Citations

Abstract DNA methylation is instrumental for gene regulation. Global changes in the epigenetic landscape have been recognized as a hallmark of cancer. However, the role of DNA methylation in epithelial ovarian cancer (EOC) remains unclear. In this study, high-density genetic and DNA methylation data in white blood cells from the Framingham Heart Study (N = 1,595) were used to build genetic models to predict DNA methylation levels. These prediction models were then applied to the summary statistics of a genome-wide association study (GWAS) of ovarian cancer including 22,406 EOC cases and 40,941 controls to investigate genetically predicted DNA methylation levels in association with EOC risk. Among 62,938 CpG sites investigated, genetically predicted methylation levels at 89 CpG were significantly associated with EOC risk at a Bonferroni-corrected threshold of P < 7.94 × 10−7. Of them, 87 were located at GWAS-identified EOC susceptibility regions and two resided in a genomic region not previously reported to be associated with EOC risk. Integrative analyses of genetic, methylation, and gene expression data identified consistent directions of associations across 12 CpG, five genes, and EOC risk, suggesting that methylation at these 12 CpG may influence EOC risk by regulating expression of these five genes, namely MAPT, HOXB3, ABHD8, ARHGAP27, and SKAP1. We identified novel DNA methylation markers associated with EOC risk and propose that methylation at multiple CpG may affect EOC risk via regulation of gene expression. Significance: Identification of novel DNA methylation markers associated with EOC risk suggests that methylation at multiple CpG may affect EOC risk through regulation of gene expression.

Thymidylate synthase (TYMS) is a crucial enzyme for DNA synthesis. TYMS expression is regulated by its antisense mRNA, ENOSF1. Disrupted regulation may promote uncontrolled DNA synthesis and tumor growth. We sought to replicate our previously reported association between rs495139 in the TYMS-ENOSF1 3′ gene region and increased risk of mucinous ovarian carcinoma (MOC) in an independent sample. Genotypes from 24,351 controls to 15,000 women with invasive OC, including 665 MOC, were available. We estimated per-allele odds ratios (OR) and 95% confidence intervals (CI) using unconditional logistic regression, and meta-analysis when combining these data with our previous report. The association between rs495139 and MOC was not significant in the independent sample (OR = 1.09; 95% CI = 0.97–1.22; p = 0.15; N = 665 cases). Meta-analysis suggested a weak association (OR = 1.13; 95% CI = 1.03–1.24; p = 0.01; N = 1019 cases). No significant association with risk of other OC histologic types was observed (p = 0.05 for tumor heterogeneity). In expression quantitative trait locus (eQTL) analysis, the rs495139 allele was positively associated with ENOSF1 mRNA expression in normal tissues of the gastrointestinal system, particularly esophageal mucosa (r = 0.51, p = 1.7 × 10−28), and nonsignificantly in five MOC tumors. The association results, along with inconclusive tumor eQTL findings, suggest that a true effect of rs495139 might be small.

Abstract Background: Pelvic inflammatory disease (PID) has been associated with ovarian cancer and Chlamydia trachomatis (chlamydia) is the leading cause of PID in the developed world. Primary infection with chlamydia is often asymptomatic and may persist for several months/years, thus ascertainment of PID in epidemiologic studies is challenging due to pervasive misclassification and under-reporting. To improve our understanding of the role of chlamydia and other infectious agents in developing ovarian cancer, we evaluated serologic markers of infection with incident ovarian cancer using a staged approach in two independent populations. Methods: Studies included: 1) a case-control study conducted in Poland of 278 ovarian cancer cases diagnosed from 2000 to 2003 and age- and study site-matched controls (n=556) and 2) a nested case-control study from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial including 160 women who eventually developed ovarian cancer and 159 matched controls. We calculated odds ratios (OR) and 95% confidence intervals (CI) for the association between serologic marker titers and ovarian cancer risk using logistic regression adjusted for matching factors and potential confounders. We evaluated laboratory cutpoints indicative of prior chlamydia infection and tested more stringent marker thresholds, identified in Poland and applied in PLCO, that could be relevant for a PID-like infection. Results: In the Polish study, positivity for the chlamydia plasmid-encoded Pgp3 protein was associated with increased ovarian cancer risk [OR (95% CI): 1.63 (1.20-2.22)]; when a positive result was redefined at a higher titer, ovarian cancer risk increased [cutpoint 2: 2.00 (1.38-2.89); cutpoint 3 (max OR): 2.19 (1.29-3.73)]. All other chlamydia markers measured were associated with increased risk at the more stringent positivity threshold in Poland. In the prospective PLCO study, Pgp3 was associated with elevated risk at the laboratory cutpoint [1.43 (0.78-2.63)]; using higher thresholds, Pgp3 was associated with increased ovarian cancer risk [cutpoint 2: 2.25 (1.07-4.71); cutpoint 3: 2.53 (0.63-10.08)]. In both studies, markers of other infections (i.e., Mycoplasma genitalium, herpes simplex virus-2, human papillomavirus, herpes simplex virus-1, polyomavirus, hepatitis B, hepatitis C, Epstein Barr virus, cytomegalovirus) measured were not associated with risk. Conclusions: In two independent populations, the gold standard serologic marker of prior/current chlamydia infection (Pgp3) was associated with a doubling in ovarian cancer risk, whereas markers of other infectious agents were unrelated. Although these findings need to be replicated, they suggest potential ovarian cancer risk reduction through targeted treatment of chlamydia infections. Citation Format: Britton Trabert, Tim Waterboer, Sally B. Coburn, Louise A. Brinton, Mark E. Sherman, Jolanta Lissowska, Beata Peplonska, Patricia Hartge, Michael Pawlita, Nicolas Wentzensen. Serologic markers of infectious agents and ovarian cancer: Markers of prior Chlamydia trachomatis infection associated with increased ovarian cancer risk in two independent populations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4942.

Abstract Background: Endometrial cancer (EC) is the most common gynecologic malignancy in developed countries and the incidence and mortality of EC continue to rise in the US. When detected early, EC is highly curable, suggesting that early detection strategies could reduce EC mortality. Women who develop EC often have a prolonged history of abnormal bleeding, offering a window for identifying many at-risk women prior to the development of advanced cancer. To evaluate risk prediction, novel sampling and early detection strategies in women at increased risk of EC, we established a prospective cohort of women with abnormal bleeding that is followed for endometrial hyperplasia and cancer endpoints. Methods: We consecutively enrolled women ≥45 years old presenting to the Mayo Clinic for evaluation of abnormal uterine bleeding (AUB), postmenopausal bleeding (PMB), thickened endometrial stripe (ES) on imaging, or Lynch Syndrome (LS). From all women, an intravaginal tampon and an endometrial brushing via Tao brush were collected before endometrial biopsy. Epidemiological EC risk factor data, clinical data, and endometrial biopsy histology results were abstracted from medical records. Absolute risk of endometrial hyperplasia and EC were calculated overall and in strata based on clinical symptoms and risk factors. Results: Among the first 1,000 women enrolled into the study, 712 (71%) were overweight or obese, 534 (53%) were postmenopausal, and 214 (22%) were current hormone replacement therapy (HRT) users. Endometrial biopsy and, if indicated, subsequent hysterectomy, detected 39 ECs, 16 atypical hyperplasias, and 28 hyperplasias without atypia at baseline evaluation. Among 534 postmenopausal women, 453 (85%) reported any type of bleeding, with spotting (39%) and light bleeding (27%) being more common than heavy bleeding (14%). Among perimenopausal women with AUB (n=452), the absolute risk of EC at baseline was 0.9% and among women with PMB, the absolute risk of EC at baseline was 7.5%. Among women with PMB, EC risk was modified by HRT use (risk of 2.6% in women on HRT and 8.2% in women not on HRT, respectively), obesity (risk of 5.3%, 8.1% and 9.5% for women with normal, overweight, and obese BMI, respectively), and type of bleeding (risk of 9.7%, 4.9%, and 8.2% in women with spotting, light or heavy bleeding, respectively). Discussion: While risk of endometrial cancer in perimenopausal women with AUB is low, approximately 8% of women presenting for clinical work up of PMB have underlying EC. Clinical presentation and risk factors modify the absolute risk of EC and may inform clinical management. Additional recruitment and prospective follow-up is underway to improve estimates of short- and long-term EC risk in women with PMB. With its collection of tampon and Tao brush samples, the study will provide a unique resource to evaluate molecular markers of EC and EC risk in elevated-risk women. Citation Format: Nicolas A. Wentzensen, Megan Clarke, Viji Shridhar, Maureen Lemens, Matthew Hopkins, Lisa Ahlberg, Shannon Laughlin-Tommaso, Karl Podratz, Mark Sherman, Jamie Bakkum-Gamez. A prospective study of endometrial cancer detection in women presenting for evaluation of abnormal peri- and postmenopausal bleeding [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2203.

Abstract Large-scale genome-wide association studies (GWAS) have identified approximately 35 loci associated with epithelial ovarian cancer (EOC) risk. The majority of GWAS-identified disease susceptibility variants are located in noncoding regions, and causal genes underlying these associations remain largely unknown. Here, we performed a transcriptome-wide association study to search for novel genetic loci and plausible causal genes at known GWAS loci. We used RNA sequencing data (68 normal ovarian tissue samples from 68 individuals and 6,124 cross-tissue samples from 369 individuals) and high-density genotyping data from European descendants of the Genotype-Tissue Expression (GTEx V6) project to build ovarian and cross-tissue models of genetically regulated expression using elastic net methods. We evaluated 17,121 genes for their cis-predicted gene expression in relation to EOC risk using summary statistics data from GWAS of 97,898 women, including 29,396 EOC cases. With a Bonferroni-corrected significance level of P < 2.2 × 10−6, we identified 35 genes, including FZD4 at 11q14.2 (Z = 5.08, P = 3.83 × 10−7, the cross-tissue model; 1 Mb away from any GWAS-identified EOC risk variant), a potential novel locus for EOC risk. All other 34 significantly associated genes were located within 1 Mb of known GWAS-identified loci, including 23 genes at 6 loci not previously linked to EOC risk. Upon conditioning on nearby known EOC GWAS-identified variants, the associations for 31 genes disappeared and three genes remained (P < 1.47 × 10−3). These data identify one novel locus (FZD4) and 34 genes at 13 known EOC risk loci associated with EOC risk, providing new insights into EOC carcinogenesis. Significance: Transcriptomic analysis of a large cohort confirms earlier GWAS loci and reveals FZD4 as a novel locus associated with EOC risk. Cancer Res; 78(18); 5419–30. ©2018 AACR.

Abstract Background: Endometrial cancer is highly curable when detected early, but clinical symptoms are often missed. Most cancers arise in women with abnormal postmenopausal bleeding (PMB). However, PMB is not specific for endometrial cancers. In previous reports, the prevalence of endometrial cancer in women with PMB was reported to range from 3-25%. Because of the importance for guiding clinical management and endometrial cancer risk prediction, we conducted a systematic review and meta-analysis to obtain precise prevalence estimates of endometrial cancer in women with PMB. Methods: A systematic review and meta-analysis summarized all peer-reviewed studies reporting endometrial cancer prevalence in women with PMB, published before Sept. 1, 2016. We calculated a pooled prevalence estimate and 95% confidence interval (CI) using a random-effects model, and quantified heterogeneity across studies using the I2 statistic. Subgroup meta-analyses were performed to investigate sources of variability according to selection criteria for endometrial thickness (ET) and hormone replacement therapy (HRT). We also stratified by study location to determine whether prevalence estimates varied by country or region if ≤5 studies included per country. Results: 105 studies were included, contributing data for 37,000 women with PMB and 3,028 with cancer from 34 countries. Overall, the pooled prevalence of endometrial cancer in women with PMB was 11% (95% CI 10-12%), with I2 =94.3%. Among studies that selected women with a minimum ET (≥ 4mm; n=14), the pooled prevalence of endometrial cancer was 17% (95% CI 14-20%) compared with studies that did not select for ET (10%, 95% CI 9-11%). In studies that excluded women using HRT (n=34), the pooled prevalence of endometrial cancer was 15% (95% CI 12-17%) compared with studies that did not exclude women using HRT (9%, 95% CI 8-10%). Stratification by study location revealed variation in prevalence estimates. For example, in the United States (n=9) and the United Kingdom (n=16), prevalence of endometrial cancer was 4% (95% CI 2-7%) and 5% (95% CI 4-6%), respectively, whereas in Italy (n=14), the prevalence was 11% (95% 8-14%). Regional differences were also observed, ranging from 8% (95% CI 3-14%) in South Central Asia (n=5) to 18% (95% CI 12-23%) in Southern Europe (n=11). Conclusions: The overall prevalence of endometrial cancer among unselected women with PMB is approximately 10% with substantial heterogeneity across studies. Marked geographic differences in the prevalence endometrial cancer were observed. Factors related to selection for ET and/or HRT use may partially contribute to this variability. Risk prediction models depend on precise prevalence estimates for accurate prediction and utility in clinical management. More research is needed to test the applicability of endometrial cancer risk prediction models in high-risk subgroups and in study populations from diverse geographic regions. Citation Format: Megan A. Clarke, Beverly J. Long, Arena Del Mar Morillo, Jamie N. Bakkum-Gamez, Nicolas Wentzensen. The prevalence of endometrial cancer in women with postmenopausal bleeding: a systematic review and meta-analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 275. doi:10.1158/1538-7445.AM2017-275