scholarly journals Appraising the role of previously reported risk factors in epithelial ovarian cancer risk: A Mendelian randomization analysis

PLoS Medicine ◽  
2019 ◽  
Vol 16 (8) ◽  
pp. e1002893 ◽  
Author(s):  
James Yarmolinsky ◽  
Caroline L. Relton ◽  
Artitaya Lophatananon ◽  
Kenneth Muir ◽  
Usha Menon ◽  
...  
2018 ◽  
Author(s):  
James Yarmolinsky ◽  
Caroline L Relton ◽  
Artitaya Lophatananon ◽  
Kenneth Muir ◽  
Usha Menon ◽  
...  

AbstractBackgroundVarious modifiable risk factors have been associated with epithelial ovarian cancer risk in observational epidemiological studies. However, the causal nature of the risk factors reported, and thus their suitability as effective intervention targets, is unclear given the susceptibility of conventional observational designs to residual confounding and reverse causation. Mendelian randomization uses genetic variants as proxies for modifiable risk factors to strengthen causal inference in observational studies. We used Mendelian randomization to evaluate the causal role of 13 previously reported risk factors (reproductive, anthropometric, clinical, lifestyle, and molecular factors) in overall and histotype-specific epithelial ovarian cancer in up to 25,509 case subjects and 40,941 controls in the Ovarian Cancer Association Consortium.Methods and FindingsGenetic instruments to proxy 13 risk factors were constructed by identifying single nucleotide polymorphisms (SNPs) robustly (P<5×10−8) and independently associated with each respective risk factor in previously reported genome-wide association studies. SNPs were combined into multi-allelic inverse-variance weighted fixed or random-effects models to generate causal estimates. Three complementary sensitivity analyses were performed to examine violations of Mendelian randomization assumptions: MR-Egger regression and weighted median and mode estimators. A Bonferroni-corrected P-value threshold was used to establish “strong evidence” (P<0.0038) and “suggestive evidence” (0.0038<P<0.05) for associations.In Mendelian randomization analyses, there was strong or suggestive evidence that 9 of 13 risk factors had a causal effect on overall or histotype-specific epithelial ovarian cancer. There was strong evidence that genetic liability to endometriosis increased risk of epithelial ovarian cancer (OR per log odds higher liability:1.27, 95% CI: 1.16-1.40; P=6.94×10−7) and suggestive evidence that lifetime smoking exposure increased risk of epithelial ovarian cancer (OR per unit increase in smoking score:1.36, 95% CI: 1.04-1.78; P=0.02). In histotype-stratified analyses, the strongest associations found were between: height and clear cell carcinoma (OR per SD increase:1.36, 95% CI: 1.15-1.61; P=0.0003); age at natural menopause and endometrioid carcinoma (OR per year later onset:1.09, 95% CI: 1.02-1.16; P=0.007); and genetic liability to polycystic ovary syndrome and endometrioid carcinoma (OR per log odds higher liability:0.74, 95% CI:0.62-0.90; P=0.002). There was little evidence for an effect of genetic liability to type 2 diabetes, parity, or circulating levels of 25-hydroxyvitamin D and sex hormone-binding globulin on ovarian cancer or its subtypes. The primary limitations of this analysis include: modest statistical power for analyses of risk factors in relation to some less common ovarian cancer histotypes (low grade serous, mucinous, and clear cell carcinomas), the inability to directly examine the causal effects of some ovarian cancer risk factors that did not have robust genetic variants available to serve as proxies (e.g., oral contraceptives, hormone replacement therapy), and the assumption of linear relationships between risk factors and ovarian cancer risk.ConclusionsOur comprehensive examination of possible etiological drivers of ovarian carcinogenesis using germline genetic variants to proxy risk factors supports a causal role for few of these factors in epithelial ovarian cancer and suggests distinct etiologies across histotypes. The identification of novel modifiable risk factors remains an important priority for the control of epithelial ovarian cancer.


2013 ◽  
Vol 109 (3) ◽  
pp. 769-776 ◽  
Author(s):  
C Bodelon ◽  
N Wentzensen ◽  
S J Schonfeld ◽  
K Visvanathan ◽  
P Hartge ◽  
...  

2019 ◽  
Vol 8 (8) ◽  
pp. 4012-4022 ◽  
Author(s):  
Huijun Yang ◽  
Hongji Dai ◽  
Lian Li ◽  
Xin Wang ◽  
Peishan Wang ◽  
...  

2021 ◽  
Author(s):  
Emma Hazelwood ◽  
Eleanor Sanderson ◽  
Vanessa Y Tan ◽  
Katherine S Ruth ◽  
Timothy M Frayling ◽  
...  

Background: Endometrial cancer is the most common gynaecological cancer in high-income countries. Elevated body mass index (BMI) is an established modifiable risk factor for this condition and is estimated to confer a larger effect on endometrial cancer risk than any other cancer site. However, the molecular mechanisms underpinning this association remain unclear. We used Mendelian randomization (MR) to evaluate the causal role of 14 molecular risk factors (hormonal, metabolic, and inflammatory markers) in endometrial cancer risk. We then evaluated and quantified the potential mediating role of these molecular traits in the relationship between BMI and endometrial cancer. Methods and Findings: Genetic instruments to proxy 14 molecular risk factors and BMI were constructed by identifying single-nucleotide polymorphisms (SNPs) reliably associated (P < 5.0 x 10-8) with each respective risk factor in previous genome-wide association studies (GWAS). Summary statistics for the association of these SNPs with overall and subtype-specific endometrial cancer risk (12,906 cases and 108,979 controls) were obtained from a GWAS meta-analysis of the Endometrial Cancer Association Consortium (ECAC), Epidemiology of Endometrial Cancer Consortium (E2C2), and UK Biobank. SNPs were combined into multi-allelic models and odds ratios (ORs) and 95% confidence intervals (95% CIs) were generated using inverse-variance weighted random-effects models. The mediating roles of the molecular risk factors in the relationship between BMI and endometrial cancer were then estimated using multivariable MR. In MR analyses, there was strong evidence that BMI (OR per SD increase: 1.88, 95% CI: 1.69 to 2.09, P = 3.87 x 10-31), total testosterone (OR per inverse normal transformed nmol/L increase: 1.64, 95% CI: 1.43 to 1.88, P = 1.71 x 10-12), bioavailable testosterone (OR per inverse normal transformed nmol/L increase: 1.46, 95% CI: 1.29 to 1.65, P = 3.48 x 10-9), fasting insulin (OR per natural log transformed pmol/L increase: 3.93, 95% CI: 2.29 to 6.74, P = 7.18 x 10-7) and sex hormone-binding globulin (SHBG, OR per inverse normal transformed nmol/L increase: 0.71, 95% CI: 0.59 to 0.85, P = 2.07 x 10-4) had a causal effect on endometrial cancer risk. Additionally, there was suggestive evidence that total serum cholesterol (OR per mg/dL increase: 0.90, 95% CI: 0.81 to 1.00, P = 4.01 x 10-2) had an effect on endometrial cancer risk. In mediation analysis using multivariable MR, we found evidence for a mediating role of fasting insulin (19% total effect mediated, 95% CI: 5 to 34%, P = 9.17 x 10-3), bioavailable testosterone (15% mediated, 95% CI: 10 to 20%, P = 1.43 x 10-8), and SHBG (7% mediated, 95% CI: 1 to 12%, P = 1.81 x 10-2) in the relationship between BMI and endometrial cancer risk. The primary limitations of this analysis include the assumption of linear relationships across univariable and multivariable analyses and the restriction of analyses to individuals of European ancestry. Conclusions: Our comprehensive Mendelian randomization analysis provides insight into potential causal mechanisms linking BMI with endometrial cancer risk and suggests pharmacological targeting of insulinemic and hormonal traits as a potential strategy for the prevention of endometrial cancer.


2018 ◽  
Vol 10 (2) ◽  
pp. 337-346 ◽  
Author(s):  
Mary Kathleen Ladd ◽  
Beth N Peshkin ◽  
Leigha Senter ◽  
Shari Baldinger ◽  
Claudine Isaacs ◽  
...  

Abstract Risk-reducing mastectomy (RRM) and salpingo-oophorectomy (RRSO) are increasingly used to reduce breast and ovarian cancer risk following BRCA1/BRCA2 testing. However, little is known about how genetic counseling influences decisions about these surgeries. Although previous studies have examined intentions prior to counseling, few have examined RRM and RRSO intentions in the critical window between genetic counseling and test result disclosure. Previous research has indicated that intentions at this time point predict subsequent uptake of surgery, suggesting that much decision-making has taken place prior to result disclosure. This period may be a critical time to better understand the drivers of prophylactic surgery intentions. The aim of this study was to examine predictors of RRM and RRSO intentions. We hypothesized that variables from the Health Belief Model would predict intentions, and we also examined the role of affective factors. Participants were 187 women, age 21–75, who received genetic counseling for hereditary breast and ovarian cancer. We utilized multiple logistic regression to identify independent predictors of intentions. 49.2% and 61.3% of participants reported intentions for RRM and RRSO, respectively. Variables associated with RRM intentions include: newly diagnosed with breast cancer (OR = 3.63, 95% CI = 1.20–11.04), perceived breast cancer risk (OR = 1.46, 95% CI = 1.17–1.81), perceived pros (OR = 1.79, 95% CI = 1.38–2.32) and cons of RRM (OR = 0.81, 95% CI = 0.65–0.996), and decision conflict (OR = 0.80, 95% CI = 0.66–0.98). Variables associated with RRSO intentions include: proband status (OR = 0.28, 95% CI = 0.09–0.89), perceived pros (OR = 1.35, 95% CI = 1.11–1.63) and cons of RRSO (OR = 0.72, 95% CI = 0.59–0.89), and ambiguity aversion (OR = 0.79, 95% CI = 0.65–0.95). These data provide support for the role of genetic counseling in fostering informed decisions about risk management, and suggest that the role of uncertainty should be explored further.


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