Trabert, Britton

Abstract Background: Chronic inflammation is implicated in ovarian carcinogenesis, but how different inflammation-related exposures individually or jointly affect histotype-specific associations remains unclear. Materials and Methods: We pooled data from 16 case-control studies in the Ovarian Cancer Association Consortium to evaluate associations of eight inflammation-related factors (anti-inflammatory: aspirin use, tubal ligation (TL); pro-inflammatory: endometriosis, obesity, lifetime ovulatory cycles (LOC), smoking, pelvic inflammatory disease (PID), polycystic ovary syndrome (PCOS)) with epithelial ovarian cancer (OvC) by histologic subtype. We examined individual associations and clustering of risk factors across histotypes and computed population attributable risk (PAR) for each factor. We assessed additive and multiplicative interactions for exposure combinations. Results: Associations with OvC risk differed by histotype (e.g., high-grade serous: aspirin: OR=0.90; 95%CI 0.82, 0.99; TL: OR=0.80; 95%CI 0.73, 0.88; overall serous: endometriosis: OR=1.17; 95%CI 1.03, 1.31; high LOC: OR=1.42; 95%CI 1.28, 1.58; obesity (low-grade serous): OR=1.50; 95%CI 1.14, 1.98). Clustering analyses showed highly correlated risk profiles in endometrioid and clear cell (r=0.91). High-grade serous and mucinous profiles were moderately correlated with endometrioid and clear cell (r=0.60) tumors. The profile for low-grade serous (r=0.36) tumors was distinct from other histotypes. PAR estimates suggested modifying aspirin use, TL, and LOCs could substantially reduce burdens of endometrioid, clear cell and mucinous tumors. Out of 28 exposure combinations tested in overall OvC and 189 by histotype, we observed 12 interactions. Not using aspirin regularly showed positive additive interactions with obesity and high LOCs, particularly in endometrioid tumors (obesity relative excess risk due to interaction (RERI)=0.74, 95%CI 0.31, 1.18; Pint=0.001 for; LOCs RERI=0.80, 95%CI 0.03, 1.56; Pint=0.04). Not using aspirin regularly also showed a positive additive interaction with endometriosis in clear cell tumors (RERI=1.77, 95%CI 0.03, 3.52; Pint=0.05). Lack of TL showed positive interactions with obesity in endometrioid (RERI=0.86, 95%CI 0.17, 1.53; Pint=0.01) and mucinous (RERI=1.10, 95%CI 0.23, 1.97; Pint=0.01) tumors, while negative additive interactions were observed for smoking and endometriosis in endometrioid tumors (RERI=-1.12, 95%CI -2.19, -0.05; Pint=0.04). A multiplicative interaction was observed between obesity and endometriosis in mucinous tumors (Pint=0.01). Conclusion: The findings suggest ovarian tumorigenesis is strongly shaped by pro- and anti-inflammatory pathways that act largely independently. Further examining these pathways may clarify the origins of histotype heterogeneity and guide prevention strategies. Citation Format: Maxwell Akonde, Britton Trabert, SHELLEY TWOROGER, Allan Jensen, Kathryn L. Terry, Joshua Sampson, Hoda Anton-Culver, David Bowtell, Elisa V. Bandera, Angela Brooks-Wilson, Andrew Berchuck, Daniel William Cramer, Linda S. Cook, Julie M. Cunningham, Jennifer A. Doherty, Ellen L. Goode, Marc T. Goodman, Holly Ruth Harris, Susanne K. Kjaer, Nhu Le, Alice Wen-Ron Lee, Francesmary Modugno, Kirsten B. Moysich, Celeste Pearce, Malcolm C. Pike, Harvey A. Risch, Mary A. Rossing, Joellen M. Schildkrau, Daniel O. Stram, Rebecca Sutphen, David Van Den Berg, Penelope M. Webb, Anna Wu, Argyrios Ziogas, Nicolas A. Wentzensen. Inflammation-related exposures and histotype- specific ovarian cancer risk in the Ovarian Cancer Association Consortium (OCAC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6261.

This cohort study evaluates the reduction in risk of high-grade serous carcinoma among women undergoing opportunistic bilateral salpingectomy in Canada.

Abstract Introduction: The purpose of this study is to evaluate the effectiveness of opportunistic salpingectomy (OS), a procedure that aims to remove only the fallopian tubes of general population risk women, for the prevention of epithelial ovarian cancer. Currently, the method of prevention for individuals at high risk of ovarian cancer involves a bilateral salpingo-oophorectomy (BSO), a procedure that removes both the fallopian tubes and ovaries. However, this procedure is not recommended for individuals of the general population, who make up about 80% of ovarian cancers, due to negative health implications to the cardiovascular and skeletal systems because of surgically induced menopause. The effectiveness of the OS in preventing ovarian cancers and how the procedure impacts the histotype distribution of ovarian cancers remains unknown. Study Methods: This study uses a population-based approach and a case-based approach to determine the effectiveness of OS and its impact on histotype distribution, respectively. For the population-based analysis, we will search through clinical databases to acquire cases of individuals who have had an OS and a tumor. A control population who have their fallopian tubes in-tact will also be acquired. A cox-proportional hazard analysis will be performed to determine the effectiveness of the procedure. Using pathological records, the case-based ascertainment of tumors from individuals who have had an OS will be selected and reviewed for histotype confirmation. Fallopian tubes of these patients will also be reviewed for precursor lesions. This cohort will be compared to a historical histotype distribution of ovarian cancers. Results: For the population-based approach, we have to date, identified less than five serous ovarian cancers in individuals who have had an OS (n=40, 477). A comparator surgery was used as a control and showed 21 cancers. For the case-based approach, we have partnered with 23 collaborating institutions from around the world to identify tumors in individuals who have had an OS. We have identified 26 epithelial ovarian cancers, with the most lethal gynecological histotype, high grade serous carcinoma (HGSC), accounting for 23.1% of the total proportion of epithelial ovarian cancer cases (n=6/26). This is significantly less than the historical histotype distribution of HGSC, which is 69.3% (Fisher’s exact test, p<0.0001). One HGSC case had a precursor lesion called a serous tubal intraepithelial carcinoma (STIC) while reviewing fallopian tubes of this individual. TP53 mutation analysis on one HGSC tumor sample showed a frameshift mutation in TP53 (c229fs) with the tumor and the corresponding STIC staining negative for p53 protein expression by immunohistochemistry. Conclusion: This evidence demonstrates the effectiveness of opportunistic salpingectomy for the prevention of ovarian cancer and shows a histotype distribution shift, with the most lethal gynecological malignancy having a significant reduction in cases following the procedure. Citation Format: Ramlogan Sowamber, Alice J. Mei, Paramdeep Kaur, Julianne McLeod, Emily McKay, Alex Lukey, Jamie Bakkum-Gamez, Natalia Buza, Paul Cohen, Kyle Devins, Rhonda Farrell, Christine Garcia, Blake Gilks, Ellen Goode, Anjelica Hodgson, Brooke Howitt, Pei Hui, Jutta Huvila, Anthony Karnezis, Kianoosh Keyhanian, Mary Kinloch, Martin Köbel, Felix KF. Kommoss, Lawrence Kushi, Janice S. Kwon, Kara Long-Roche, Anais Malpica, Jessica N. McAlpine, Dianne Miller, Esther Oliva, Andrea Palicelli, Aleksandra Paliga, Carlos Parra-Herran, Celeste Leigh Pearce, Sharnel Perera, Jurgen M. Piek, Haiyan Qiu, Joseph Rabban, Robert Rome, Miranda Steenbeek, Rebecca Stone, Aline Talhouk, Kristin M. Tischer, Britton Trabert, Penelope M. Webb, John R. Zalcberg, Gillian E. Hanley, David G. Huntsman. Evaluating the effectiveness of opportunistic salpingectomy (OS) for the prevention of epithelial ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Ovarian Cancer Research; 2025 Sep 19-21; Denver, CO. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl):Abstract nr B045.

Abstract Background: Prior infection with Chlamydia trachomatis, indicated by the presence of circulating antibodies against plasmid encoded glycoprotein 3 (Pgp3), is associated with an increased risk of ovarian cancer. The aberrant expression of p53 can be found in up to 95% of ovarian cancers and is an especially frequent feature among high-grade serous cancers. Prior studies have described mechanisms by which Chlamydia reprogram DNA damage response pathways, including those involving p53. However, tumor level expression of p53 among women with and without prior exposure to chlamydia is poorly described. We evaluated whether the association between prior chlamydial infection (Pgp3 seropositivity) and ovarian cancer varied by tumor p53 expression and whether Pgp3 seropositivity was associated with ovarian tumor expression of p53. Methods: Available serologic data for Pgp3 in tubo-ovarian cancer cases (n=155) and matched controls (n=556) from the Polish Ovarian Cancer Study were evaluated and stratified by p53 mutation status of cases inferred from immunohistochemical staining. Expression of p53 was assessed in tissue microarrays (2+ cores per case) and classified as aberrant (i.e., no expression or overexpression: ≥60% positive cells) or wild- type. Multinomial logistic regression with controls as the reference was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association of Pgp3 seropositivity with ovarian cancer with stratification by p53 expression among the cases. Logistic regression among cases was only used to evaluate the association between Pgp3 and aberrant p53 expression. Results: Aberrant p53 expression was found in 70% of cases. Pgp3 seropositivity was associated with increased ovarian cancer risk (OR [95% CI]: 1.86 [1.28-2.68]). Pgp3 seropositivity was associated with risk for both p53 aberrant (1.79 [1.16-2.75]) or p53 wild-type ovarian cancers (2.06 [1.11-3.80], p for heterogeneity=0.80). When restricted to high-grade serous cancers, the association with Pgp3 was also not differential by p53 status (p for heterogeneity=0.16; 83% of high-grade serous cases had aberrant p53 expression). Among women with cancer, Pgp3 seropositivity was not associated with aberrant p53 expression (versus wild-type, OR [95% CI]: 0.90 [0.45-1.81], spearman correlation: -0.05, p-value=0.55). Conclusion/Discussion: Our study provides support that previous C. trachomatis infection is associated with ovarian cancer, irrespective of aberrant p53 tumor expression. There are many possible mechanisms by which Chlamydia may influence ovarian cancer. While the current results do not rule out interactions with p53-related pathways, it is likely that C. trachomatis increases ovarian cancer risk via multiple mechanisms (e.g., infection related sequelae like chronic inflammation). Citation Format: Sarina Pollat, Nicolas Wentzensen, Tim Waterboer, Manila Hada, Jolanta Lissowska, Beata Peplonska, Mark E. Sherman, Kara A. Michels, Britton Trabert. Prior chlamydial infection and ovarian cancer risk by tumor p53 expression [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A051.

Abstract Introduction: There is growing evidence to support a modest inverse association between daily aspirin use and ovarian cancer risk. We previously hypothesized that this association may differ by immune cell infiltration. In our prior study evaluating heterogeneity by tumor-associated macrophage (TAM) infiltration, aspirin use was associated with lower risk of ovarian cancer with high protumorigenic M2-type TAM infiltration, but not low M2-type TAM infiltration. The goal of the present study was to evaluate the hypothesis that the association between aspirin use and ovarian cancer risk also differs by infiltration with tumor-infiltrating lymphocytes (TILs). Methods: We included cases and matched controls from the Nurses’ Health Study (NHS), NHSII, and New England Case Control Study. Study participants self-reported aspirin use including regular use (≥1 x per week), duration of use, and number of tablets. A gynecologic pathologist (JLH), who was blinded to exposure status, reviewed hematoxylin and eosin stained tumor slides to quantify TILs for all cases (n=547). We used polytomous logistic regression, adjusted for ovarian cancer risk factors, to estimate odds ratios (OR) for aspirin use and ovarian cancer risk by TIL infiltration. Results: Overall, recent aspirin use was associated with lower risk of ovarian cancer compared with no regular aspirin use (OR=0.65, 95%CI=0.47-0.89). Recent aspirin use was associated with a lower risk of ovarian cancer exhibiting TIL infiltration (OR=0.38, 95%CI=0.26-0.56) but not with TIL-negative cancers (OR=1.00, 95%CI=0.71-1.41; p-heterogeneity <0.001). We observed similar results for aspirin duration and tablets. For duration, comparing ≥10 years of aspirin use to <1 year we observed a significantly lower risk of ovarian cancer with TILs (OR=0.47, 95%CI=0.41-0.71; p-trend=0.004), but a nonsignificant reduction for ovarian cancer without TILs (OR=0.86, 95%CI=0.59-1.26; p-trend=0.72; p-heterogeneity=0.03). Comparing ≥6 tablets to <1 tablet per week, there was evidence of a lower risk of ovarian cancer with TILs (OR=0.47, 95%CI=0.30-0.75; p-trend=0.001) but not without TILs (OR=1.02, 95%CI=0.70-1.48; p-trend=0.84; p-heterogeneity=0.003). Conclusions: Our results suggest that prediagnosis aspirin use may be an important modulator of immune cell infiltration in ovarian tumors, supporting an immunogenic mechanism for aspirin in ovarian carcinogenesis. Further work is under way to evaluate nonaspirin nonsteroidal anti-inflammatory drugs, and to consider which subsets of TAMs and TILs may be driving heterogeneity in the associations between anti-inflammatory drugs and ovarian cancer risk. Citation Format: Mollie E. Barnard, Britton Trabert, Jonathan L. Hecht, Ellen L. Goode, Naoko Sasamoto, Kathryn L. Terry, Shelley S. Tworoger. Aspirin use and ovarian cancer risk by lymphocyte infiltration [abstract]. In: Proceedings of the AACR Special Conference on Modernizing Population Sciences in the Digital Age; 2019 Feb 19-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(9 Suppl):Abstract nr A19.

Abstract 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.

Abstract Introduction Elevated mammographic density (MD) is a strong and independent risk factor for breast cancer, though underlying mechanisms are unclear. Prior studies have suggested that increased cumulative exposure to sex-steroid hormones and growth factors may impact both MD and MD-related breast cancer risk; however, most studies have only evaluated individual hormones. In this study, we simultaneously explored the relationship between 29 circulating hormones and growth factors with MD among postmenopausal women undergoing diagnostic breast biopsy. Methods We used data from 89 postmenopausal women, aged 44-65, who had complete measurements of 29 serum hormones from a single pre-biopsy blood draw (i.e., sex-steroid hormones: 15 estrogen/estrogen metabolites, 7 progesterone/progesterone metabolites; and non-sex hormones: insulin-like growth factor I and binding proteins (IGFBPs) 2-7). Volumetric MD (% fibroglandular volume) was assessed in pre-biopsy digital mammograms using single X-ray absorptiometry. Sufficient dimension reduction methods were used to compute a composite marker score that accommodates correlations among hormones and their relationship to MD. Backward elimination was applied to select log-transformed hormones contributing to the score at α=0.05; multivariable linear regression was used to further examine associations between selected hormones and MD within a single model, adjusting for age and BMI. Results Pearson correlations between hormones were moderate-to-strong. Dimension reduction methods identified 6 hormones as associated with MD (p<0.05): estradiol, 2-hydroxyestradiol, 2-methoxyestrone, 16-ketoestradiol, IGFBP-2, and 17α-hydroxyprogesterone, in models that considered MD as either continuous or dichotomous (>median vs. ≤median); BMI was consistently identified as the most significant predictor of MD (P <0.0001). In a multivariable linear regression model that included these 6 hormones, in addition to age and BMI, higher levels of 2-methoxyestrone, IGFBP-2, and 17α-hydroxyprogesterone were significantly associated with increased MD, whereas higher levels of age and BMI were significantly associated with lower MD. Conclusions We identified 6 out of 29 correlated hormones that were significantly associated with MD among postmenopausal women. For several, the directions of their associations with MD were comparable to those observed in prior studies that have separately evaluated these hormones in relation to breast cancer risk. We plan to further explore how circulating hormones concurrently affect MD in premenopausal women, accounting for menstrual cycle phase. Incorporation of dimension reduction methods in studies of multiple correlated hormones can help uncover new etiologic insights into the role of hormones and growth factors in MD and breast carcinogenesis and inform strategies for prevention. Citation Format: Shaoqi Fan, Ruth M. Pfeiffer, Manila Hada, Roni T. Falk, Maeve Mullooly, Hannah Oh, Berta Geller, Pamela Vacek, Donald Weave, John Shepherd, Jeff Wang, Sally Herschorn, Louise A. Brinton, Xia Xu, Mark E. Sherman, Britton Trabert, Gretchen L. Gierach. Associations of circulating hormones with mammographic density in postmenopausal women referred to diagnostic breast biopsy [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 3488.

Abstract 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

The association of progesterone/progesterone metabolites with elevated mammographic breast density (MBD) and delayed age-related terminal duct lobular unit (TDLU) involution, strong breast cancer risk factors, has received limited attention. Using a reliable liquid chromatography-tandem mass-spectrometry assay, we quantified serum progesterone/progesterone metabolites and explored cross-sectional relationships with MBD and TDLU involution among women, ages 40–65, undergoing diagnostic breast biopsy. Quantitative MBD measures were estimated in pre-biopsy digital mammograms. TDLU involution was quantified in diagnostic biopsies. Adjusted partial correlations and trends across MBD/TDLU categories were calculated. Pregnenolone was positively associated with percent MBD-area (MBD-A, rho: 0.30; p-trend = 0.01) among premenopausal luteal phase women. Progesterone tended to be positively associated with percent MBD-A among luteal phase (rho: 0.26; p-trend = 0.07) and postmenopausal (rho: 0.17; p-trend = 0.04) women. Consistent with experimental data, implicating an elevated 5α-pregnanes/3α-dihydroprogesterone (5αP/3αHP) metabolite ratio in breast cancer, higher 5αP/3αHP was associated with elevated percent MBD-A among luteal phase (rho: 0.29; p-trend = 0.08), but not postmenopausal women. This exploratory analysis provided some evidence that endogenous progesterone and progesterone metabolites might be correlated with MBD, a strong breast cancer risk factor, in both pre- and postmenopausal women undergoing breast biopsy. Additional studies are needed to understand the role of progesterone/progesterone metabolites in breast tissue composition and breast cancer risk.

AbstractSynthetic progestogens (progestins) have been linked to increased breast cancer risk; however, the role of endogenous progesterone in breast physiology and carcinogenesis is less clearly defined. Mechanistic studies using cell culture, tissue culture, and preclinical models implicate progesterone in breast carcinogenesis. In contrast, limited epidemiologic data generally do not show an association of circulating progesterone levels with risk, and it is unclear whether this reflects methodologic limitations or a truly null relationship. Challenges related to defining the role of progesterone in breast physiology and neoplasia include: complex interactions with estrogens and other hormones (eg, androgens, prolactin, etc.), accounting for timing of blood collections for hormone measurements among cycling women, and limitations of assays to measure progesterone metabolites in blood and progesterone receptor isotypes (PRs) in tissues. Separating the individual effects of estrogens and progesterone is further complicated by the partial dependence of PR transcription on estrogen receptor (ER)α-mediated transcriptional events; indeed, interpreting the integrated interaction of the hormones may be more essential than isolating independent effects. Further, many of the actions of both estrogens and progesterone, particularly in “normal” breast tissues, are driven by paracrine mechanisms in which ligand binding to receptor-positive cells evokes secretion of factors that influence cell division of neighboring receptor-negative cells. Accordingly, blood and tissue levels may differ, and the latter are challenging to measure. Given conflicting data related to the potential role of progesterone in breast cancer etiology and interest in blocking progesterone action to prevent or treat breast cancer, we provide a review of the evidence that links progesterone to breast cancer risk and suggest future directions for filling current gaps in our knowledge.