Prospective study of body fat distribution and the risk of endometrial cancer

The Association Between Nutrition, Obesity, Inflammation, and Endometrial Cancer: A Scoping Review

PURPOSE OF REVIEW

Endometrial cancer is the most common gynecological malignancy and represents a notorious threat to women's health worldwide. Endometrial cancer predominantly affects post-menopausal women; yet the prevalence of this disease has been rising also among pre-menopausal women. Poor nutritional habits, inflammation, and obesity may be associated with endometrial cancer (EC) among both pre-menopausal and post-menopausal women and should be further assessed among a wide spectrum of age groups.

RECENT FINDINGS

This scoping review explores and reports on primary research studies conducted to investigate the impact of nutrition, inflammation, and/or obesity on endometrial cancer risk among both pre-menopausal and post-menopausal women. Using a predefined protocol in compliance with the PRISMA guidelines, a search was conducted on four separate databases including PubMed, Cochrane Library, ProQuest, and Google Scholar to investigate the association between nutrition, inflammation, obesity, and endometrial cancer. A total of 4862 articles were identified. Following a full article analysis, 27 articles met the full inclusion criteria and were included in the current review. Findings from the literature support a role of nutrition, obesity, and inflammation in the development of EC. The studies included in the current review supported that plant-based, Mediterranean, or ketogenic diets are associated with a lower risk of EC while there is no association between glycemic index and EC risk. On the other hand, increased BMI is associated with a higher risk of EC and there is a positive association between obesity-related pro-inflammatory biomarkers and increased risk for EC development. Further research needs to be conducted to gain more insight into the complex interactions between nutrition, obesity, and inflammation and their association with EC development among pre-, peri-, and post- menopausal women with the ultimate goal to improve management and preventive strategies and achieve reduced prevalence of endometrial cancer.

Body size, body composition and endometrial cancer risk among postmenopausal women in UK Biobank

Previous studies on the association of adiposity with endometrial cancer risk have mostly used body mass index (BMI) as the main exposure of interest. Whether more precise measures of body fat, such as body fat percentage and fat mass estimated by bioimpedance analyses, are better indicators of risk than BMI is unknown. The role of central adiposity and fat-free mass in endometrial cancer development remains unclear. We used Cox regression models to estimate hazard ratios (HR) and corresponding 95% confidence intervals (CI) for the associations of various measures of body size/composition with the risk of endometrial cancer among 135 110 postmenopausal women enrolled in UK Biobank. During a mean follow up of 6.8 years, 706 endometrial cancers were diagnosed, with a mean age at diagnosis of 65.5 years. The HRs (95% CIs) for endometrial cancer per 1 SD increase in BMI, body fat percentage and fat mass were broadly comparable, being 1.71 (1.61-1.82), 1.92 (1.75-2.11) and 1.73 (1.63-1.85), respectively. There was an indication of positive association between central adiposity, as reflected by waist circumference (HRper 1-SD increase = 1.08, 95% CI: 1.00-1.17) and waist to hip ratio (HRper 1-SD increase = 1.13, 95% CI: 1.01-1.26), and endometrial cancer risk after accounting for BMI. Fat-free mass was not an independent predictor of risk in this cohort. These findings suggest that body fat percentage and fat mass are not better indicators of endometrial cancer risk than BMI. Further studies are needed to establish whether central adiposity contributes to risk beyond overall adiposity.

Pterostilbene suppresses human endometrial cancer cells in vitro by down-regulating miR-663b

Resveratrol has long been known as an antioxidant and a chemopreventive agent. Similar to resveratrol, pterostilbene (PT) is also a phenolic compound extracted from the Vitis species. However, there are few studies on the antitumor effect of PT. Thus, we investigated the effects of PT on the endometrial cancer (EC) cells in vitro and the related molecular mechanisms. Treatment of EC cell lines HTB-111 and Ishikawa with PT (25-100 μmol/L) dose-dependently suppressed the cell viability and induced apoptosis. Using miR microarrays, we examined the miR expression profile in Ishikawa cells with or without PT, and revealed that miR-663b was the most decreased in PT-treated Ishikawa cells. Furthermore, we predicted and verified that the pro-apoptosis factor BCL2L14 is the direct target of miR-663b. Over-expression of miR-663b and knock-down of BCL2L14 counteracted the suppressing effects of PT on HTB-111 and Ishikawa cells. In addition, we evaluated the miR-663b levels in EC tissues of 51 patients using an in situ hybridization technique. With the median of the score of miR-663b as a cut-off value, these EC patients were divided into two groups, and the patients with high miR-663b expression had significantly poor prognosis.

Body size over the life-course and the risk of endometrial cancer: the California Teachers Study

PURPOSE

Obesity is a public health epidemic and a major risk factor for endometrial cancer. Here, we identify key aspects of body size which jointly, over the life-course (since adolescence), are associated with endometrial cancer risk.

METHODS

Among 88,142 participants in the California Teachers Study, 887 were diagnosed with invasive type 1 endometrial cancer between 1997-1998 and 2012. Multivariable Cox proportional hazards models provided estimates of hazard rate ratios (HR) and 95% confidence intervals (CI) for endometrial cancer associated with life-course body size phenotypes, which incorporated validated measures.

RESULTS

Among women currently using hormone therapy, endometrial cancer risk was only associated with height (HR 1.78, 95% CI 1.32-2.40 for ≥67 vs. <67 inches). Among women not using hormone therapy, tall women who were overweight/obese in adolescence (HR 4.33, 95% CI 2.51-7.46) or who became overweight/obese as adults (HR 4.74, 95% CI 2.70-8.32) were at greatest risk.

CONCLUSIONS

Considering absolute body mass, changes in adiposity over time, and body fat distribution together, instead of each measure alone, we identified lifetime obesity phenotypes associated with endometrial cancer risk. These results more clearly define specific risk groups, and may explain inconsistent findings across studies, improve risk prediction models, and aid in developing targeted interventions for endometrial cancer.

Genetic Risk Score Mendelian Randomization Shows that Obesity Measured as Body Mass Index, but not Waist:Hip Ratio, Is Causal for Endometrial Cancer

BACKGROUND

The strongest known risk factor for endometrial cancer is obesity. To determine whether SNPs associated with increased body mass index (BMI) or waist-hip ratio (WHR) are associated with endometrial cancer risk, independent of measured BMI, we investigated relationships between 77 BMI and 47 WHR SNPs and endometrial cancer in 6,609 cases and 37,926 country-matched controls.

METHODS

Logistic regression analysis and fixed effects meta-analysis were used to test for associations between endometrial cancer risk and (i) individual BMI or WHR SNPs, (ii) a combined weighted genetic risk score (wGRS) for BMI or WHR. Causality of BMI for endometrial cancer was assessed using Mendelian randomization, with BMIwGRS as instrumental variable.

RESULTS

The BMIwGRS was significantly associated with endometrial cancer risk (P = 3.4 × 10-17). Scaling the effect of the BMIwGRS on endometrial cancer risk by its effect on BMI, the endometrial cancer OR per 5 kg/m2 of genetically predicted BMI was 2.06 [95% confidence interval (CI), 1.89-2.21], larger than the observed effect of BMI on endometrial cancer risk (OR = 1.55; 95% CI, 1.44-1.68, per 5 kg/m2). The association attenuated but remained significant after adjusting for BMI (OR = 1.22; 95% CI, 1.10-1.39; P = 5.3 × 10-4). There was evidence of directional pleiotropy (P = 1.5 × 10-4). BMI SNP rs2075650 was associated with endometrial cancer at study-wide significance (P < 4.0 × 10-4), independent of BMI. Endometrial cancer was not significantly associated with individual WHR SNPs or the WHRwGRS.

CONCLUSIONS

BMI, but not WHR, is causally associated with endometrial cancer risk, with evidence that some BMI-associated SNPs alter endometrial cancer risk via mechanisms other than measurable BMI.

IMPACT

The causal association between BMI SNPs and endometrial cancer has possible implications for endometrial cancer risk modeling. Cancer Epidemiol Biomarkers Prev; 25(11); 1503-10. ©2016 AACR.

Role of MicroRNAs in carcinogenesis that potential for biomarker of endometrial cancer

The non-invasive diagnostic tool for early detection of endometrial cancer still limited. The etiology of this disease is believed to be associated with disharmony hormone production. One predominant factor that regulate hormone production is microRNA (miRNAs). Some studies reported that miRNAs play a significant role in the process carcinogenesis. We have identified 12 of miRNAs that potentially have a role in controlling endometrial carcinogenesis pathways. Further analysis suggested that these miRNA targeted genes that regulate the early development of endometrial cancer. These genes cluster into several functional groups involving a process of angiogenesis, apoptosis, cell cycle, cell proliferation and p53 pathways. Some of the genes are PTEN, GSK3b, and TP53, which are a tumor suppressor that control the process of growth arrest, DNA Repair, and Apoptosis. Upregulation of the miRNA may obstruct the cell ability to control the cell cycle. This study was found three miRNA that plays a role in the development of endometrial cancer. The hsa-miR-495 and hsa-miR-152 were repressed in endometrial cancer compared to normal tissue. The microRNA regulate genes that control proliferation and cell survival. Moreover, hsa-miR-181d was upregulated to control expression a tumor suppressor gene, PTEN to protect the cancer cell from apoptosis. Further investigation to validate the function of the miRNA is a warrant for developing biomarkers of endometrial carcinoma.

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Three miRNA may controlled genes that regulate early development of endometrial cancer.

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PTEN is central gene of endometrial cancer that targeted by the miRNA.

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The miRNA and PTEN are potential for a biomarker of early detection of endometrial cancer.