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

Epidermal growth factor receptor ligands enriched in follicular fluid exosomes promote oncogenesis of fallopian tube epithelial cells

BACKGROUND

Incessant ovulation is the main etiologic factor of ovarian high-grade serous carcinomas (HGSC), which mostly originate from the fallopian tube epithelium (FTE). Receptor tyrosine kinase (RTK) ligands essential for follicle development and ovulation wound repair were abundant in the follicular fluid (FF) and promoted the transformation of FTE cells. This study determined whether RTK ligands are present in FF exosomes and whether epidermal growth factor receptor (EGFR) signaling is essential for oncogenic activity.

METHODS

The FF of women undergoing in vitro fertilization was fractionated based on the richness of exosomes and tested for transformation toward FTE cells under different RTK inhibitors. EGFR ligands in FF exosomes were identified, and downstream signaling proteins in FTE cells were characterized.

RESULTS

The transforming activity of FF was almost exclusively enriched in exosomes, which possess a high capacity to induce anchorage-independent growth, clonogenicity, migration, invasion, and proliferation of FTE cells. EGFR inhibition abolished most of these activities. FF and FF exosome exposure markedly increased EGFR phosphorylation and the downstream signal proteins, including AKT, MAPK, and FAK. Multiple EGF family growth factors, such as amphiregulin, epiregulin, betacellulin, and transforming growth factor-alpha, were identified in FF exosomes.

CONCLUSIONS

Our results demonstrate that FF exosomes serve as carriers of EGFR ligands as well as ligands of other RTKs that mediate the transformation of FTE cells and underscore the need to further explore the content and roles of FF exosomes in HGSC development.

ISGylation enhances dsRNA-induced interferon response and NFκB signaling in fallopian tube epithelial cells

Heritable mutations in BRCA1 associate with increased risk of high-grade serous tubo-ovarian cancer. Nongenetic risk factors associated with this cancer, which arises from fallopian tube epithelial (FTE) cells, suggests a role for repetitive ovulation wherein FTE cells are exposed to inflammatory signaling molecules within follicular fluid. We previously reported increased NFκB and EGFR signaling in BRCA1-deficient primary FTE cells, with follicular fluid exposure further increasing abundance of interferon-stimulated gene (ISG) transcripts, including the ubiquitin-like protein ISG15 and other ISGylation pathway members. Both NFκB and type I interferon signaling are upregulated by stimulation of cGAS-STING or MDA5 and RIGI pattern recognition receptors. Since some pattern recognition receptors and their signal transduction pathway members are ISGylated, we tested the impact of ISG15 and ISGylation on interferon regulatory factor 3 (IRF3) and NFκB signaling through cGAS-STING or RIGI and MDA5 activation. Expression of ISG15 or UBA7, the E1-like ISG15-activating enzyme, in immortalized FTE cells was disrupted by CRISPR gene editing. Activation of IRF3 by RIGI or MDA5 but not cGAS-STING was attenuated by loss of either ISG15 or UBA7 and this was reflected by a similar effect on NFκB activation and downstream targets. Loss of ISGylation decreased levels of both MDA5 and RIGI, with knockdown of RIGI but not MDA5, decreasing IRF3 and NFκB activation in parental cells. These finding indicate that ISGylation enhances the ability of dsRNA to activate cytokine release and proinflammatory signaling. Further work to explore ISGylation as a target for prevention of high-grade serous tubo-ovarian cancer in BRCA1 mutation carriers is warranted.

Comparative transcriptomic study on the ovarian cancer between chicken and human

The laying hen is the spontaneous model of ovarian tumor. A comprehensive comparison based on RNA-seq from hens and women may shed light on the molecular mechanisms of ovarian cancer. We performed next-generation sequencing of microRNA and mRNA expression profiles in 9 chicken ovarian cancers and 4 normal ovaries, which has been deposited in GSE246604. Together with 6 public datasets (GSE21706, GSE40376, GSE18520, GSE27651, GSE66957, TCGA-OV), we conducted a comparative transcriptomics study between chicken and human. In the present study, miR-451, miR-2188-5p, and miR-10b-5p were differentially expressed in normal ovaries, early- and late-stage ovarian cancers. We also disclosed 499 up-regulated genes and 1,061 down-regulated genes in chicken ovarian cancer. The molecular signals from 9 cancer hallmarks, 25 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and 369 Gene Ontology (GO) pathways exhibited abnormalities in ovarian cancer compared to normal ovaries via Gene Set Enrichment Analysis (GSEA). In the comparative analysis across species, we have uncovered the conservation of 5 KEGG and 76 GO pathways between chicken and human including the mismatch repair and ECM receptor interaction pathways. Moreover, a total of 174 genes contributed to the core enrichment for these KEGG and GO pathways were identified. Among these genes, the 22 genes were found to be associated with overall survival in patients with ovarian cancer. In general, we revealed the microRNA profiles of ovarian cancers in hens and updated the mRNA profiles previously derived from microarrays. And we also disclosed the molecular pathways and core genes of ovarian cancer shared between hens and women, which informs model animal studies and gene-targeted drug development.

Global epidemiology of epithelial ovarian cancer

Globally, ovarian cancer is the eighth most common cancer in women, accounting for an estimated 3.7% of cases and 4.7% of cancer deaths in 2020. Until the early 2000s, age-standardized incidence was highest in northern Europe and North America, but this trend has changed; incidence is now declining in these regions and increasing in parts of eastern Europe and Asia. Ovarian cancer is a very heterogeneous disease and, even among the most common type, namely epithelial ovarian cancer, five major clinically and genetically distinct histotypes exist. Most high-grade serous ovarian carcinomas are now recognized to originate in the fimbrial ends of the fallopian tube. This knowledge has led to more cancers being coded as fallopian tube in origin, which probably explains some of the apparent declines in ovarian cancer incidence, particularly in high-income countries; however, it also suggests that opportunistic salpingectomy offers an important opportunity for prevention. The five histotypes share several reproductive and hormonal risk factors, although differences also exist. In this Review, we summarize the epidemiology of this complex disease, comparing the different histotypes, and consider the potential for prevention. We also discuss how changes in the prevalence of risk and protective factors might have contributed to the observed changes in incidence and what this might mean for incidence in the future.

Salpingectomy for ectopic pregnancy reduces ovarian cancer risk-a nationwide study

Recent studies propose fallopian tubes as the tissue origin for many ovarian epithelial cancers. To further support this paradigm, we assessed whether salpingectomy for treating ectopic pregnancy had a protective effect using the Taiwan Longitudinal National Health Research Database. We identified 316 882 women with surgical treatment for ectopic pregnancy and 3 168 820 age- and index-date-matched controls from 2000 to 2016. In a nested cohort, 91.5% of cases underwent unilateral salpingectomy, suggesting that most surgically managed patients have salpingectomy. Over a follow-up period of 17 years, the ovarian carcinoma incidence was 0.0069 (95% confidence interval [CI] = 0.0060 to 0.0079) and 0.0089 (95% CI = 0.0086 to 0.0092) in the ectopic pregnancy and the control groups, respectively (P < .001). After adjusting the events to per 100 person-years, the hazard ratio (HR) in the ectopic pregnancy group was 0.70 (95% CI = 0.61 to 0.80). The risk reduction occurred only in epithelial ovarian cancer (HR = 0.73, 95% CI = 0.63 to 0.86) and not in non-epithelial subtypes. These findings show a decrease in ovarian carcinoma incidence after salpingectomy for treating ectopic pregnancy.

Biology-driven therapy advances in high-grade serous ovarian cancer

Following a period of slow progress, the completion of genome sequencing and the paradigm shift relative to the cell of origin for high grade serous ovarian cancer (HGSOC) led to a new perspective on the biology and therapeutic solutions for this deadly cancer. Experimental models were revisited to address old questions, and improved tools were generated. Additional pathways emerging as drivers of ovarian tumorigenesis and key dependencies for therapeutic targeting, in particular, VEGF-driven angiogenesis and homologous recombination deficiency, were discovered. Molecular profiling of histological subtypes of ovarian cancer defined distinct genetic events for each entity, enabling the first attempts toward personalized treatment. Armed with this knowledge, HGSOC treatment was revised to include new agents. Among them, PARP inhibitors (PARPis) were shown to induce unprecedented improvement in clinical benefit for selected subsets of patients. Research on mechanisms of resistance to PARPis is beginning to discover vulnerabilities and point to new treatment possibilities. This Review highlights these advances, the remaining challenges, and unsolved problems in the field.

Pelvic inflammatory disease and risk of epithelial ovarian cancer: a national population-based case-control study in Sweden

BACKGROUND

Epithelial ovarian cancer is an insidious disease, and women are often diagnosed when the disease is beyond curative treatment. Accordingly, identifying modifiable risk factors is of paramount importance. Inflammation predisposes an individual to cancer in various organs, but whether pelvic inflammatory disease is associated with an increased risk of epithelial ovarian cancer has not been fully determined.

OBJECTIVE

This study aimed to investigate a possible association between clinically verified pelvic inflammatory disease and the risk of epithelial ovarian cancer.

STUDY DESIGN

In this national population-based case-control study, all women in Sweden diagnosed with epithelial ovarian cancer between 1999 and 2020 and 10 controls for each were identified, matched for age and residential district. Using several Swedish nationwide registers, data on previous pelvic inflammatory disease and potential confounding factors (age, parity, educational level, and previous gynecologic surgery) were retrieved. Adjusted odds ratios and 95% confidence intervals were estimated using conditional logistic regression. Histotype-specific analyses were performed for the subgroup of women diagnosed with epithelial ovarian cancer between 2015 and 2020. Moreover, hormonal contraceptives and menopausal hormone therapy were adjusted in addition to the aforementioned confounders.

RESULTS

This study included 15,072 women with epithelial ovarian cancer and 141,322 controls. Most women (9102 [60.4%]) had serous carcinoma. In a subgroup of cases diagnosed between 2015 and 2020, high-grade serous carcinoma (2319 [60.0%]) was identified. A total of 168 cases (1.1%) and 1270 controls (0.9%) were diagnosed with pelvic inflammatory disease. Previous pelvic inflammatory disease was associated with an increased risk of epithelial ovarian cancer (adjusted odds ratio, 1.39; 95% confidence interval, 1.17-1.66) and serous carcinoma (adjusted odds ratio, 1.46; 95% confidence interval, 1.18-1.80) for the entire study population. For the subgroup of women diagnosed in 2015-2020, pelvic inflammatory disease was associated with high-grade serous carcinoma (adjusted odds ratio, 1.43; 95% confidence interval, 1.01-2.04). The odds ratios of the other histotypes were as follows: endometrioid (adjusted odds ratio, 0.13; 95% confidence interval, 0.02-1.06), mucinous (adjusted odds ratio, 1.55; 95% confidence interval, 0.56-4.29), and clear cell carcinoma (adjusted odds ratio, 2.30; 95% confidence interval, 0.90-5.86). A dose-response relationship was observed between the number of pelvic inflammatory disease episodes and the risk of epithelial ovarian cancer (Ptrend<.001).

CONCLUSION

A history of pelvic inflammatory disease is associated with an increased risk of epithelial ovarian cancer and a dose-response relationship is evident. Histotype-specific analyses show an association with increased risk of serous epithelial ovarian cancer and high-grade serous carcinoma and potentially also with clear cell carcinoma, but there is no significant association with other histotypes. Infection and inflammation of the upper reproductive tract might have serious long-term consequences, including epithelial ovarian cancer.

Transcriptomic Analysis of the Aged Nulliparous Mouse Ovary Suggests a Stress State That Promotes Pro-Inflammatory Lipid Signaling and Epithelial Cell Enrichment

Ovarian cancer (OC) incidence and mortality peaks at post-menopause while OC risk is either reduced by parity or increased by nulliparity during fertile life. The long-term effect of nulliparity on ovarian gene expression is largely unknown. In this study, we describe a bioinformatic/data-mining analysis of 112 coding genes upregulated in the aged nulliparous (NP) mouse ovary compared to the aged multiparous one as reference. Canonical gene ontology and pathway analyses indicated a pro-oxidant, xenobiotic-like state accompanied by increased metabolism of inflammatory lipid mediators. Up-regulation of typical epithelial cell markers in the aged NP ovary was consistent with synchronized overexpression of Cldn3, Ezr, Krt7, Krt8 and Krt18 during the pre-neoplastic phase of mOSE cell cultures in a former transcriptome study. In addition, 61/112 genes were upregulated in knockout mice for Fshr and for three other tumor suppressor genes (Pten, Cdh1 and Smad3) known to regulate follicular homeostasis in the mammalian ovary. We conclude that the aged NP ovary displays a multifaceted stress state resulting from oxidative imbalance and pro-inflammatory lipid signaling. The enriched epithelial cell content might be linked to follicle depletion and is consistent with abundant clefts and cysts observed in aged human and mouse ovaries. It also suggests a mesenchymal-to-epithelial transition in the mOSE of the aged NP ovary. Our analysis suggests that in the long term, nulliparity worsens a variety of deleterious effects of aging and senescence thereby increasing susceptibility to cancer initiation in the ovary.

Early-Onset Ovarian Cancer <30 Years: What Do We Know about Its Genetic Predisposition?

Ovarian cancer (OC) is one of the leading causes of cancer-related deaths in women. Most patients are diagnosed with advanced epithelial OC in their late 60s, and early-onset adult OC diagnosed ≤30 years is rare, accounting for less than 5% of all OC cases. The most significant risk factor for OC development are germline pathogenic/likely pathogenic variants (GPVs) in OC predisposition genes (including BRCA1, BRCA2, BRIP1, RAD51C, RAD51D, Lynch syndrome genes, or BRIP1), which contribute to the development of over 20% of all OC cases. GPVs in BRCA1/BRCA2 are the most prevalent. The presence of a GPV directs tailored cancer risk-reducing strategies for OC patients and their relatives. Identification of OC patients with GPVs can also have therapeutic consequences. Despite the general assumption that early cancer onset indicates higher involvement of hereditary cancer predisposition, the presence of GPVs in early-onset OC is rare (<10% of patients), and their heritability is uncertain. This review summarizes the current knowledge on the genetic predisposition to early-onset OC, with a special focus on epithelial OC, and suggests other alternative genetic factors (digenic, oligogenic, polygenic heritability, genetic mosaicism, imprinting, etc.) that may influence the development of early-onset OC in adult women lacking GPVs in known OC predisposition genes.

Microfluidic platforms in diagnostic of ovarian cancer

The most important reason for death from ovarian cancer is the late diagnosis of this disease. The standard treatment of ovarian cancer includes surgery and chemotherapy based on platinum, which is associated with side effects for the body. Due to the nonspecific nature of clinical symptoms, developing a platform for early detection of this disease is needed. In recent decades, the advancements of microfluidic devices and systems have provided several advantages for diagnosing ovarian cancer. Designing and manufacturing new platforms using specialized technologies can be a big step toward improving the prevention, diagnosis, and treatment of this group of diseases. Organ-on-a-chip microfluidic devices are increasingly used as a promising platform in cancer research, with a focus on specific biological aspects of the disease. This review focusing on ovarian cancer and microfluidic application technologies in its diagnosis. Additionally, it discusses microfluidic platforms and their potential future perspectives in advancing ovarian cancer diagnosis.

Estimated Ovulatory Years Prior to Menopause and Postmenopausal Endogenous Hormone Levels

BACKGROUND

Lifetime ovulatory years (LOY) is estimated by the difference between ages at menopause and menarche subtracting time for events interrupting ovulation. We tested whether LOY influences sex hormone levels in postmenopausal women with at least one intact ovary not using hormones.

METHODS

Estradiol, estrone, estrone sulfate, total testosterone, dehydroepiandrostendione sulfate, prolactin, and sex hormone binding globulin were measured in 1,976 postmenopausal women from the Nurses' Health Study. Associations of age, body mass index (BMI), smoking, alcohol use, and other factors on hormones were assessed by t tests and ANOVA. Linear regression was used to assess multivariable adjusted associations between LOY and hormones and trends in hormone levels per 5-year increases in LOY were estimated.

RESULTS

Women averaged 61.4 years old, 11.0 years since menopause, with BMI of 25.8 kg/m2. A total of 13.6% had irregular cycles, 17.5% hysterectomy, 6.4% unilateral oophorectomy, and 13.8% were current smokers. Variables associated with one or more hormone levels were included as covariates. Each 5-year increase in LOY was significantly associated with a 5.2% increase in testosterone in women with BMI < 25 kg/m2 and a 7.4% increase in testosterone and 7.3% increase in estradiol in women with above-average BMI.

CONCLUSIONS

This is the first study to show that greater LOY is associated with higher testosterone in postmenopausal women and higher estradiol in those with elevated BMI, suggesting accumulation of functioning stromal and thecal cells from repeated ovulations and peripheral conversion of testosterone.

IMPACT

A possible explanation for why greater LOY increases risk for breast, endometrial, and ovarian cancer is offered.