos) observed in the HGSOC cases did not carry any CNA. Lastly, two of the clusters of vimentin positive cells sequenced from those found in the benign cystadenoma case had CNA. Despite the low number of cells analysed, our results underscore the importance of genetic analysis of putative CTCs to confirm their neoplastic origin. In particular, it highlights the presence of a population of CK/EpCAMpos cells that are not tumour cells in patients with HGSOC, which otherwise would be counted as CTCs.

FGF19 promotes cell autophagy and cisplatin chemoresistance by activating MAPK signaling in ovarian cancer.

Chemotherapy is one of the primary treatments for ovarian cancer patients. Autophagy has been linked to chemotherapy resistance in tumor cells. Recent studies have suggested that fibroblast growth factor 19 (FGF19) may be involved in the onset and progression of malignancies. However, the relationship between FGF19 and autophagy in ovarian cancer is still unknown. Next-generation sequencing (NGS) was conducted to analyze gene mutation profiles of 62 cases of high grade serous ovarian cancer (HGSOC). Fluorescence in situ hybridization (FISH) was performed to validate the amplification of FGF19 in HGSOC tissues. Quantitative PCR (qPCR) and immunohistochemistry (IHC) were used to analyze the difference of FGF19 in mRNA and protein expression. Meanwhile, bioinformatics techniques were used to analyze the expression profiles of FGF19 and the correlation with prognosis. Besides, immunofluorescence, transmission electron microscopy and Cell Counting Kit 8 (CCK-8) were used to investigate the potential mechanisms. In this study, we found that FGF19 promotes cisplatin resistance in ovarian cancer cells by inducing autophagy. NGS analysis of 62 HGSOC cases identified a significantly amplified gene, FGF19. In addition, the expression level of FGF19 in ovarian cancer samples was higher than that in normal samples. FISH results showed a positive correlation between amplification and expression of FGF19. Knockdown of FGF19 inhibited the cell autophagy through decrease in the expression of LC3 and Beclin 1, and increase in the expression of SQSTM1/p62. Furthermore, we observed that p38 MAPK phosphorylation was down-regulated after FGF19 knockdown. IFN-γ, a potential p38 MAPK activator, counteracted the inhibition of cell autophagy and the anti-proliferation effect of cisplatin induced by FGF19 knockdown in ovarian cancer cells. FGF19 increases autophagy and chemoresistance in ovarian cancer by activating the p38 MAPK pathway. These results could point to FGF19 being a potential therapeutic target for ovarian cancer.

Uterine Cavity Lavage Mutation Analysis in Lithuanian Ovarian Cancer Patients.

Type II ovarian cancer (OC) is generally diagnosed at an advanced stage, translating into a poor survival rate. Current screening methods for OC have failed to demonstrate a reduction in mortality. The uterine lavage technique has been used to detect tumor-specific TP53 mutations from cells presumably shed from high-grade serous ovarian cancer (HGSOC). We aimed to pilot whether the detection of TP53 mutation in uterine cavity lavage can be used as a diagnostic method for HGSOC using an expanded gene panel. In this study 90, uterine lavage and 46 paired biopsy samples were analyzed using next-generation sequencing (NGS) targeting TP53 as well as five additional OC-related genes: BRCA1, BRCA2, PI3KCA, PTEN, and KRAS. Uterine lavage was successfully applied to all patients, and 56 mutations were detected overall. TP53 mutations were detected in 27% (10/37) of cases of type HGSOC; BRCA1 and BRCA2 mutations were also frequent in this group (46%; 17/37). Overall concordance between tissue and liquid biopsy samples was 65.2%. Uterine lavage TP53 mutations in combination with other biomarkers could be a useful tool for the detection of lowly invasive HGSOC.

Abstract P030: Prospective analysis of plasma metabolites for early detection of high-grade serous ovarian cancer

Abstract Background: Ovarian cancer has poor prognosis due to >60% of the patients being diagnosed at late-stage. However, there is currently no ovarian cancer biomarker appropriate for screening. This may be, in part, due to many prior studies using clinical samples obtained at the time of diagnosis for biomarker discovery. Here, we sought to discover novel plasma metabolomic biomarkers for ovarian cancer early detection using prospectively collected blood samples. Methods: We examined 250 plasma metabolites in 93 high-grade serous ovarian cancer (HGSOC) cases with blood drawn up to five years prior to diagnosis and 93 matched controls in the prospective Nurses’ Health Studies and Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. We also measured metabolites in 40 early-stage HGSOC cases with blood collected at diagnosis and 40 matched controls in a hospital-based study. We used conditional logistic regression to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of the association between one standard deviation increase in metabolite levels and ovarian cancer risk, and used metabolite set enrichment analysis (MSEA) to identify metabolite group associations. False discovery rate (FDR) was used to correct for multiple testing. For the prospectively collected blood samples, we conducted analyses by time between blood draw and diagnosis. Results: Plasma metabolites associated with ovarian cancer in blood samples collected prospectively were different than in blood samples collected at diagnosis of early-stage disease compared to controls. There were 45 individual metabolites associated with early-stage disease (FDR<0.05), and none of these metabolites were associated with ovarian cancer in the prospectively collected blood samples (FDR<0.05). There were 10 metabolites associated with ovarian cancer diagnosed within 3 years of blood collection (p<0.05), including 7 lipid metabolites (2 lysophosphatidylcholines, 2 diglycerides, 1 phosphatidylcholine, 1 cholesteryl esters, 1 phosphatidylethanolamines) that were inversely associated with ORs ranging from 0.61-0.66. Interestingly, the direction of association remained similar when restricting to cases with blood collected up to 2 years and 1 year prior to diagnosis, and the magnitude of association generally became stronger for cases closer to diagnosis. Similarly, distinct profiles were observed in MSEA, with diglycerides being inversely associated with ovarian cancer diagnosis in prospectively collected blood samples (FDR ranging from <0.05 to <0.20) and positively associated in blood collected at early-stage disease diagnosis (FDR<0.05).Conclusion: Our results revealed plasma metabolomic profiles differ between prospectively collected blood samples up to 3 years prior to diagnosis and blood samples collected at time of diagnosis, even for early-stage disease, suggesting the use of prospectively collected blood samples may discover promising novel early detection biomarkers for ovarian cancer. Citation Format: Naoko Sasamoto, Oana A. Zeleznik, Allison F. Vitonis, Daniel W. Cramer, Julian Avila-Pacheco, Clary B. Clish, Britton Trabert, Shelley S. Tworoger, Kathryn L. Terry. Prospective analysis of plasma metabolites for early detection of high-grade serous ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P030.

Editorial: Towards better and personalized management of ovarian cancer in China

Ovarian cancer remains the most lethal gynaecological malignancy worldwide, with 313 959 newly diagnosed cases and 207 252 deaths annually; approximately one-sixth of which occur in China.1 Despite the advances in the treatment of ovarian cancer, its 5-year survival rate has not surpassed 45%.2 In this supplement to the British Journal of Obstetrics and Gynaecology, eight manuscripts that focus on ovarian cancer therapy efficacy and consequences, therapeutic and prognostic biomarkers, shifts in treatment patterns, and establishment of big data gynaecological oncology platforms are included to outline the recent advances in our understanding of ovarian cancer management in China. Primary debulking surgery (PDS) followed by chemotherapy or neoadjuvant chemotherapy (NACT) and then interval debulking surgery (IDS) has been the standard of care for advanced epithelial ovarian cancer (EOC), and the absence of residual tumour after surgery is an important determinant of survival. Sun et al. summarised EOC-targeted fluorescent probes and open-field fluorescence imaging strategies to eradicate submillimetre and intraperitoneally scattered tumour masses to achieve complete resection. However, complete resection does not benefit all ovarian cancer subtypes. Liu et al. conducted a multicentre retrospective study and revealed that omentectomy did not improve survival and had no impact on pregnancy or live birth rates in apparently early malignant ovarian germ cell tumours. Therefore, prospective clinical trials are required to validate our conclusions. Intraperitoneally scattered tumour masses of ovarian cancer provide a rationale for the utilisation of intraperitoneal chemotherapy (IP). However, current randomised clinical trials failed to demonstrate the survival benefits of IP.3 Xiang et al. took advantage of the follow-up population of the AICE trial4 to conduct a treatment-free survival (TFS) analysis and demonstrated that patients with high tumour burden achieved significantly longer TFS and quality-adjusted overall survival (OS) compared with their counterparts with low tumour load when treated with IP followed by intravenous chemotherapy. Hyperthermic IP (HIPEC) after PDS improved the survival of EOC,5 but HIPEC in the neoadjuvant setting (NHIPEC) has not been sufficiently studied. Wu et al. demonstrated that NHIPEC plus NACT resulted in significantly prolonged progression-free survival (PFS) compared with NACT alone in patients with advanced high-grade serous ovarian cancer (HGSOC) in a retrospective study. Approximately 50% of HGSOC cases suffer from homologous recombination deficiency (HRD), which enables synthetic lethality with poly (ADP-ribose) polymerase (PARP) inhibition. Yuan et al. constructed a genomic scar model to predict HRD using machine learning algorithms, which demonstrated a sensitivity over 97% in detecting BRCA-deficient events and exhibited robustness in identifying responders to PARP inhibitors (PARPi). Treatment-naïve ovarian cancer often has a high response rate to platinum-based chemotherapy; however, platinum resistance inevitably emerges. Wu et al. revealed that co-expression of SLC7A11 and GPX4, two pivotal ferroptosis-related proteins, is significantly associated with platinum resistance and predicts worse PFS and OS. Liu et al. investigated the association among the primary treatment sequence (PDS versus NACT-IDS), recurrence characteristics, and post-relapse survival (PRS) based on real-world evidence. NACT-IDS was revealed as an independent risk factor for decreased PRS and was significantly associated with a shortened progression-free interval and a diffuse pattern of recurrence. China has the largest gynaecological oncology population worldwide and produces tremendous quantities of real-world disease- and treatment-related data. Zeng et al. established the National Union of Real-world Gynecological Oncology Research and Patient Management Platform (NUWA platform), the first large, scalable longitudinal clinico-genomic database in China that integrates multidimensional data on gynaecological oncology. They presented the implementation status and quality control methodology of the platform and leveraged the currently available data derived from 11 456 patients with ovarian cancer to display treatment pattern shifts in recent years. We are grateful to all the authors for their contributions and to British Journal of Obstetrics and Gynaecology for publishing this special issue. We believe that the contents of this issue will help readers understand the efforts of Chinese clinicians and researchers to facilitate better and personalised management of ovarian cancer in China.

High expression of CD8 in the tumor microenvironment is associated with PD-1 expression and patient survival in high-grade serous ovarian cancer.

Objective:The current study assesses programmed death-1 (PD-1) receptor expression and CD3, CD4, and CD8 tumor-infiltrating lymphocytes (TILs) in high-grade serous ovarian cancer (HGSOC) and associates our results with neoadjuvant chemotherapy history and disease prognosis.Materials and Methods:We included cases diagnosed with primary HGSOC with biopsy or surgical resection materials in this study. The immunoreactivity of CD3, CD4, CD8, and PD1 was assessed immunohistochemically in tumor tissue. We analyzed TILs in two predetermined groups of high and low TIL. The relationships between clinical characteristics, PD-1, and TIL were assessed. by the χ(2) test or Fisher’s Exact test. We used Kaplan-Meier survival analysis and Cox proportional hazards regression model to the connection between survival and the amounts of TIL, and PD1.Results:Univariate analysis demonstrated that optimal debulking (p<0.001), early International Federation of Gynecology and Obstetrics stage (p=0.046), and higher scores of stromal CD8+ TIL expression (p=0.028) in tumor cells were all substantially correlated with longer disease-free survival (DFS), whereas the remaining variables analyzed, including PD-1 positivity, stromal CD3+, and CD4+ TILs, and intraepithelial CD3+, CD4+, and CD8+ TILs, were not correlated with DFS. Also, univariate analysis revealed that optimal debulking (p=0.010), and higher scores of stromal CD8+ TIL expression (p=0.021) in tumor cells were all substantially correlated with longer overall survival (OS).Conclusion:Higher scores of stromal CD8+ TILs are substantially correlated with DFS and OS in univariate analyses, whereas scores of stromal CD3+ and CD4+ TILs, and intraepithelial CD3+, CD4+, and CD8+ TILs are not correlated with DFS and OS in both univariate and multivariate analyses. Also, we found a significant association between PD-1 positivity and the scores of stromal CD3+ TILs and intraepithelial CD8+ TILs. However, no remarkable relationship was revealed between PD-1 positivity and the survival of HGSOC cases.

Unraveling the Transcriptomic Signatures of Homologous Recombination Deficiency in Ovarian Cancers.

Homologous recombination deficiency (HRD) is a crucial driver of tumorigenesis by inducing impaired repair of double-stranded DNA breaks. Although HRD possibly triggers the production of numerous tumor neoantigens that sufficiently stimulate and activate various tumor-immune responses, a comprehensive understanding of the HRD-associated tumor microenvironment is elusive. To investigate the effect of HRD on the selective enrichment of transcriptomic signatures, 294 cases from The Cancer Genome Atlas-Ovarian Cancer project with both RNA-sequencing and SNP array data are analyzed. Differentially expressed gene analysis and network analysis are performed to identify HRD-specific signatures. Gene-sets associated with mitochondrial activation, including enhanced oxidative phosphorylation (OxPhos), are significantly enriched in the HRD-high group. Furthermore, a wide range of immune cell activation signatures is enriched in HRD-high cases of high-grade serous ovarian cancer (HGSOC). On further cell-type-specific analysis, M1-like macrophage genes are significantly enriched in HRD-high HGSOC cases, whereas M2-macrophage-related genes are not. The immune-response-associated genomic features, including tumor mutation rate, neoantigens, and tumor mutation burdens, correlated with HRD scores. In conclusion, the results of this study highlight the biological properties of HRD, including enhanced energy metabolism, increased tumor neoantigens and tumor mutation burdens, and consequent exacerbation of immune responses, particularly the enrichment of M1-like macrophages in HGSOC cases.

Strong founder effect for BRCA1 c.3629_3630delAG pathogenic variant in Chechen patients with breast or ovarian cancer.

Coding sequences of BRCA1, BRCA2, ATM, TP53, and PALB2 genes were analyzed in 68 consecutive Chechen patients with high-grade serous ovarian cancer (HGSOC). Pathogenic BRCA1/2 variants were identified in 15 (22%) out of 68 HGSOC cases. Nine out of ten patients with BRCA1 pathogenic alleles carried the same deletion (c.3629_3630delAG), and three out of five BRCA2 heterozygotes had Q3299X allele. The analysis of 49 consecutive patients with triple-negative breast cancer (TNBC) revealed 3 (6%) additional BRCA1 heterozygotes. All women with BRCA1 c.3629_3630delAG allele also carried linked c.1067G>A (Q356R) single nucleotide polymorphism, indicating that this is a genuine founder variant but not a mutational hotspot. An ATM truncating allele was detected in one HGSOC patient. There were no women with TP53 or PALB2 germline alterations. Genetic analysis of non-selected HGSOC patients is an efficient tool for the identification of ethnicity-specific BRCA1/2 pathogenic variants.

Novel Diagnostic Biomarkers for High-Grade Serous Ovarian Cancer Uncovered by Data-Independent Acquisition Mass Spectrometry.

High-grade serous ovarian cancer (HGSOC) represents the major histological type of ovarian cancer, and the lack of effective screening tools and early detection methods significantly contributes to the poor prognosis of HGSOC. Currently, there are no reliable diagnostic biomarkers for HGSOC. In this study, we performed liquid chromatography data-independent acquisition tandem mass spectrometry (MS) on depleted serum samples from 26 HGSOC cases and 24 healthy controls (HCs) to discover potential HGSOC diagnostic biomarkers. A total of 1,847 proteins were identified across all samples, among which 116 proteins showed differential expressions between HGSOC patients and HCs. Network modeling showed activations of coagulation and complement cascades, platelet activation and aggregation, neutrophil extracellular trap formation, toll-like receptor 4, insulin-like growth factor, and transforming growth factor β signaling, as well as suppression of lipoprotein assembly and Fc gamma receptor activation in HGSOC. Based on the network model, we prioritized 28 biomarker candidates and validated 18 of them using targeted MS assays in an independent cohort. Predictive modeling showed a sensitivity of 1 and a specificity of 0.91 in the validation cohort. Finally, in vitro functional assays on four potential biomarkers (FGA, VWF, ARHGDIB, and SERPINF2) suggested that they may play an important role in cancer cell proliferation and migration in HGSOC. All raw data were deposited in PRIDE (PXD033169).

Abstract 2306: BLU-222, an investigational, potent, and selective CDK2 inhibitor, demonstrated robust antitumor activity in CCNE1-amplified ovarian cancer models

Abstract Background: Cyclin-dependent kinases (CDK) are a class of enzymes that, along with their regulatory cyclin binding partners, drive cell cycle progression. Cell cycle dysregulation is a hallmark of cancer and targeting its genetic drivers can confer therapeutic benefits. Cyclin E1 (CCNE1) gene alterations are common in patients with ovarian cancer and can be found in ~20% of high-grade serous ovarian cancer cases, which tend to be platinum therapy resistant and therefore represent a high medical need. Cyclin E1 is the canonical binding partner of CDK2, which becomes constitutively active when CCNE1 is amplified and overexpressed. Selectively inhibiting CDK2 is an attractive therapeutic option for CCNE1-amplified tumors and may limit off-target CDK-driven toxicities. Here we report preclinical validation studies leading to the development of an orally available CDK2 inhibitor, BLU-222, for the treatment of ovarian cancer harboring a CCNE1 amplification. Methods: BLU-222 selectivity was measured by enzyme assays, cellular target engagement assays (NanoBRET), and proliferation assays in a panel of ovarian cancer cell lines. In vitro cellular potency was assessed by phospho-Rb levels. In vivo antitumor activity of BLU-222 as a single agent or in combination with carboplatin was measured in an OVCAR-3 cell line-derived xenograft (CDX) tumor model harboring a CCNE1 amplification. Results: BLU-222 demonstrated selectivity, both biochemically and in cells, with low nanomolar potency for CDK2 vs other CDK family members (CDK1, -4, -6, -7, and -9). In a panel of ovarian cancer cell lines, those with CCNE1 amplifications were highly sensitive to BLU-222. Consistent with the in vitro profiling, BLU-222 exhibited significant antitumor activity in the OVCAR-3 CDX model. While administration of single-agent carboplatin led to stasis in vivo, the combination of BLU-222 + carboplatin induced durable tumor regression even after treatment cessation. Conclusions: These data provide a strong rationale for advancing BLU-222 towards clinical development in patients with CCNE1-amplified ovarian cancer. Citation Format: Victoria Brown, Phil Ramsden, Nealia House, Richard Vargas, Jian Guo, Ruduan Wang, Riadh Lobbardi, Maxine Chen, Douglas Wilson, Joseph Kim, Neil Bifulco, Michelle Maynard, Emanuele Perola, Dean Zhang, Steve Wenglowsky, Yoon Jong Choi. BLU-222, an investigational, potent, and selective CDK2 inhibitor, demonstrated robust antitumor activity in CCNE1-amplified ovarian cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2306.

Abstract 1551: miR-625-3p enhances chemosensitivity in ovarian cancer cells through exosomal export of cisplatin and paclitaxel

Abstract Although a majority of women with high-grade serous ovarian cancer (HGSC) achieve a complete response to first-line platinum- and paclitaxel-based chemotherapy, around thirty percent of patients are identified as incomplete responders. Their diseases typically either does not respond or progresses during treatment (refractory) or recurs within 6 months of completing treatment (resistant), suggesting the inherit or intrinsic characteristics of the tumor. Currently, there are no biomarkers that can predict intrinsic resistance, which can avoid unnecessary treatment and toxicity. MicroRNAs (miRNAs) provide a novel master layer of regulation of gene expression. However, the molecular mechanisms by which miRNAs confer a chemoresistant phenotype in ovarian cancer have not been elucidated. To identify miRNAs that are associated with intrinsic chemoresistance in HGSC, Ion Torrent next-generation sequencing analysis of miRNAs was performed on microdissected chemosensitive and chemorefractory primary HGSC cases. Amongst all the miRNAs that were significantly down-regulated in chemorefractory cases, lower miR-625-3p expression was found to be associated with poorer overall and progression-free survivals. Further functional studies showed that overexpression of miR-625-3p significantly decreased cisplatin and paclitaxel resistance in ovarian cancer cells in vitro and in vivo. Online target prediction algorithms together with transcriptome profiling of HGSC cells transfected with miR-625-3p mimics or control mimics identified SSX2IP as a direct target of miR-625-3p, suggesting that SSX2IP may play a role in conferring cisplatin/paclitaxel resistance in HGSC by mediating the effect of miR-625-3p. SSX2IP is a microtubule anchoring and centriolar satellite protein, which plays a critical role in controlling microtubule length and orientation, and centrosome maturation. We demonstrated that HGSC cells transfected with SSX2IP had marked increases in microtubule masses, intracellular multivesicular body trafficking and exosomal cisplatin level; and a decrease in intracellular cisplatin level. In conclusion, down-regulation of miR-625-3p confers cisplatin/paclitaxel resistance in ovarian cancer cells via its novel direct target SSX2IP. SSX2IP alters the microtubule dynamics and subsequently mediates inter-organelle crosstalks between microtubules and multivesicular bodies, which facilitate exosomal export of cisplatin and paclitaxel of HGSC cells. This study is crucial for developing new predictive biomarkers for intrinsic chemoresistance, and new treatment strategies for HGSC based on upregulating miR-625-3p or downregulating SSX2IP expression in ovarian cancer cells, which will enhance cisplatin and paclitaxel sensitivity, and improve patient survival rates. Citation Format: Chi Lam Au Yeung, Tetsushi Tsuruga, Kay-Pong Yip, Sammy Ferri-Borgogno, Samuel Mok. miR-625-3p enhances chemosensitivity in ovarian cancer cells through exosomal export of cisplatin and paclitaxel [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1551.