Genome-wide association analyses of ovarian cancer patients undergoing primary debulking surgery identify candidate genes for residual disease

Survival from ovarian cancer depends on the resection status after primary surgery. We performed genome-wide association analyses for resection status of 7705 ovarian cancer patients, including 4954 with high-grade serous carcinoma (HGSOC), to identify variants associated with residual disease. The most significant association with resection status was observed for rs72845444, upstream of MGMT, in HGSOC (p = 3.9 × 10-8). In gene-based analyses, PPP2R5C was the most strongly associated gene in HGSOC after stage adjustment. In an independent set of 378 ovarian tumours from the AGO-OVAR 11 study, variants near MGMT and PPP2R5C correlated with methylation and transcript levels, and PPP2R5C mRNA levels predicted progression-free survival in patients with residual disease. MGMT encodes a DNA repair enzyme, and PPP2R5C encodes the B56γ subunit of the PP2A tumour suppressor. Our results link heritable variation at these two loci with resection status in HGSOC.

Large-scale genome-wide association study of 398,238 women unveils seven novel loci associated with high-grade serous epithelial ovarian cancer risk

Background

Nineteen genomic regions have been associated with high-grade serous ovarian cancer (HGSOC). We used data from the Ovarian Cancer Association Consortium (OCAC), Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA), UK Biobank (UKBB), and FinnGen to identify novel HGSOC susceptibility loci and develop polygenic scores (PGS).

Methods

We analyzed >22 million variants for 398,238 women. Associations were assessed separately by consortium and meta-analysed. OCAC and CIMBA data were used to develop PGS which were trained on FinnGen data and validated in UKBB and BioBank Japan.

Results

Eight novel variants were associated with HGSOC risk. An interesting discovery biologically was finding that TP53 3'-UTR SNP rs78378222 was associated with HGSOC (per T allele relative risk (RR)=1.44, 95%CI:1.28-1.62, P=1.76×10-9). The optimal PGS included 64,518 variants and was associated with an odds ratio of 1.46 (95%CI:1.37-1.54) per standard deviation in the UKBB validation (AUROC curve=0.61, 95%CI:0.59-0.62).

Conclusions

This study represents the largest GWAS for HGSOC to date. The results highlight that improvements in imputation reference panels and increased sample sizes can identify HGSOC associated variants that previously went undetected, resulting in improved PGS. The use of updated PGS in cancer risk prediction algorithms will then improve personalized risk prediction for HGSOC.

Mapping inherited genetic variation with opposite effects on autoimmune disease and cancer identifies candidate drug targets associated with the anti-tumor immune response

Background

Germline alleles near genes that encode certain immune checkpoints (CTLA4, CD200) are associated with autoimmune/autoinflammatory disease and cancer but in opposite directions. This motivates a systematic search for additional germline alleles which demonstrate this pattern with the aim of identifying potential cancer immunotherapeutic targets using human genetic evidence.

Methods

Pairwise fixed effect cross-disorder meta-analyses combining genome-wide association studies (GWAS) for breast, prostate, ovarian and endometrial cancers (240,540 cases/317,000 controls) and seven autoimmune/autoinflammatory diseases (112,631 cases/895,386 controls) coupled with in silico follow-up. To ensure detection of alleles with opposite effects on cancer and autoimmune/autoinflammatory disease, the signs on the beta coefficients in the autoimmune/autoinflammatory GWAS were reversed prior to meta-analyses.

Results

Meta-analyses followed by linkage disequilibrium clumping identified 312 unique, independent lead variants with Pmeta<5x10-8 associated with at least one of the cancer types at Pcancer<10-3 and one of the autoimmune/autoinflammatory diseases at Pauto<10-3. At each lead variant, the allele that conferred autoimmune/autoinflammatory disease risk was protective for cancer. Mapping each lead variant to its nearest gene as its putative functional target and focusing on genes with established immunological effects implicated 32 of the nearest genes. Tumor bulk RNA-Seq data highlighted that the tumor expression of 5/32 genes (IRF1, IKZF1, SPI1, SH2B3, LAT) were each strongly correlated (Spearman's ρ>0.5) with at least one intra-tumor T/myeloid cell infiltration marker (CD4, CD8A, CD11B, CD45) in every one of the cancer types. Tumor single-cell RNA-Seq data from all cancer types showed that the five genes were more likely to be expressed in intra-tumor immune versus malignant cells. The five lead SNPs corresponding to these genes were linked to them via expression quantitative trait locus mechanisms and at least one additional line of functional evidence. Proteins encoded by the genes were predicted to be druggable.

Conclusion

We provide population-scale germline genetic and functional genomic evidence to support further evaluation of the proteins encoded by IRF1, IKZF1, SPI1, SH2B3, and LAT as possible targets for cancer immunotherapy.

Molecular subtypes of high-grade serous ovarian cancer across racial groups and gene expression platforms

Introduction

High-grade serous carcinoma (HGSC) gene expression subtypes are associated with differential survival. We characterized HGSC gene expression in Black individuals and considered whether gene expression differences by race may contribute to poorer HGSC survival among Black versus non-Hispanic White individuals.

Methods

We included newly generated RNA-Seq data from Black and White individuals, and array-based genotyping data from four existing studies of White and Japanese individuals. We assigned subtypes using K-means clustering. Cluster- and dataset-specific gene expression patterns were summarized by moderated t-scores. We compared cluster-specific gene expression patterns across datasets by calculating the correlation between the summarized vectors of moderated t-scores. Following mapping to The Cancer Genome Atlas (TCGA)-derived HGSC subtypes, we used Cox proportional hazards models to estimate subtype-specific survival by dataset.

Results

Cluster-specific gene expression was similar across gene expression platforms. Comparing the Black study population to the White and Japanese study populations, the immunoreactive subtype was more common (39% versus 23%-28%) and the differentiated subtype less common (7% versus 22%-31%). Patterns of subtype-specific survival were similar between the Black and White populations with RNA-Seq data; compared to mesenchymal cases, the risk of death was similar for proliferative and differentiated cases and suggestively lower for immunoreactive cases (Black population HR=0.79 [0.55, 1.13], White population HR=0.86 [0.62, 1.19]).

Conclusions

A single, platform-agnostic pipeline can be used to assign HGSC gene expression subtypes. While the observed prevalence of HGSC subtypes varied by race, subtype-specific survival was similar.

Menopausal hormone therapy use and risk of ovarian cancer by race: the ovarian cancer in women of African ancestry consortium

BACKGROUND

Most studies examining post-menopausal menopausal hormone therapy (MHT) use and ovarian cancer risk have focused on White women and few have included Black women.

METHODS

We evaluated MHT use and ovarian cancer risk in Black (n = 800 cases, 1783 controls) and White women (n = 2710 cases, 8556 controls), using data from the Ovarian Cancer in Women of African Ancestry consortium. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association of MHT use with ovarian cancer risk, examining histotype, MHT type and duration of use.

RESULTS

Long-term MHT use, ≥10 years, was associated with an increased ovarian cancer risk for White women (OR = 1.38, 95%CI: 1.22-1.57) and the association was consistent for Black women (OR = 1.20, 95%CI: 0.81-1.78, pinteraction = 0.4). For White women, the associations between long-term unopposed estrogen or estrogen plus progesterone use and ovarian cancer risk were similar; the increased risk associated with long-term MHT use was confined to high-grade serous and endometroid tumors. Based on smaller numbers for Black women, the increased ovarian cancer risk associated with long-term MHT use was apparent for unopposed estrogen use and was predominately confined to other epithelial histotypes.

CONCLUSION

The association between long-term MHT use and ovarian cancer risk was consistent for Black and White women.

Concurrent RB1 loss and BRCA-deficiency predicts enhanced immunological response and long-term survival in tubo-ovarian high-grade serous carcinoma

Background

Somatic loss of the tumour suppressor RB1 is a common event in tubo-ovarian high-grade serous carcinoma (HGSC), which frequently co-occurs with alterations in homologous recombination DNA repair genes including BRCA1 and BRCA2 (BRCA). We examined whether tumour expression of RB1 was associated with survival across ovarian cancer histotypes (HGSC, endometrioid (ENOC), clear cell (CCOC), mucinous (MOC), low-grade serous carcinoma (LGSC)), and how co-occurrence of germline BRCA pathogenic variants and RB1 loss influences long-term survival in a large series of HGSC.

Patients and methods

RB1 protein expression patterns were classified by immunohistochemistry in epithelial ovarian carcinomas of 7436 patients from 20 studies participating in the Ovarian Tumor Tissue Analysis consortium and assessed for associations with overall survival (OS), accounting for patient age at diagnosis and FIGO stage. We examined RB1 expression and germline BRCA status in a subset of 1134 HGSC, and related genotype to survival, tumour infiltrating CD8+ lymphocyte counts and transcriptomic subtypes. Using CRISPR-Cas9, we deleted RB1 in HGSC cell lines with and without BRCA1 mutations to model co-loss with treatment response. We also performed genomic analyses on 126 primary HGSC to explore the molecular characteristics of concurrent homologous recombination deficiency and RB1 loss.

Results

RB1 protein loss was most frequent in HGSC (16.4%) and was highly correlated with RB1 mRNA expression. RB1 loss was associated with longer OS in HGSC (hazard ratio [HR] 0.74, 95% confidence interval [CI] 0.66-0.83, P = 6.8 ×10-7), but with poorer prognosis in ENOC (HR 2.17, 95% CI 1.17-4.03, P = 0.0140). Germline BRCA mutations and RB1 loss co-occurred in HGSC (P < 0.0001). Patients with both RB1 loss and germline BRCA mutations had a superior OS (HR 0.38, 95% CI 0.25-0.58, P = 5.2 ×10-6) compared to patients with either alteration alone, and their median OS was three times longer than non-carriers whose tumours retained RB1 expression (9.3 years vs. 3.1 years). Enhanced sensitivity to cisplatin (P < 0.01) and paclitaxel (P < 0.05) was seen in BRCA1 mutated cell lines with RB1 knockout. Among 126 patients with whole-genome and transcriptome sequence data, combined RB1 loss and genomic evidence of homologous recombination deficiency was correlated with transcriptional markers of enhanced interferon response, cell cycle deregulation, and reduced epithelial-mesenchymal transition in primary HGSC. CD8+ lymphocytes were most prevalent in BRCA-deficient HGSC with co-loss of RB1.

Conclusions

Co-occurrence of RB1 loss and BRCA mutation was associated with exceptionally long survival in patients with HGSC, potentially due to better treatment response and immune stimulation.

The tumor multi-omic landscape of endometrial cancers developed on a germline genetic background of adiposity

High body mass index (BMI) is a causal risk factor for endometrial cancer but the tumor molecular mechanisms affected by adiposity and their therapeutic relevance remain poorly understood. Here we characterize the tumor multi-omic landscape of endometrial cancers that have developed on a background of lifelong germline genetic exposure to elevated BMI. We built a polygenic score (PGS) for BMI in women using data on independent, genome-wide significant variants associated with adult BMI in 434,794 women. We performed germline (blood) genotype quality control and imputation on data from 354 endometrial cancer cases from The Cancer Genome Atlas (TCGA). We assigned each case in this TCGA cohort their genetically predicted life-course BMI based on the BMI PGS. Multivariable generalized linear models adjusted for age, stage, microsatellite status and genetic principal components were used to test for associations between the BMI germline PGS and endometrial cancer tumor genome-wide genomic, transcriptomic, proteomic, epigenomic and immune traits in TCGA. High BMI germline PGS was associated with (i) upregulated tumor gene expression in the IL6-JAK-STAT3 pathway (FDR=4.2×10-7); (ii) increased estimated intra-tumor activated mast cell infiltration (FDR=0.008); (iii) increased single base substitution (SBS) mutational signatures 1 (FDR=0.03) and 5 (FDR=0.09) and decreased SBS13 (FDR=0.09), implicating age-related and APOBEC mutagenesis, respectively; and (iv) decreased tumor EGFR protein expression (FDR=0.07). Alterations in IL6-JAK-STAT3 signaling gene and EGFR protein expression were, in turn, significantly associated with both overall survival and progression-free interval. Thus, we integrated germline and somatic data using a novel study design to identify associations between genetically predicted lifelong exposure to higher BMI and potentially actionable endometrial cancer tumor molecular features. These associations inform our understanding of how high BMI may influence the development and progression of this cancer, impacting endometrial tumor biology and clinical outcomes.

Association of inflammation-related exposures and ovarian cancer survival in a multi-site cohort study of Black women

BACKGROUND

An association was observed between an inflammation-related risk score (IRRS) and worse overall survival (OS) among a cohort of mostly White women with invasive epithelial ovarian cancer (EOC). Herein, we evaluated the association between the IRRS and OS among Black women with EOC, a population with higher frequencies of pro-inflammatory exposures and worse survival.

METHODS

The analysis included 592 Black women diagnosed with EOC from the African American Cancer Epidemiology Study (AACES). Cox proportional hazards models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of the IRRS and OS, adjusting for relevant covariates. Additional inflammation-related exposures, including the energy-adjusted Dietary Inflammatory Index (E-DIITM), were evaluated.

RESULTS

A dose-response trend was observed showing higher IRRS was associated with worse OS (per quartile HR: 1.11, 95% CI: 1.01-1.22). Adding the E-DII to the model attenuated the association of IRRS with OS, and increasing E-DII, indicating a more pro-inflammatory diet, was associated with shorter OS (per quartile HR: 1.12, 95% CI: 1.02-1.24). Scoring high on both indices was associated with shorter OS (HR: 1.54, 95% CI: 1.16-2.06).

CONCLUSION

Higher levels of inflammation-related exposures were associated with decreased EOC OS among Black women.

Role of neighborhood context in ovarian cancer survival disparities: current research and future directions

Ovarian cancer is the fifth leading cause of cancer-associated mortality among US women with survival disparities seen across race, ethnicity, and socioeconomic status, even after accounting for histology, stage, treatment, and other clinical factors. Neighborhood context can play an important role in ovarian cancer survival, and, to the extent to which minority racial and ethnic groups and populations of lower socioeconomic status are more likely to be segregated into neighborhoods with lower quality social, built, and physical environment, these contextual factors may be a critical component of ovarian cancer survival disparities. Understanding factors associated with ovarian cancer outcome disparities will allow clinicians to identify patients at risk for worse outcomes and point to measures, such as social support programs or transportation aid, that can help to ameliorate such disparities. However, research on the impact of neighborhood contextual factors in ovarian cancer survival and in disparities in ovarian cancer survival is limited. This commentary focuses on the following neighborhood contextual domains: structural and institutional context, social context, physical context represented by environmental exposures, built environment, rurality, and healthcare access. The research conducted to date is presented and clinical implications and recommendations for future interventions and studies to address disparities in ovarian cancer outcomes are proposed.

Predicted Proteome Association Studies of Breast, Prostate, Ovarian, and Endometrial Cancers Implicate Plasma Protein Regulation in Cancer Susceptibility

BACKGROUND

Predicting protein levels from genotypes for proteome-wide association studies (PWAS) may provide insight into the mechanisms underlying cancer susceptibility.

METHODS

We performed PWAS of breast, endometrial, ovarian, and prostate cancers and their subtypes in several large European-ancestry discovery consortia (effective sample size: 237,483 cases/317,006 controls) and tested the results for replication in an independent European-ancestry GWAS (31,969 cases/410,350 controls). We performed PWAS using the cancer GWAS summary statistics and two sets of plasma protein prediction models, followed by colocalization analysis.

RESULTS

Using Atherosclerosis Risk in Communities (ARIC) models, we identified 93 protein-cancer associations [false discovery rate (FDR) < 0.05]. We then performed a meta-analysis of the discovery and replication PWAS, resulting in 61 significant protein-cancer associations (FDR < 0.05). Ten of 15 protein-cancer pairs that could be tested using Trans-Omics for Precision Medicine (TOPMed) protein prediction models replicated with the same directions of effect in both cancer GWAS (P < 0.05). To further support our results, we applied Bayesian colocalization analysis and found colocalized SNPs for SERPINA3 protein levels and prostate cancer (posterior probability, PP = 0.65) and SNUPN protein levels and breast cancer (PP = 0.62).

CONCLUSIONS

We used PWAS to identify potential biomarkers of hormone-related cancer risk. SNPs in SERPINA3 and SNUPN did not reach genome-wide significance for cancer in the original GWAS, highlighting the power of PWAS for novel locus discovery, with the added advantage of providing directions of protein effect.

IMPACT

PWAS and colocalization are promising methods to identify potential molecular mechanisms underlying complex traits.

Racial Differences in the Association of Endometriosis and Uterine Leiomyomas With the Risk of Ovarian Cancer

OBJECTIVE

To evaluate associations between endometriosis and uterine leiomyomas with ovarian cancer risk by race and the effect of hysterectomy on these associations.

METHODS

We used data from four case-control studies and two case-control studies nested within prospective cohorts in the OCWAA (Ovarian Cancer in Women of African Ancestry) consortium. The study population included 3,124 Black participants and 5,458 White participants, of whom 1,008 Black participants and 2,237 White participants had ovarian cancer. Logistic regression was used to calculate odds ratios (ORs) and 95% CIs for the associations of endometriosis and leiomyomas with ovarian cancer risk, by race, stratified by histotype and hysterectomy.

RESULTS

The prevalences of endometriosis and leiomyomas were 6.4% and 43.2% among Black participants and 7.0% and 21.5% among White participants, respectively. Endometriosis was associated with an increased risk of endometrioid and clear-cell ovarian cancer in both racial groups (eg, OR for endometrioid tumors for Black and White participants 7.06 [95% CI 3.86-12.91] and 2.17 [95% CI 1.36-3.45], respectively, Phetereogeneity =.003). The association between endometriosis and ovarian cancer risk in White participants was stronger in those without hysterectomy, but no difference was observed in Black participants (all Pinteraction ≥.05). Leiomyomas were associated with an elevated risk of ovarian cancer only in those without hysterectomy in both Black (OR 1.34, 95% CI 1.11-1.62) and White (OR 1.22, 95% CI 1.05-1.41) participants (all Pinteraction ≥.05).

CONCLUSIONS

Black and White participants with endometriosis had a higher risk of ovarian cancer, and hysterectomy modified this association among White participants. Leiomyomas were associated with an increased risk of ovarian cancer in both racial groups, with hysterectomy modifying the risk in both groups. Understanding how racial differences in access to care and treatment options (eg, hysterectomy) may help guide future risk reduction strategies.

Lifetime ovulatory years and risk of epithelial ovarian cancer: a multinational pooled analysis

BACKGROUND

The role of ovulation in epithelial ovarian cancer (EOC) is supported by the consistent protective effects of parity and oral contraceptive use. Whether these factors protect through anovulation alone remains unclear. We explored the association between lifetime ovulatory years (LOY) and EOC.

METHODS

LOY was calculated using 12 algorithms. Odds ratios (ORs) and 95% confidence intervals (CIs) estimated the association between LOY or LOY components and EOC among 26 204 control participants and 21 267 case patients from 25 studies. To assess whether LOY components act through ovulation suppression alone, we compared beta coefficients obtained from regression models with expected estimates assuming 1 year of ovulation suppression has the same effect regardless of source.

RESULTS

LOY was associated with increased EOC risk (OR per year increase = 1.014, 95% CI = 1.009 to 1.020 to OR per year increase = 1.044, 95% CI = 1.041 to 1.048). Individual LOY components, except age at menarche, also associated with EOC. The estimated model coefficient for oral contraceptive use and pregnancies were 4.45 times and 12- to 15-fold greater than expected, respectively. LOY was associated with high-grade serous, low-grade serous, endometrioid, and clear cell histotypes (ORs per year increase = 1.054, 1.040, 1.065, and 1.098, respectively) but not mucinous tumors. Estimated coefficients of LOY components were close to expected estimates for high-grade serous but larger than expected for low-grade serous, endometrioid, and clear cell histotypes.

CONCLUSIONS

LOY is positively associated with nonmucinous EOC. Differences between estimated and expected model coefficients for LOY components suggest factors beyond ovulation underlie the associations between LOY components and EOC in general and for non-HGSOC.

p53 and ovarian carcinoma survival: an Ovarian Tumor Tissue Analysis consortium study

Our objective was to test whether p53 expression status is associated with survival for women diagnosed with the most common ovarian carcinoma histotypes (high-grade serous carcinoma [HGSC], endometrioid carcinoma [EC], and clear cell carcinoma [CCC]) using a large multi-institutional cohort from the Ovarian Tumor Tissue Analysis (OTTA) consortium. p53 expression was assessed on 6,678 cases represented on tissue microarrays from 25 participating OTTA study sites using a previously validated immunohistochemical (IHC) assay as a surrogate for the presence and functional effect of TP53 mutations. Three abnormal expression patterns (overexpression, complete absence, and cytoplasmic) and the normal (wild type) pattern were recorded. Survival analyses were performed by histotype. The frequency of abnormal p53 expression was 93.4% (4,630/4,957) in HGSC compared to 11.9% (116/973) in EC and 11.5% (86/748) in CCC. In HGSC, there were no differences in overall survival across the abnormal p53 expression patterns. However, in EC and CCC, abnormal p53 expression was associated with an increased risk of death for women diagnosed with EC in multivariate analysis compared to normal p53 as the reference (hazard ratio [HR] = 2.18, 95% confidence interval [CI] 1.36-3.47, p = 0.0011) and with CCC (HR = 1.57, 95% CI 1.11-2.22, p = 0.012). Abnormal p53 was also associated with shorter overall survival in The International Federation of Gynecology and Obstetrics stage I/II EC and CCC. Our study provides further evidence that functional groups of TP53 mutations assessed by abnormal surrogate p53 IHC patterns are not associated with survival in HGSC. In contrast, we validate that abnormal p53 IHC is a strong independent prognostic marker for EC and demonstrate for the first time an independent prognostic association of abnormal p53 IHC with overall survival in patients with CCC.

CCNE1 and survival of patients with tubo-ovarian high-grade serous carcinoma: An Ovarian Tumor Tissue Analysis consortium study

BACKGROUND

Cyclin E1 (CCNE1) is a potential predictive marker and therapeutic target in tubo-ovarian high-grade serous carcinoma (HGSC). Smaller studies have revealed unfavorable associations for CCNE1 amplification and CCNE1 overexpression with survival, but to date no large-scale, histotype-specific validation has been performed. The hypothesis was that high-level amplification of CCNE1 and CCNE1 overexpression, as well as a combination of the two, are linked to shorter overall survival in HGSC.

METHODS

Within the Ovarian Tumor Tissue Analysis consortium, amplification status and protein level in 3029 HGSC cases and mRNA expression in 2419 samples were investigated.

RESULTS

High-level amplification (>8 copies by chromogenic in situ hybridization) was found in 8.6% of HGSC and overexpression (>60% with at least 5% demonstrating strong intensity by immunohistochemistry) was found in 22.4%. CCNE1 high-level amplification and overexpression both were linked to shorter overall survival in multivariate survival analysis adjusted for age and stage, with hazard stratification by study (hazard ratio [HR], 1.26; 95% CI, 1.08-1.47, p = .034, and HR, 1.18; 95% CI, 1.05-1.32, p = .015, respectively). This was also true for cases with combined high-level amplification/overexpression (HR, 1.26; 95% CI, 1.09-1.47, p = .033). CCNE1 mRNA expression was not associated with overall survival (HR, 1.00 per 1-SD increase; 95% CI, 0.94-1.06; p = .58). CCNE1 high-level amplification is mutually exclusive with the presence of germline BRCA1/2 pathogenic variants and shows an inverse association to RB1 loss.

CONCLUSION

This study provides large-scale validation that CCNE1 high-level amplification is associated with shorter survival, supporting its utility as a prognostic biomarker in HGSC.

Survival of epithelial ovarian cancer in Black women: a society to cell approach in the African American cancer epidemiology study (AACES)

PURPOSE

The causes for the survival disparity among Black women with epithelial ovarian cancer (EOC) are likely multi-factorial. Here we describe the African American Cancer Epidemiology Study (AACES), the largest cohort of Black women with EOC.

METHODS

AACES phase 2 (enrolled 2020 onward) is a multi-site, population-based study focused on overall survival (OS) of EOC. Rapid case ascertainment is used in ongoing patient recruitment in eight U.S. states, both northern and southern. Data collection is composed of a survey, biospecimens, and medical record abstraction. Results characterizing the survival experience of the phase 1 study population (enrolled 2010-2015) are presented.

RESULTS

Thus far, ~ 650 patients with EOC have been enrolled in the AACES. The five-year OS of AACES participants approximates those of Black women in the Surveillance Epidemiology and End Results (SEER) registry who survive at least 10-month past diagnosis and is worse compared to white women in SEER, 49 vs. 60%, respectively. A high proportion of women in AACES have low levels of household income (45% < $25,000 annually), education (51% ≤ high school education), and insurance coverage (32% uninsured or Medicaid). Those followed annually differ from those without follow-up with higher levels of localized disease (28 vs 24%) and higher levels of optimal debulking status (73 vs 67%).

CONCLUSION

AACES is well positioned to evaluate the contribution of social determinants of health to the poor survival of Black women with EOC and advance understanding of the multi-factorial causes of the ovarian cancer survival disparity in Black women.

Association of Frequent Aspirin Use With Ovarian Cancer Risk According to Genetic Susceptibility

Importance

Frequent aspirin use is associated with reduced ovarian cancer risk, but it is unknown whether genetic factors modify this association. Understanding effect modifiers is important given that any use of aspirin for ovarian cancer chemoprevention will likely need to focus on specific higher-risk subgroups.

Objective

To evaluate whether the association between frequent aspirin use and ovarian cancer is modified by a polygenic score (PGS) for nonmucinous ovarian cancer.

Design, Setting, and Participants

We pooled individual-level data from 8 population-based case-control studies from the Ovarian Cancer Association Consortium conducted in the US, UK, and Australia between 1995 and 2009. We included case patients and control participants with both genetic data and data on frequent aspirin use. Case patients with mucinous ovarian cancer were excluded. Data were analyzed between November 1, 2021, and July 31, 2022.

Exposures

Frequent aspirin use, defined as daily or almost daily use for 6 months or longer.

Main Outcomes and Measures

The main outcome was nonmucinous epithelial ovarian cancer. We used logistic regression to estimate odds ratios (ORs) and 95% CIs and likelihood ratio tests to investigate effect modification by the PGS.

Results

There were 4476 case patients with nonmucinous ovarian cancer and 6659 control participants included in this analysis. At study enrollment, the median (IQR) age was 58 (50-66) years for case patients and 57 (49-65) years for control participants. Case patients and control participants self-reported that they were Black (122 [3%] vs 218 [3%]), White (3995 [89%] vs 5851 [88%]), or of other race and ethnicity (348 [8%] vs 580 [9%]; race and ethnicity were unknown for 11 [0%] vs 10 [0%]). There were 575 case patients (13%) and 1030 control participants (15%) who reported frequent aspirin use. The 13% reduction in ovarian cancer risk associated with frequent aspirin use (OR, 0.87 [95% CI, 0.76-0.99]) was not modified by the PGS. Consistent ORs were observed among individuals with a PGS less than (0.85 [0.70-1.02]) and greater than (0.86 [0.74-1.01]) the median. Results were similar by histotype.

Conclusions and Relevance

The findings of this study suggest that genetic susceptibility to ovarian cancer based on currently identified common genetic variants does not appear to modify the protective association between frequent aspirin use and ovarian cancer risk. Future work should continue to explore the role of aspirin use for ovarian cancer prevention among individuals who are at higher risk for ovarian cancer.

Lifestyle and personal factors associated with having macroscopic residual disease after ovarian cancer primary cytoreductive surgery

OBJECTIVE

The presence of macroscopic residual disease after primary cytoreductive surgery (PCS) is an important factor influencing survival for patients with high-grade serous ovarian cancer (HGSC). More research is needed to identify factors associated with having macroscopic residual disease. We analyzed 12 lifestyle and personal exposures known to be related to ovarian cancer risk or inflammation to identify those associated with having residual disease after surgery.

METHODS

This analysis used data on 2054 patients with advanced stage HGSC from the Ovarian Cancer Association Consortium. The exposures were body mass index, breastfeeding, oral contraceptive use, depot-medroxyprogesterone acetate use, endometriosis, first-degree family history of ovarian cancer, incomplete pregnancy, menopausal hormone therapy use, menopausal status, parity, smoking, and tubal ligation. Logistic regression models were fit to assess the association between these exposures and having residual disease following PCS.

RESULTS

Menopausal estrogen-only therapy (ET) use was associated with 33% lower odds of having macroscopic residual disease compared to never use (OR = 0.67, 95%CI 0.46-0.97, p = 0.033). Compared to nulliparous women, parous women who did not breastfeed had 36% lower odds of having residual disease (OR = 0.64, 95%CI 0.43-0.94, p = 0.022), while there was no association among parous women who breastfed (OR = 0.90, 95%CI 0.65-1.25, p = 0.53).

CONCLUSIONS

The association between ET and having no macroscopic residual disease is plausible given a strong underlying biologic hypothesis between this exposure and diagnosis with HGSC. If this or the parity finding is replicated, these factors could be included in risk stratification models to determine whether HGSC patients should receive PCS or neoadjuvant chemotherapy.

Increased FOXJ1 protein expression is associated with improved overall survival in high-grade serous ovarian carcinoma: an Ovarian Tumor Tissue Analysis Consortium Study

BACKGROUND

Recently, we showed a >60% difference in 5-year survival for patients with tubo-ovarian high-grade serous carcinoma (HGSC) when stratified by a 101-gene mRNA expression prognostic signature. Given the varied patient outcomes, this study aimed to translate prognostic mRNA markers into protein expression assays by immunohistochemistry and validate their survival association in HGSC.

METHODS

Two prognostic genes, FOXJ1 and GMNN, were selected based on high-quality antibodies, correlation with protein expression and variation in immunohistochemical scores in a preliminary cohort (n = 134 and n = 80, respectively). Six thousand four hundred and thirty-four (FOXJ1) and 5470 (GMNN) formalin-fixed, paraffin-embedded ovarian neoplasms (4634 and 4185 HGSC, respectively) represented on tissue microarrays from the Ovarian Tumor Tissue Analysis consortium underwent immunohistochemical staining and scoring, then univariate and multivariate survival analysis.

RESULTS

Consistent with mRNA, FOXJ1 protein expression exhibited a linear, increasing association with improved overall survival in HGSC patients. Women with >50% expression had the most favourable outcomes (HR = 0.78, 95% CI 0.67-0.91, p < 0.0001). GMNN protein expression was not significantly associated with overall HSGC patient survival. However, HGSCs with >35% GMNN expression showed a trend for better outcomes, though this was not significant.

CONCLUSION

We provide foundational evidence for the prognostic value of FOXJ1 in HGSC, validating the prior mRNA-based prognostic association by immunohistochemistry.

Modification of the Association Between Frequent Aspirin Use and Ovarian Cancer Risk: A Meta-Analysis Using Individual-Level Data From Two Ovarian Cancer Consortia

PURPOSE

Frequent aspirin use has been associated with reduced ovarian cancer risk, but no study has comprehensively assessed for effect modification. We leveraged harmonized, individual-level data from 17 studies to examine the association between frequent aspirin use and ovarian cancer risk, overall and across subgroups of women with other ovarian cancer risk factors.

METHODS

Nine cohort studies from the Ovarian Cancer Cohort Consortium (n = 2,600 cases) and eight case-control studies from the Ovarian Cancer Association Consortium (n = 5,726 cases) were included. We used Cox regression and logistic regression to assess study-specific associations between frequent aspirin use (≥ 6 days/week) and ovarian cancer risk and combined study-specific estimates using random-effects meta-analysis. We conducted analyses within subgroups defined by individual ovarian cancer risk factors (endometriosis, obesity, family history of breast/ovarian cancer, nulliparity, oral contraceptive use, and tubal ligation) and by number of risk factors (0, 1, and ≥ 2).

RESULTS

Overall, frequent aspirin use was associated with a 13% reduction in ovarian cancer risk (95% CI, 6 to 20), with no significant heterogeneity by study design (P = .48) or histotype (P = .60). Although no association was observed among women with endometriosis, consistent risk reductions were observed among all other subgroups defined by ovarian cancer risk factors (relative risks ranging from 0.79 to 0.93, all P-heterogeneity > .05), including women with ≥ 2 risk factors (relative risk, 0.81; 95% CI, 0.73 to 0.90).

CONCLUSION

This study, the largest to-date on aspirin use and ovarian cancer, provides evidence that frequent aspirin use is associated with lower ovarian cancer risk regardless of the presence of most other ovarian cancer risk factors. Risk reductions were also observed among women with multiple risk factors, providing proof of principle that chemoprevention programs with frequent aspirin use could target higher-risk subgroups.

Gene-Expression Profiling of Mucinous Ovarian Tumors and Comparison with Upper and Lower Gastrointestinal Tumors Identifies Markers Associated with Adverse Outcomes

PURPOSE

Advanced-stage mucinous ovarian carcinoma (MOC) has poor chemotherapy response and prognosis and lacks biomarkers to aid stage I adjuvant treatment. Differentiating primary MOC from gastrointestinal (GI) metastases to the ovary is also challenging due to phenotypic similarities. Clinicopathologic and gene-expression data were analyzed to identify prognostic and diagnostic features.

EXPERIMENTAL DESIGN

Discovery analyses selected 19 genes with prognostic/diagnostic potential. Validation was performed through the Ovarian Tumor Tissue Analysis consortium and GI cancer biobanks comprising 604 patients with MOC (n = 333), mucinous borderline ovarian tumors (MBOT, n = 151), and upper GI (n = 65) and lower GI tumors (n = 55).

RESULTS

Infiltrative pattern of invasion was associated with decreased overall survival (OS) within 2 years from diagnosis, compared with expansile pattern in stage I MOC [hazard ratio (HR), 2.77; 95% confidence interval (CI), 1.04-7.41, P = 0.042]. Increased expression of THBS2 and TAGLN was associated with shorter OS in MOC patients (HR, 1.25; 95% CI, 1.04-1.51, P = 0.016) and (HR, 1.21; 95% CI, 1.01-1.45, P = 0.043), respectively. ERBB2 (HER2) amplification or high mRNA expression was evident in 64 of 243 (26%) of MOCs, but only 8 of 243 (3%) were also infiltrative (4/39, 10%) or stage III/IV (4/31, 13%).

CONCLUSIONS

An infiltrative growth pattern infers poor prognosis within 2 years from diagnosis and may help select stage I patients for adjuvant therapy. High expression of THBS2 and TAGLN in MOC confers an adverse prognosis and is upregulated in the infiltrative subtype, which warrants further investigation. Anti-HER2 therapy should be investigated in a subset of patients. MOC samples clustered with upper GI, yet markers to differentiate these entities remain elusive, suggesting similar underlying biology and shared treatment strategies.

Copy Number Variants Are Ovarian Cancer Risk Alleles at Known and Novel Risk Loci

BACKGROUND

Known risk alleles for epithelial ovarian cancer (EOC) account for approximately 40% of the heritability for EOC. Copy number variants (CNVs) have not been investigated as EOC risk alleles in a large population cohort.

METHODS

Single nucleotide polymorphism array data from 13 071 EOC cases and 17 306 controls of White European ancestry were used to identify CNVs associated with EOC risk using a rare admixture maximum likelihood test for gene burden and a by-probe ratio test. We performed enrichment analysis of CNVs at known EOC risk loci and functional biofeatures in ovarian cancer-related cell types.

RESULTS

We identified statistically significant risk associations with CNVs at known EOC risk genes; BRCA1 (PEOC = 1.60E-21; OREOC = 8.24), RAD51C (Phigh-grade serous ovarian cancer [HGSOC] = 5.5E-4; odds ratio [OR]HGSOC = 5.74 del), and BRCA2 (PHGSOC = 7.0E-4; ORHGSOC = 3.31 deletion). Four suggestive associations (P < .001) were identified for rare CNVs. Risk-associated CNVs were enriched (P < .05) at known EOC risk loci identified by genome-wide association study. Noncoding CNVs were enriched in active promoters and insulators in EOC-related cell types.

CONCLUSIONS

CNVs in BRCA1 have been previously reported in smaller studies, but their observed frequency in this large population-based cohort, along with the CNVs observed at BRCA2 and RAD51C gene loci in EOC cases, suggests that these CNVs are potentially pathogenic and may contribute to the spectrum of disease-causing mutations in these genes. CNVs are likely to occur in a wider set of susceptibility regions, with potential implications for clinical genetic testing and disease prevention.

Racial differences in the association of body mass index and ovarian cancer risk in the OCWAA Consortium

BACKGROUND

Obesity disproportionately affects African American (AA) women and has been shown to increase ovarian cancer risk, with some suggestions that the association may differ by race.

METHODS

We evaluated body mass index (BMI) and invasive epithelial ovarian cancer (EOC) risk in a pooled study of case-control and nested case-control studies including AA and White women. We evaluated both young adult and recent BMI (within the last 5 years). Associations were estimated using multi-level and multinomial logistic regression models.

RESULTS

The sample included 1078 AA cases, 2582 AA controls, 3240 White cases and 9851 White controls. We observed a higher risk for the non-high-grade serous (NHGS) histotypes for AA women with obesity (ORBMI 30+= 1.62, 95% CI: 1.16, 2.26) and White women with obesity (ORBMI 30+= 1.20, 95% CI: 1.02, 2.42) compared to non-obese. Obesity was associated with higher NHGS risk in White women who never used HT (ORBMI 30+= 1.40, 95% CI: 1.08, 1.82). Higher NHGS ovarian cancer risk was observed for AA women who ever used HT (ORBMI 30+= 2.66, 95% CI: 1.15, 6.13), while in White women, there was an inverse association between recent BMI and risk of EOC and HGS in ever-HT users (EOC ORBMI 30+= 0.81, 95% CI: 0.69, 0.95, HGS ORBMI 30+= 0.73, 95% CI: 0.61, 0.88).

CONCLUSION

Obesity contributes to NHGS EOC risk in AA and White women, but risk across racial groups studied differs by HT use and histotype.

Racial disparities in epithelial ovarian cancer survival: An examination of contributing factors in the Ovarian Cancer in Women of African Ancestry consortium

Black women diagnosed with epithelial ovarian cancer have poorer survival compared to white women. Factors that contribute to this disparity, aside from socioeconomic status and guideline-adherent treatment, have not yet been clearly identified. We examined data from the Ovarian Cancer in Women of African Ancestry (OCWAA) consortium which harmonized data on 1074 Black women and 3263 white women with ovarian cancer from seven US studies. We selected potential mediators and confounders by examining associations between each variable with race and survival. We then conducted a sequential mediation analysis using an imputation method to estimate total, direct, and indirect effects of race on ovarian cancer survival. Black women had worse survival than white women (HR = 1.30; 95% CI 1.16-1.47) during study follow-up; 67.9% of Black women and 69.8% of white women died. In our final model, mediators of this disparity include college education, nulliparity, smoking status, body mass index, diabetes, diabetes/race interaction, postmenopausal hormone (PMH) therapy duration, PMH duration/race interaction, PMH duration/age interaction, histotype, and stage. These mediators explained 48.8% (SE = 12.1%) of the overall disparity; histotype/stage and PMH duration accounted for the largest fraction. In summary, nearly half of the disparity in ovarian cancer survival between Black and white women in the OCWAA consortium is explained by education, lifestyle factors, diabetes, PMH use, and tumor characteristics. Our findings suggest that several potentially modifiable factors play a role. Further research to uncover additional mediators, incorporate data on social determinants of health, and identify potential avenues of intervention to reduce this disparity is urgently needed.

Race Differences in the Associations between Menstrual Cycle Characteristics and Epithelial Ovarian Cancer

BACKGROUND

Menstrual cycle characteristics-including age at menarche and cycle length- have been associated with ovarian cancer risk in White women. However, the associations between menstrual cycle characteristics and ovarian cancer risk among Black women have been sparsely studied.

METHODS

Using the Ovarian Cancer in Women of African Ancestry (OCWAA) Consortium that includes 1,024 Black and 2,910 White women diagnosed with epithelial ovarian cancer (EOC) and 2,325 Black and 7,549 White matched controls, we investigated associations between menstrual cycle characteristics (age at menarche, age at menstrual regularity, cycle length, and ever missing three periods) and EOC risk by race and menopausal status. Multivariable logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Black women were more likely to be <11 years at menarche than White women (controls: 9.9% vs. 6.0%). Compared with ≥15 years at menarche, <11 years was associated with increased EOC risk for White (OR = 1.25; 95% CI, 0.99-1.57) but not Black women (OR = 1.10; 95% CI, 0.80-1.55). Among White women only, the association was greater for premenopausal (OR = 2.20; 95% CI, 1.31-3.68) than postmenopausal women (OR = 1.06; 95% CI, 0.82-1.38). Irregular cycle length was inversely associated with risk for White (OR = 0.78; 95% CI, 0.62-0.99) but not Black women (OR = 1.06; 95% CI, 0.68-1.66).

CONCLUSIONS

Earlier age at menarche and cycle irregularity are associated with increased EOC risk for White but not Black women.

IMPACT

Associations between menstrual cycle characteristics and EOC risk were not uniform by race.

Abstract 2541: Immune cell clustering in ovarian cancer tumors and its association with survival

New technologies, such as multiplex immunofluorescence microscopy (mIF), are being developed and used for the assessment and visualization of the tumor immune microenvironment (TIME). These assays produce not only an estimate of the abundance of immune cells in the TIME, but also their spatial locations; however, there are currently few approaches to analyze the spatial context of the TIME. Thus, we have developed a framework for the spatial analysis of the TIME using Ripley’s K, coupled with a permutation-based framework to estimate and measure the departure from complete spatial randomness as a measure of the interactions between immune cells. This approach was applied to mIF data collected on tissue microarrays (TMA) and intratumoral regions of interest (ROIs), defined as &gt;90% tumor cells based on pancytokeratin expression and morphology, selected from whole tissue sections from high-grade serous ovarian carcinoma patients (HGSOC) in the African American Cancer Epidemiology Study (94 subjects on TMAs resulting in 263 tissue cores; 93 subjects with 260 ROIs; 27 subjects included in both TMA and ROIs). Cox proportional hazard models, adjusting for stage and age of diagnosis, were constructed to determine the association of abundance and spatial clustering of tumor-infiltrating lymphocytes (TILs; CD3+), cytotoxic T-cells (CD3+ CD8+), and regulatory T-cells (CD3+ FoxP3+) with overall survival. For all models, the referent group was women with no positive cells for the marker of interest. In the analysis of ROIs, HGSOC patients with high abundance and low spatial clustering of TILs (hazard ratio [HR] = 0.069, 95% confidence interval [CI] = 0.01-0.35) and cytotoxic T-cells (HR and CI not estimable as no deaths observed) had the best survival. This finding of better survival in patients with high abundance and low clustering of TILs and cytotoxic T-cells was replicated in the analysis of TMAs (HR = 0.51, 95% CI = 0.31-0.85 for TILs and HR = 0.11, 95% CI = 0.02-0.53 for cytotoxic T-cells). We also demonstrated the models with both abundance and spatial information was more informative than abundance alone (p &lt; 0.01 for CD3+ and CD3+CD8+ in both ROIs and TMAs). High co-localization of regulatory T-cells and cytotoxic T-cells showed best overall survival on both ROI and TMAs (HR=0.49, 95% CI = 0.28-0.88 and HR = 0.42, 95% CI = 0.25-0.71, respectively). The model with spatial co-occurrence information was significantly better than the model with only abundance (p &lt; 0.05). These findings underscore the prognostic importance of evaluating not only immune cell abundance but also the spatial contexture of the immune cells in the ovarian TIME. The use of our framework for spatial analysis of the TIME and immune cell clustering may be applicable in other cancers and provide a novel approach to identification of biomarkers for predicting patient outcomes.

Citation Format: Alex C. Soupir, Christopher M. Wilson, Joellen M. Schildkraut, Lauren C. Peres, Brooke L. Fridley. Immune cell clustering in ovarian cancer tumors and its association with survival [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 2541.

Abstract 2248: Environmental factors associated with residual disease after ovarian cancer primary cytoreduction surgery

Background: Ovarian cancer is the deadliest gynecologic cancer. Standard treatments for advanced stage high-grade serous ovarian cancer, the most common type, include (1) primary cytoreductive surgery (PCS) followed by adjuvant chemotherapy or (2) neoadjuvant chemotherapy (NACT) with interval debulking surgery. Patients in whom PCS is unlikely to yield optimal cytoreduction to no visible residual disease (R0) or who have medical contraindications to PCS are recommended to undergo NACT. Previous studies on associations between environmental factors and risk of any macroscopic residual disease have yielded inconsistent results. We aimed to (1) comprehensively examine the associations between demographic, lifestyle and reproductive factors and risk of residual disease after PCS; and (2) develop and internally validate a risk prediction model based on these factors.

Methods: We used pooled data on 3,492 women who had PCS following a diagnosis with advanced stage high-grade serous ovarian, fallopian tube or primary peritoneal cancers from the Ovarian Cancer Association Consortium. Fifteen exposures of interest included age at diagnosis, menopausal status, race/ethnicity, education level, first-degree family history of ovarian cancer, endometriosis, smoking, body mass index, parity, incomplete pregnancy, tubal ligation, use of combined oral contraceptives, depot-medroxyprogesterone acetate, estrogen (ET), and combined estrogen-progestin therapy. We fit logistic regression models to examine each exposure-residual disease association in 80% of the data (n=2,794; random selection of participants). We developed a risk prediction model including the factors with p-values ≤0.2. Area under the receiver operating characteristic curve (AUC) was used to assess the model’s discrimination in the remaining 20% of the data (n=698).

Results: Of the 3,492 participants, 2,003 (57%) had residual disease following PCS. Older age at diagnosis was associated with an increased risk of residual disease (OR=1.07 per five years, 95% CI 1.03-1.11). In contrast, a family history of ovarian cancer (OR=0.63, 95% CI 0.42-0.95) or ET use for 5+ years (OR=0.61, 95% CI 0.39-0.96) were associated with achieving R0. These above factors were included in the risk prediction model as were race/ethnicity, personal history of endometriosis, and smoking, whose p-values ≤0.2. The model showed modest performance in the validation set (AUC=0.64).

Conclusions: Younger age at diagnosis, family history of ovarian cancer, and long-term ET use were associated with achieving R0 following PCS. Future studies incorporating genetic and clinical factors to improve the risk prediction for residual disease following PCS are warranted.

Citation Format: Minh Tung Phung, Andrew Berchuck, Ellen L. Goode, Marc T. Goodman, Gillian E. Hanley, Jean Richardson, Bronwyn Grout, Anne Chase, Cindy McKinnon Deurloo, Beth Y. Karlan, Toon Van Gorp, Keitaro Matsuo, Karen McLean, Malcolm C. Pike, Joellen M. Schildkraut, Kathryn L. Terry, Anna DeFazio, Penelope M. Webb, Paul D. P. Pharoah, Susan J. Ramus, Celeste Leigh Pearce. Environmental factors associated with residual disease after ovarian cancer primary cytoreduction surgery [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 2248.

Racial Differences in the Tumor Immune Landscape and Survival of Women with High-Grade Serous Ovarian Carcinoma

BACKGROUND

Tumor-infiltrating lymphocytes (TIL) confer a survival benefit among patients with ovarian cancer; however, little work has been conducted in racially diverse cohorts.

METHODS

The current study investigated racial differences in the tumor immune landscape and survival of age- and stage-matched non-Hispanic Black and non-Hispanic White women with high-grade serous ovarian carcinoma (HGSOC) enrolled in two population-based studies (n = 121 in each racial group). We measured TILs (CD3+), cytotoxic T cells (CD3+CD8+), regulatory T cells (CD3+FoxP3+), myeloid cells (CD11b+), and neutrophils (CD11b+CD15+) via multiplex immunofluorescence. Multivariable Cox proportional hazard regression was used to estimate the association between immune cell abundance and survival overall and by race.

RESULTS

Overall, higher levels of TILs, cytotoxic T cells, myeloid cells, and neutrophils were associated with better survival in the intratumoral and peritumoral region, irrespective of tissue compartment (tumor, stroma). Improved survival was noted for T-regulatory cells in the peritumoral region and in the stroma of the intratumoral region, but no association for intratumoral T-regulatory cells. Despite similar abundance of immune cells across racial groups, associations with survival among non-Hispanic White women were consistent with the overall findings, but among non-Hispanic Black women, most associations were attenuated and not statistically significant.

CONCLUSIONS

Our results add to the existing evidence that a robust immune infiltrate confers a survival advantage among women with HGSOC; however, non-Hispanic Black women may not experience the same survival benefit as non-Hispanic White women with HGSOC.

IMPACT

This study contributes to our understanding of the immunoepidemiology of HGSOC in diverse populations.

Multi-modal immune profiling of mucinous ovarian carcinoma: analysis from the Ovarian Tumor Tissue Analysis/Multidisciplinary Ovarian Cancer Outcomes Group consortia

Mucinous ovarian carcinoma (MOC) is a rare histotype of ovarian cancer. Women with advanced disease (FIGO stage III/IV) have very poor outcomes, with 5-year survival of &lt;20%. Little is known about the anti-tumor immune response in MOC, limiting potential immunotherapeutic options for patients.

Immune data from 3 platforms were analysed. A NanoString mRNA expression panel with 39 immune-related genes (n=60 MOC, n=4198 other ovarian histotypes), a NanoString mRNA plexset with PD-1, PD-L1 (n=241 MOC, n=115 upper and lower gastrointestinal (GI) cancers), and 2 multicolor immunofluorescence (mcIF) panels (n=121 MOC) for CD68, PD-L1, PD-1, CD8 and FOXP3. Data overlapped all platforms for 22 MOC. Immune marker expression by ovarian cancer histotype was measured. Uni- and multivariable Cox Proportional Hazards assessed overall survival (OS) within MOC. Hierarchical clustering looked for subgroups of patients based on co-expression of immune genes.

Compared to more common high-grade serous ovarian cancer (HGSC) and GI cancers, MOC were less immunologically active. High IGHM expression was associated with poorer OS (HR 1.31 (95% CI 1.02–1.69), p=0.033). High tumor densities of FOXP3 and PD-1 positive cells conferred poorer OS in a model with age, stage and site; however, these and PD-L1 and CD68 were associated with grade. The 39 gene NanoString and mcIF datasets revealed 4 clusters, roughly translating to immune cold, moderate and hot (groups 3,4). mcIF analysis revealed a subset with PD-L1 expression in the absence of T-regulatory cell infiltrates.

This study provides novel insights into the MOC immune landscape. Despite relatively low immune activity overall, immunotherapy could be explored for a subset of patients with MOC.

Supported by NSW Ministry of Health and UNSW Sydney, through the NSW Health PhD Scholarship Program 2017-2022; Translational Cancer Research Network top-up scholarship 2021

Reproductive Factors Do Not Influence Survival with Ovarian Cancer

BACKGROUND

Previous studies on the association between reproductive factors and ovarian cancer survival are equivocal, possibly due to small sample sizes.

METHODS

Using data on 11,175 people diagnosed with primary invasive epithelial ovarian, fallopian tube, or primary peritoneal cancer (ovarian cancer) from 16 studies in the Ovarian Cancer Association Consortium (OCAC), we examined the associations between survival and age at menarche, combined oral contraceptive use, parity, breastfeeding, age at last pregnancy, and menopausal status using Cox proportional hazard models. The models were adjusted for age at diagnosis, race/ethnicity, education level, and OCAC study and stratified on stage and histotype.

RESULTS

During the mean follow-up of 6.34 years (SD = 4.80), 6,418 patients passed away (57.4%). There was no evidence of associations between the reproductive factors and survival among patients with ovarian cancer overall or by histotype.

CONCLUSIONS

This study found no association between reproductive factors and survival after an ovarian cancer diagnosis.

IMPACT

Reproductive factors are well-established risk factors for ovarian cancer, but they are not associated with survival after a diagnosis of ovarian cancer.

Polygenic risk modeling for prediction of epithelial ovarian cancer risk

Polygenic risk scores (PRS) for epithelial ovarian cancer (EOC) have the potential to improve risk stratification. Joint estimation of Single Nucleotide Polymorphism (SNP) effects in models could improve predictive performance over standard approaches of PRS construction. Here, we implemented computationally efficient, penalized, logistic regression models (lasso, elastic net, stepwise) to individual level genotype data and a Bayesian framework with continuous shrinkage, "select and shrink for summary statistics" (S4), to summary level data for epithelial non-mucinous ovarian cancer risk prediction. We developed the models in a dataset consisting of 23,564 non-mucinous EOC cases and 40,138 controls participating in the Ovarian Cancer Association Consortium (OCAC) and validated the best models in three populations of different ancestries: prospective data from 198,101 women of European ancestries; 7,669 women of East Asian ancestries; 1,072 women of African ancestries, and in 18,915 BRCA1 and 12,337 BRCA2 pathogenic variant carriers of European ancestries. In the external validation data, the model with the strongest association for non-mucinous EOC risk derived from the OCAC model development data was the S4 model (27,240 SNPs) with odds ratios (OR) of 1.38 (95% CI: 1.28-1.48, AUC: 0.588) per unit standard deviation, in women of European ancestries; 1.14 (95% CI: 1.08-1.19, AUC: 0.538) in women of East Asian ancestries; 1.38 (95% CI: 1.21-1.58, AUC: 0.593) in women of African ancestries; hazard ratios of 1.36 (95% CI: 1.29-1.43, AUC: 0.592) in BRCA1 pathogenic variant carriers and 1.49 (95% CI: 1.35-1.64, AUC: 0.624) in BRCA2 pathogenic variant carriers. Incorporation of the S4 PRS in risk prediction models for ovarian cancer may have clinical utility in ovarian cancer prevention programs.

High Prediagnosis Inflammation-Related Risk Score Associated with Decreased Ovarian Cancer Survival

BACKGROUND

There is suggestive evidence that inflammation is related to ovarian cancer survival. However, more research is needed to identify inflammation-related factors that are associated with ovarian cancer survival and to determine their combined effects.

METHODS

This analysis used pooled data on 8,147 women with invasive epithelial ovarian cancer from the Ovarian Cancer Association Consortium. The prediagnosis inflammation-related exposures of interest included alcohol use; aspirin use; other nonsteroidal anti-inflammatory drug use; body mass index; environmental tobacco smoke exposure; history of pelvic inflammatory disease, polycystic ovarian syndrome, and endometriosis; menopausal hormone therapy use; physical inactivity; smoking status; and talc use. Using Cox proportional hazards models, the relationship between each exposure and survival was assessed in 50% of the data. A weighted inflammation-related risk score (IRRS) was developed, and its association with survival was assessed using Cox proportional hazards models in the remaining 50% of the data.

RESULTS

There was a statistically significant trend of increasing risk of death per quartile of the IRRS [HR = 1.09; 95% confidence interval (CI), 1.03-1.14]. Women in the upper quartile of the IRRS had a 31% higher death rate compared with the lowest quartile (95% CI, 1.11-1.54).

CONCLUSIONS

A higher prediagnosis IRRS was associated with an increased mortality risk after an ovarian cancer diagnosis. Further investigation is warranted to evaluate whether postdiagnosis exposures are also associated with survival.

IMPACT

Given that pre- and postdiagnosis exposures are often correlated and many are modifiable, our study results can ultimately motivate the development of behavioral recommendations to enhance survival among patients with ovarian cancer.

Pleiotropic MLLT10 variation confers risk of meningioma and estrogen-mediated cancers

Background

Risk of tumors of the breast, ovary, and meninges has been associated with hormonal factors and with one another. Genome-wide association studies (GWAS) identified a meningioma risk locus on 10p12 near previous GWAS hits for breast and ovarian cancers, raising the possibility of genetic pleiotropy.

Methods

We performed imputation-based fine-mapping in three case-control datasets of meningioma (927 cases, 790 controls), female breast cancer (28 108 cases, 22 209 controls), and ovarian cancer (25 509 cases, 40 941 controls). Analyses were stratified by sex (meningioma), estrogen receptor (ER) status (breast), and histotype (ovarian), then combined using subset-based meta-analysis in ASSET. Lead variants were assessed for association with additional traits in UK Biobank to identify potential effect-mediators.

Results

Two-sided subset-based meta-analysis identified rs7084454, an expression quantitative trait locus (eQTL) near the MLLT10 promoter, as lead variant (5.7 × 10^-14). The minor allele was associated with increased risk of meningioma in females (odds ratio (OR) = 1.42, 95% Confidence Interval (95%CI):1.20-1.69), but not males (OR = 1.19, 95%CI: 0.91-1.57). It was positively associated with ovarian (OR = 1.09, 95%CI:1.06-1.12) and ER+ breast (OR = 1.05, 95%CI: 1.02-1.08) cancers, and negatively associated with ER- breast cancer (OR = 0.91, 95%CI: 0.86-0.96). It was also associated with several adiposity traits (P < 5.0 × 10^-8), but adjusting for body mass index did not attenuate its association with meningioma. MLLT10 and ESR1 expression were positively correlated in normal meninges (P = .058) and meningioma tumors (P = .0065).

Conclusions

We identify a MLLT10 eQTL positively associated with risk of female meningioma, ER+ breast cancer, ovarian cancer, and obesity, and implicate a potential estrogenic mechanism underlying this pleiotropy.

Psychosocial factors associated with genetic testing status among African American women with ovarian cancer: Results from the African American Cancer Epidemiology Study

Background

Racial disparities in the uptake of cancer genetic services are well documented among African American (AA) women. Understanding the multiple social and psychological factors that can influence the uptake of genetic testing among AA women is needed.

Methods

Data came from 270 AA women diagnosed with ovarian cancer and participating in a population‐based, case‐control study of ovarian cancer who were asked about genetic testing. Logistic regression analyses tested the associations of predisposing, enabling, and need factors with reported genetic testing uptake.

Results

One‐third of the sample (35%) reported having had genetic testing. In the multivariable model, AA women with higher incomes had more than double the odds of being tested than those with the lowest income (odds ratio [OR] for $25,000‐$74,999, 2.04; 95% confidence interval [CI], 1.06‐3.99; OR for ≥$75,000, 2.32; 95% CI, 0.92‐5.94). AA women who reported employment discrimination were significantly less likely to report genetic testing than those who did not report job discrimination (OR, 0.39; 95% CI, 0.14‐0.95). Marital status, Medicaid versus other insurance, prayer frequency, and perceived social support were significantly associated with genetic testing uptake in bivariate analyses but were not significant contributors in multivariable analyses.

Conclusions

Consistent with other studies of AA women, a minority of African American Cancer Epidemiology Study participants had undergone genetic testing. Having a lower income and experiencing job discrimination decreased the likelihood of testing. These results provide foundational evidence supporting the need for interventions to improve the uptake of genetic testing among AA women by reducing cost barriers and providing credible assurances that genetic results will be kept private and not affect social factors such as employability.

African American women with lower incomes who have experienced job discrimination are less likely to undergo testing. These results support the need for interventions to reduce cost barriers and provide credible assurances that genetic results will be kept private and not affect social factors such as employability.

Identification of a Locus Near ULK1 Associated With Progression-Free Survival in Ovarian Cancer

BACKGROUND

Many loci have been found to be associated with risk of epithelial ovarian cancer (EOC). However, although there is considerable variation in progression-free survival (PFS), no loci have been found to be associated with outcome at genome-wide levels of significance.

METHODS

We carried out a genome-wide association study (GWAS) of PFS in 2,352 women with EOC who had undergone cytoreductive surgery and standard carboplatin/paclitaxel chemotherapy.

RESULTS

We found seven SNPs at 12q24.33 associated with PFS (P < 5 × 10-8), the top SNP being rs10794418 (HR = 1.24; 95% CI, 1.15-1.34; P = 1.47 × 10-8). High expression of a nearby gene, ULK1, is associated with shorter PFS in EOC, and with poor prognosis in other cancers. SNP rs10794418 is also associated with expression of ULK1 in ovarian tumors, with the allele associated with shorter PFS being associated with higher expression, and chromatin interactions were detected between the ULK1 promoter and associated SNPs in serous and endometrioid EOC cell lines. ULK1 knockout ovarian cancer cell lines showed significantly increased sensitivity to carboplatin in vitro.

CONCLUSIONS

The locus at 12q24.33 represents one of the first genome-wide significant loci for survival for any cancer. ULK1 is a plausible candidate for the target of this association.

IMPACT

This finding provides insight into genetic markers associated with EOC outcome and potential treatment options.See related commentary by Peres and Monteiro, p. 1604.

Pleiotropy-guided transcriptome imputation from normal and tumor tissues identifies candidate susceptibility genes for breast and ovarian cancer

Familial, sequencing, and genome-wide association studies (GWASs) and genetic correlation analyses have progressively unraveled the shared or pleiotropic germline genetics of breast and ovarian cancer. In this study, we aimed to leverage this shared germline genetics to improve the power of transcriptome-wide association studies (TWASs) to identify candidate breast cancer and ovarian cancer susceptibility genes. We built gene expression prediction models using the PrediXcan method in 681 breast and 295 ovarian tumors from The Cancer Genome Atlas and 211 breast and 99 ovarian normal tissue samples from the Genotype-Tissue Expression project and integrated these with GWAS meta-analysis data from the Breast Cancer Association Consortium (122,977 cases/105,974 controls) and the Ovarian Cancer Association Consortium (22,406 cases/40,941 controls). The integration was achieved through application of a pleiotropy-guided conditional/conjunction false discovery rate (FDR) approach in the setting of a TWASs. This identified 14 candidate breast cancer susceptibility genes spanning 11 genomic regions and 8 candidate ovarian cancer susceptibility genes spanning 5 genomic regions at conjunction FDR < 0.05 that were >1 Mb away from known breast and/or ovarian cancer susceptibility loci. We also identified 38 candidate breast cancer susceptibility genes and 17 candidate ovarian cancer susceptibility genes at conjunction FDR < 0.05 at known breast and/or ovarian susceptibility loci. The 22 genes identified by our cross-cancer analysis represent promising candidates that further elucidate the role of the transcriptome in mediating germline breast and ovarian cancer risk.

Abstract 33: Racial disparities in epithelial ovarian cancer survival: An examination of contributing factors in the Ovarian Cancer in Women of African Ancestry (OCWAA) consortium

Purpose of Study: We used multiple mediation analysis to examine why African-American women have poorer ovarian cancer survival compared to white women.

Methods: We examined data from the OCWAA consortium which harmonized questionnaire-based data on 1,075 African-American women and 3,272 white women with ovarian cancer from seven U.S. studies. We first selected potential mediators and confounders by examining their association with race and survival and then incorporated these variables into a sequential multiple mediation analysis. We used multiple imputation and bootstrapping to fit and pool natural effects models with counterfactual exposures and survival times. In order to distinguish the effect of race through mediators and otherwise, we implemented log-normal accelerated failure time and Cox proportional hazards (PH) models.

Results: In OCWAA, 67.8% (n=729) of African-American women and 69.7% (n=2,282) of white women were deceased. The hazard ratio for African-American compared to white women was 1.29 (95%CI=1.15-1.46). In our final model (Table 1), mediators of this disparity in survival included college education, nulliparity, smoking status, body mass index, diabetes, diabetes/race interaction, postmenopausal hormone (PMH) therapy duration, PMH duration/race interaction, PMH duration/age interaction, histotype, and stage. These mediators explained 46.4% (95%CI=30.9-60.0%) of the overall racial disparity, and histotype/stage and PMH duration accounted for the largest fraction.

Conclusions: In the OCWAA consortium, almost half of the disparity in ovarian cancer survival between African-American and white women is explained by education, lifestyle factors, diabetes, PMH use, and tumor characteristics. A more complete understanding of the remaining difference in racial disparity is needed in order to ultimately improve outcomes and reduce disparities.

Table 1.Sequential multiple mediation of racial differences in ovarian cancer survival in OCWAAStepaMediator(s) AddedIndirect Effect HRbDirect Effect HRcTotal Effect HRd% Mediatede1College graduate1.015 (0.960, 1.073)1.308 (1.265, 1.351)1.327 (1.268, 1.389)4.5 (-16.9, 22.0)2Nulliparity1.018 (0.963, 1.076)1.304 (1.261, 1.347)1.327 (1.268, 1.388)5.8 (-15.6, 22.9)3Smoking1.023 (0.968, 1.082)1.296 (1.254, 1.340)1.326 (1.266, 1.387)7.5 (-13.3, 24.8)4BMI,Diabetes,Diabetes/Race Interaction1.051 (0.995, 1.111)1.263 (1.222, 1.305)1.327 (1.268, 1.389)17.0 (-2.2, 33.2)5PMH Duration,PMH Duration/Race Interaction,PMH Duration/Age Interaction1.086 (1.025, 1.149)1.195 (1.157, 1.235)1.298 (1.238, 1.359)31.0 (11.2, 47.3)6Histotype,Stage1.129 (1.073, 1.189)1.149 (1.114, 1.184)1.297 (1.243, 1.353)46.4 (30.9, 60.0)Abbreviations: OCWAA, Ovarian Cancer in Women of African Ancestry; PMH, Postmenopausal hormone; BMI, body mass index.Bold numbers reflect statistically significant values.aSequential order in which the selected mediators were added to the model. Model also includes variables in all preceding steps.bThe indirect effect is the cumulative indirect effect of the variables selected as mediators in a given step and all preceding steps.cThe direct effect is the remaining direct effect through all other non-mediated pathways.dTotal effect is calculated as log(Indirect Effect HR) + log(Direct Effect HR).ePercent (%) mediated is calculated as log(indirect effect HR)/log(total effect HR).

Citation Format: Kristin A. Guertin, Holly R. Harris, Tareq F. Camacho, Courtney E. Johnson, Anna H. Wu, Patricia G. Moorman, Evan Myers, Traci N. Bethea, Elisa V. Bandera, Charlotte E. Joslin, Heather M. Ochs-Balcom, Lauren C. Peres, Will T. Rosenow, Veronica W. Setiawan, Alicia Beeghly-Fadiel, Lauren F. Dempsey, Lynn Rosenberg, Joellen M. Schildkraut. Racial disparities in epithelial ovarian cancer survival: An examination of contributing factors in the Ovarian Cancer in Women of African Ancestry (OCWAA) consortium [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 33.

Genital Powder Use and Risk of Epithelial Ovarian Cancer in the Ovarian Cancer in Women of African Ancestry Consortium

BACKGROUND

Genital powder use is more common among African-American women; however, studies of genital powder use and ovarian cancer risk have been conducted predominantly in White populations, and histotype-specific analyses among African-American populations are limited.

METHODS

We used data from five studies in the Ovarian Cancer in Women of African Ancestry consortium. Participants included 620 African-American cases, 1,146 African-American controls, 2,800 White cases, and 6,735 White controls who answered questions on genital powder use prior to 2014. The association between genital powder use and ovarian cancer risk by race was estimated using logistic regression.

RESULTS

The prevalence of ever genital powder use for cases was 35.8% among African-American women and 29.5% among White women. Ever use of genital powder was associated with higher odds of ovarian cancer among African-American women [OR = 1.22; 95% confidence interval (CI) = 0.97-1.53] and White women (OR = 1.36; 95% CI = 1.19-1.57). In African-American women, the positive association with risk was more pronounced among high-grade serous tumors (OR = 1.31; 95% CI = 1.01-1.71) than with all other histotypes (OR = 1.05; 95% CI = 0.75-1.47). In White women, a significant association was observed irrespective of histotype (OR = 1.33; 95% CI = 1.12-1.56 and OR = 1.38; 95% CI = 1.15-1.66, respectively).

CONCLUSIONS

While genital powder use was more prevalent among African-American women, the associations between genital powder use and ovarian cancer risk were similar across race and did not materially vary by histotype.

IMPACT

This is one of the largest studies to date to compare the associations between genital powder use and ovarian cancer risk, overall and by histotype, between African-American and White women.

Population-based targeted sequencing of 54 candidate genes identifies PALB2 as a susceptibility gene for high-grade serous ovarian cancer

PURPOSE

The known epithelial ovarian cancer (EOC) susceptibility genes account for less than 50% of the heritable risk of ovarian cancer suggesting that other susceptibility genes exist. The aim of this study was to evaluate the contribution to ovarian cancer susceptibility of rare deleterious germline variants in a set of candidate genes.

METHODS

We sequenced the coding region of 54 candidate genes in 6385 invasive EOC cases and 6115 controls of broad European ancestry. Genes with an increased frequency of putative deleterious variants in cases versus controls were further examined in an independent set of 14 135 EOC cases and 28 655 controls from the Ovarian Cancer Association Consortium and the UK Biobank. For each gene, we estimated the EOC risks and evaluated associations between germline variant status and clinical characteristics.

RESULTS

The ORs associated for high-grade serous ovarian cancer were 3.01 for PALB2 (95% CI 1.59 to 5.68; p=0.00068), 1.99 for POLK (95% CI 1.15 to 3.43; p=0.014) and 4.07 for SLX4 (95% CI 1.34 to 12.4; p=0.013). Deleterious mutations in FBXO10 were associated with a reduced risk of disease (OR 0.27, 95% CI 0.07 to 1.00, p=0.049). However, based on the Bayes false discovery probability, only the association for PALB2 in high-grade serous ovarian cancer is likely to represent a true positive.

CONCLUSIONS

We have found strong evidence that carriers of PALB2 deleterious mutations are at increased risk of high-grade serous ovarian cancer. Whether the magnitude of risk is sufficiently high to warrant the inclusion of PALB2 in cancer gene panels for ovarian cancer risk testing is unclear; much larger sample sizes will be needed to provide sufficiently precise estimates for clinical counselling.

Expanding Our Understanding of Ovarian Cancer Risk: The Role of Incomplete Pregnancies

BACKGROUND

Parity is associated with decreased risk of invasive ovarian cancer; however, the relationship between incomplete pregnancies and invasive ovarian cancer risk is unclear. This relationship was examined using 15 case-control studies from the Ovarian Cancer Association Consortium (OCAC). Histotype-specific associations, which have not been examined previously with large sample sizes, were also evaluated.

METHODS

A pooled analysis of 10 470 invasive epithelial ovarian cancer cases and 16 942 controls was conducted. Odds ratios (ORs) and 95% confidence intervals (CIs) for the association between incomplete pregnancies and invasive epithelial ovarian cancer were estimated using logistic regression. All models were conditioned on OCAC study, race and ethnicity, age, and education level and adjusted for number of complete pregnancies, oral contraceptive use, and history of breastfeeding. The same approach was used for histotype-specific analyses.

RESULTS

Ever having an incomplete pregnancy was associated with a 16% reduction in ovarian cancer risk (OR = 0.84, 95% CI = 0.79 to 0.89). There was a trend of decreasing risk with increasing number of incomplete pregnancies (2-sided Ptrend < .001). An inverse association was observed for all major histotypes; it was strongest for clear cell ovarian cancer.

CONCLUSIONS

Incomplete pregnancies are associated with a reduced risk of invasive epithelial ovarian cancer. Pregnancy, including incomplete pregnancy, was associated with a greater reduction in risk of clear cell ovarian cancer, but the result was broadly consistent across histotypes. Future work should focus on understanding the mechanisms underlying this reduced risk.

Depot-Medroxyprogesterone Acetate Use Is Associated with Decreased Risk of Ovarian Cancer: The Mounting Evidence of a Protective Role of Progestins

BACKGROUND

Combined oral contraceptive use is associated with a decreased risk of invasive epithelial ovarian cancer (ovarian cancer). There is suggestive evidence of an inverse association between progestin-only contraceptive use and ovarian cancer risk, but previous studies have been underpowered.

METHODS

The current study used primary data from 7,977 women with ovarian cancer and 11,820 control women in seven case-control studies from the Ovarian Cancer Association Consortium to evaluate the association between use of depot-medroxyprogesterone acetate (DMPA), an injectable progestin-only contraceptive, and ovarian cancer risk. Logistic models were fit to determine the association between ever use of DMPA and ovarian cancer risk overall and by histotype. A systematic review of the association between DMPA use and ovarian cancer risk was conducted.

RESULTS

Ever use of DMPA was associated with a 35% decreased risk of ovarian cancer overall (OR, 0.65; 95% confidence interval, 0.50-0.85). There was a statistically significant trend of decreasing risk with increasing duration of use (P _trend < 0.001). The systematic review yielded six studies, four of which showed an inverse association and two showed increased risk.

CONCLUSIONS

DMPA use appears to be associated with a decreased risk of ovarian cancer in a duration-dependent manner based on the preponderance of evidence. Further study of the mechanism through which DMPA use is associated with ovarian cancer is warranted.

IMPACT

The results of this study are of particular interest given the rise in popularity of progestin-releasing intrauterine devices that have a substantially lower progestin dose than that in DMPA, but may have a stronger local effect.

First- and second-degree family history of ovarian and breast cancer in relation to risk of invasive ovarian cancer in African American and white women

Family history (FH) of ovarian cancer and breast cancer are well-established risk factors for ovarian cancer, but few studies have examined this association in African American (AA) and white women by histotype. We assessed first- and second-degree FH of ovarian and breast cancer and risk of epithelial ovarian cancer in the Ovarian Cancer in Women of African Ancestry Consortium. Analyses included 1052 AA cases, 2328 AA controls, 2380 white cases and 3982 white controls. Race-specific odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multilevel logistic regression with adjustment for covariates. Analyses were stratified by histotype (high-grade serous vs others). First-degree FH of ovarian cancer was associated with high-grade serous carcinoma in AA (OR = 2.32, 95% CI: 1.50, 3.59) and white women (OR = 2.48, 95% CI: 1.82, 3.38). First-degree FH of breast cancer increased risk irrespective of histotype in AAs, but with high-grade serous carcinoma only in white women. Associations with second-degree FH of ovarian cancer were observed for overall ovarian cancer in white women and with high-grade serous carcinoma in both groups. First-degree FH of ovarian cancer and of breast cancer, and second-degree FH of ovarian cancer is strongly associated with high-grade serous ovarian carcinoma in AA and white women. The association of FH of breast cancer with high-grade serous ovarian carcinoma is similar in white women and AA women, but may differ for other histotypes.

Genetically predicted circulating protein biomarkers and ovarian cancer risk

OBJECTIVE

Most women with epithelial ovarian cancer (EOC) are diagnosed after the disease has metastasized and survival in this group remains poor. Circulating proteins associated with the risk of developing EOC have the potential to serve as biomarkers for early detection and diagnosis. We integrated large-scale genomic and proteomic data to identify novel plasma proteins associated with EOC risk.

METHODS

We used the germline genetic variants most strongly associated (P <1.5 × 10-11) with plasma levels of 1329 proteins in 3301 healthy individuals from the INTERVAL study to predict circulating levels of these proteins in 22,406 EOC cases and 40,941 controls from the Ovarian Cancer Association Consortium (OCAC). Association testing was performed by weighting the beta coefficients and standard errors for EOC risk from the OCAC study by the inverse of the beta coefficients from INTERVAL.

RESULTS

We identified 26 proteins whose genetically predicted circulating levels were associated with EOC risk at false discovery rate < 0.05. The 26 proteins included MFAP2, SEMG2, DLK1, and NTNG1 and a group of 22 proteins whose plasma levels were predicted by variants at chromosome 9q34.2. All 26 protein association signals identified were driven by association with the high-grade serous histotype that comprised 58% of the EOC cases in OCAC. Regional genomic plots confirmed overlap of the genetic association signal underlying both plasma protein level and EOC risk for the 26 proteins. Pathway analysis identified enrichment of seven biological pathways among the 26 proteins (Padjusted <0.05), highlighting roles for Focal Adhesion-PI3K-Akt-mTOR and Notch signaling.

CONCLUSION

The identified proteins further illuminate the etiology of EOC and represent promising new EOC biomarkers for targeted validation by studies involving direct measurement of plasma proteins in EOC patient cohorts.

Abstract PO-180: Genital powder use and risk of epithelial ovarian cancer in the Ovarian Cancer in Women of African Ancestry Consortium

PURPOSE: To date, the epidemiology of epithelial ovarian cancer (EOC) among African-American women has been severely understudied. It remains unclear to what extent variation in the prevalence of EOC risk factors may explain incidence disparities between African-American and white women. Genital powder use is more common among African-American women; however, studies of genital power use and EOC risk have been conducted predominantly in white populations, and histotype specific analyses among African-American populations are limited. The objective of this study was to evaluate the association between genital powder use and EOC risk among African-American and white women, overall and by histotype.

METHODS: We used data from four ovarian cancer case-control studies in the Ovarian Cancer in Women of African Ancestry (OCWAA) consortium: the African American Cancer Epidemiology Study, the Los Angeles County Ovarian Cancer Study, the Cook County Case-Control Study, and the North Carolina Ovarian Cancer Study. Participants included 601 African-American cases, 1,012 African-American controls, 2,225 white cases, and 3,086 white controls who answered questions on genital powder use prior to 2014. The association between genital powder use and EOC risk was estimated using logistic regression. Pooled histotype specific odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using polytomous logistic regression. The population attributable risk (PAR) by race was calculated using the Bruzzi method. RESULTS: The prevalence of reporting ever genital powder use was 66% among African-American women and 44% among white women. African- American women who ever used genital powder were 29% more likely to develop EOC compared to African-American women who reported no use (OR=1.29, 95% CI=0.98-1.71). White women who ever used genital powder were 36% more likely to develop EOC compared to white women reporting no use (OR=1.36, 95% CI=1.12- 1.52). The associations were similar when examined by histotype. Among African- American women, the ORs were 1.29 (95% CI=0.94-1.76) for high grade serous (HGS) and 1.38 (95% CI=0.87-2.19) for non-HGS. For white women, the corresponding ORs were 1.27 (95% CI=1.06-1.52) and 1.21 (95% CI=0.96-1.56), respectively. The PAR for genital powder use was slightly higher, but not statistically significantly different, in African-American women (PAR=10.7, 95% CI=3.7-17.5) compared to white women (PAR=7.8, 95% CI=4.9-10.7). CONCLUSION: While the prevalence of ever genital body powder use was higher among African-American women, the associations between genital powder use and ovarian cancer risk were similar between African-American and white women, and did not materially vary by histotype. Further analyses incorporating additional OCWAA studies and using more refined exposure categories (e.g., frequency and duration of powder use, age at first application) are currently being conducted.

Citation Format: Colette P. Davis, Elisa V. Bandera, Traci N. Bethea, Tareq F. Camacho, Charlotte E. Joslin, Anna H. Wu, Alicia Beeghly-Fadiel, Emily K. Cloyd, Patricia G. Moorman, Evan Myers, Heather M. Ochs-Balcom, Lauren C. Peres, Will L. Rosenow, Veronica W. Setiawan, Lynn Rosenberg, Joellen M Schildkraut, Holly R. Harris. Genital powder use and risk of epithelial ovarian cancer in the Ovarian Cancer in Women of African Ancestry Consortium [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-180.

Racial Differences in Population Attributable Risk for Epithelial Ovarian Cancer in the OCWAA Consortium

BACKGROUND

The causes of racial disparities in epithelial ovarian cancer (EOC) incidence remain unclear. Differences in the prevalence of ovarian cancer risk factors may explain disparities in EOC incidence among African American (AA) and White women.

METHODS

We used data from 4 case-control studies and 3 case-control studies nested within prospective cohorts in the Ovarian Cancer in Women of African Ancestry Consortium to estimate race-specific associations of 10 known or suspected EOC risk factors using logistic regression. Using the Bruzzi method, race-specific population attributable risks (PAR) were estimated for each risk factor individually and collectively, including groupings of exposures (reproductive factors and modifiable factors). All statistical tests were 2-sided.

RESULTS

Among 3244 White EOC cases and 9638 controls and 1052 AA EOC cases and 2410 controls, AA women had a statistically significantly higher PAR (false discovery rate [FDR] P < .001) for first-degree family history of breast cancer (PAR = 10.1%, 95% confidence interval [CI] = 6.5% to 13.7%) compared with White women (PAR = 2.6%, 95% CI = 0.8% to 4.4%). After multiple test correction, AA women had a higher PAR than White women when evaluating all risk factors collectively (PAR = 61.6%, 95% CI = 48.6% to 71.3% vs PAR = 43.0%, 95% CI = 32.8% to 51.4%, respectively; FDR P = .06) and for modifiable exposures, including body mass index, oral contraceptives, aspirin, and body powder (PAR = 36.0%, 95% CI = 21.0% to 48.8% vs PAR = 13.8%, 95% CI = 4.5% to 21.8%, respectively; FDR P = .04).

CONCLUSIONS

Collectively, the selected risk factors accounted for slightly more of the risk among AA than White women, and interventions to reduce EOC incidence that are focused on multiple modifiable risk factors may be slightly more beneficial to AA women than White women at risk for EOC.

Development and Validation of the Gene Expression Predictor of High-grade Serous Ovarian Carcinoma Molecular SubTYPE (PrOTYPE)

PURPOSE

Gene expression-based molecular subtypes of high-grade serous tubo-ovarian cancer (HGSOC), demonstrated across multiple studies, may provide improved stratification for molecularly targeted trials. However, evaluation of clinical utility has been hindered by nonstandardized methods, which are not applicable in a clinical setting. We sought to generate a clinical grade minimal gene set assay for classification of individual tumor specimens into HGSOC subtypes and confirm previously reported subtype-associated features.

EXPERIMENTAL DESIGN

Adopting two independent approaches, we derived and internally validated algorithms for subtype prediction using published gene expression data from 1,650 tumors. We applied resulting models to NanoString data on 3,829 HGSOCs from the Ovarian Tumor Tissue Analysis consortium. We further developed, confirmed, and validated a reduced, minimal gene set predictor, with methods suitable for a single-patient setting.

RESULTS

Gene expression data were used to derive the predictor of high-grade serous ovarian carcinoma molecular subtype (PrOTYPE) assay. We established a de facto standard as a consensus of two parallel approaches. PrOTYPE subtypes are significantly associated with age, stage, residual disease, tumor-infiltrating lymphocytes, and outcome. The locked-down clinical grade PrOTYPE test includes a model with 55 genes that predicted gene expression subtype with >95% accuracy that was maintained in all analytic and biological validations.

CONCLUSIONS

We validated the PrOTYPE assay following the Institute of Medicine guidelines for the development of omics-based tests. This fully defined and locked-down clinical grade assay will enable trial design with molecular subtype stratification and allow for objective assessment of the predictive value of HGSOC molecular subtypes in precision medicine applications.See related commentary by McMullen et al., p. 5271.

Offspring sex and risk of epithelial ovarian cancer: a multinational pooled analysis of 12 case-control studies

While childbearing protects against risk of epithelial ovarian cancer (EOC), few studies have explored the impact on maternal EOC risk of sex of offspring, which may affect the maternal environment during pregnancy. We performed a pooled analysis among parous participants from 12 case-controls studies comprising 6872 EOC patients and 9101 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable logistic regression for case-control associations and polytomous logistic regression for histotype-specific associations, all adjusted for potential confounders. In general, no associations were found between offspring sex and EOC risk. However, compared to bearing only female offspring, bearing one or more male offspring was associated with increased risk of mucinous EOC (OR = 1.45; 95% CI = 1.01-2.07), which appeared to be limited to women reporting menarche before age 13 compared to later menarche (OR = 1.71 vs 0.99; P-interaction = 0.02). Bearing increasing numbers of male offspring was associated with greater risks of mucinous tumors (OR = 1.31, 1.84, 2.31, for 1, 2 and 3 or more male offspring, respectively; trend-p = 0.005). Stratifying by hormonally-associated conditions suggested that compared to bearing all female offspring, bearing a male offspring was associated with lower risk of endometrioid cancer among women with a history of adult acne, hirsutism, or polycystic ovary syndrome (OR = 0.49, 95% CI = 0.28-0.83) but with higher risk among women without any of those conditions (OR = 1.64 95% CI = 1.14-2.34; P-interaction = 0.003). Offspring sex influences the childbearing-EOC risk relationship for specific histotypes and conditions. These findings support the differing etiologic origins of EOC histotypes and highlight the importance of EOC histotype-specific epidemiologic studies. These findings also suggest the need to better understand how pregnancy affects EOC risk.

Prognostic gene expression signature for high-grade serous ovarian cancer

BACKGROUND

Median overall survival (OS) for women with high-grade serous ovarian cancer (HGSOC) is ∼4 years, yet survival varies widely between patients. There are no well-established, gene expression signatures associated with prognosis. The aim of this study was to develop a robust prognostic signature for OS in patients with HGSOC.

PATIENTS AND METHODS

Expression of 513 genes, selected from a meta-analysis of 1455 tumours and other candidates, was measured using NanoString technology from formalin-fixed paraffin-embedded tumour tissue collected from 3769 women with HGSOC from multiple studies. Elastic net regularization for survival analysis was applied to develop a prognostic model for 5-year OS, trained on 2702 tumours from 15 studies and evaluated on an independent set of 1067 tumours from six studies.

RESULTS

Expression levels of 276 genes were associated with OS (false discovery rate < 0.05) in covariate-adjusted single-gene analyses. The top five genes were TAP1, ZFHX4, CXCL9, FBN1 and PTGER3 (P < 0.001). The best performing prognostic signature included 101 genes enriched in pathways with treatment implications. Each gain of one standard deviation in the gene expression score conferred a greater than twofold increase in risk of death [hazard ratio (HR) 2.35, 95% confidence interval (CI) 2.02-2.71; P < 0.001]. Median survival [HR (95% CI)] by gene expression score quintile was 9.5 (8.3 to -), 5.4 (4.6-7.0), 3.8 (3.3-4.6), 3.2 (2.9-3.7) and 2.3 (2.1-2.6) years.

CONCLUSION

The OTTA-SPOT (Ovarian Tumor Tissue Analysis consortium - Stratified Prognosis of Ovarian Tumours) gene expression signature may improve risk stratification in clinical trials by identifying patients who are least likely to achieve 5-year survival. The identified novel genes associated with the outcome may also yield opportunities for the development of targeted therapeutic approaches.

Abstract 1180: Estimating the contribution of epidemiologic risk factors to racial differences in epithelial ovarian cancer incidence

Purpose. Although the incidence of epithelial ovarian cancer is highest among non-Hispanic white women, African-American women have the worst survival of all racial/ethnic groups. We hypothesize that differences in the prevalence of known and suspected ovarian cancer risk factors may explain a portion of the differences in incidence of epithelial ovarian cancer between white and African-American women.

Methods. We used data from seven U.S. studies in the Ovarian Cancer in Women of African Ancestry (OCWAA) consortium, the North Carolina Ovarian Cancer Study (NCOCS), the Los Angeles Ovarian Cancer Study (LACOCS), the African-American Cancer Epidemiology Study (AACES), the Cook County Case-Control Study (CCCCS), the Black Women's Health Study (BWHS), the Women's Health Initiative (WHI), and the Multiethnic Cohort Study (MEC). The association between each known or suspected ovarian cancer risk factor (age, parity, oral contraceptive use, tubal ligation, body mass index (BMI), family history of ovarian and breast cancer, menopausal status, education, hysterectomy, aspirin use, talcum powder applied to genital areas, endometriosis, and age at menarche) was estimated using logistic regression with study site interactions to capture heterogeneity across studies. Using the Bruzzi method, population attributable risks (PAR) were calculated by race for each risk factor individually and collectively for all risk factors.

Results. The comparison of 3,249 white ovarian cancer cases and 9,650 controls to 1,054 African-American cases and 2,410 controls revealed notable differences in the PAR of several risk factors by race. African-American women had a statistically significantly higher PAR for family history of breast cancer and BMI ≥30kg/m2compared to white women (10.0% vs. 2.5% and 8.9% vs. 0.4%, respectively). Although not statistically significant, white women had a higher PAR for oral contraceptive use (duration &lt;5 years) and not having had a tubal ligation than African-American women. When evaluating all risk factors collectively, the overall PAR was 63.9% for African-American women and 48.0% for white women. We also calculated overall PARs excluding WHI due to differences in the inclusion criteria for WHI compared to the other population-based studies in OCWAA: 65.7% for African-American women and 57.8% for white women.

Conclusions. Our findings suggest that the known and suspected ovarian cancer risk factors investigated in this study may be partially responsible for differences in ovarian cancer incidence between white and African-American women. Although important across both racial groups, collectively, the factors studied accounted for slightly more of the ovarian cancer risk among African-American women than white women.

Citation Format: Lauren C. Peres, Tareq F. Camacho, Elisa V. Bandera, Traci N. Bethea, Charlotte E. Joslin, Anna H. Wu, Alicia Beeghly-Fadiel, Emily K. Cloyd, Holly R. Harris, Patricia G. Moorman, Evan Myers, Heather M. Ochs-Balcom, Will L. Rosenow, Veronica W. Setiawan, Lynn Rosenberg, Joellen M. Schildkraut. Estimating the contribution of epidemiologic risk factors to racial differences in epithelial ovarian cancer incidence [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 1180.

Assessment of polygenic architecture and risk prediction based on common variants across fourteen cancers

Genome-wide association studies (GWAS) have led to the identification of hundreds of susceptibility loci across cancers, but the impact of further studies remains uncertain. Here we analyse summary-level data from GWAS of European ancestry across fourteen cancer sites to estimate the number of common susceptibility variants (polygenicity) and underlying effect-size distribution. All cancers show a high degree of polygenicity, involving at a minimum of thousands of loci. We project that sample sizes required to explain 80% of GWAS heritability vary from 60,000 cases for testicular to over 1,000,000 cases for lung cancer. The maximum relative risk achievable for subjects at the 99th risk percentile of underlying polygenic risk scores (PRS), compared to average risk, ranges from 12 for testicular to 2.5 for ovarian cancer. We show that PRS have potential for risk stratification for cancers of breast, colon and prostate, but less so for others because of modest heritability and lower incidence.