A prospective evaluation of insulin and insulin-like growth factor-I as risk factors for endometrial cancer

Endometrial Cancer in Reproductive-Aged Females: Etiology and Pathogenesis

Endometrial cancer is the most common gynecologic malignancy in developed countries, and the incidence is rising in premenopausal females. Type I EC is more common than Type II EC (80% vs. 20%) and is associated with a hyperestrogenic state. Estrogen unopposed by progesterone is considered to be the main driving factor in the pathogenesis of EC. Studies show that BMI > 30 kg/m2, prolonged duration of menses, nulliparity, presence of polycystic ovarian syndrome, and Lynch syndrome are the most common causes of EC in premenopausal women. Currently, there are no guidelines established to indicate premenopausal patients who should be screened. This review aims to synthesize current data on the etiology, risk factors, presentation, evaluation, and prognosis of endometrial cancer in this population.

Horizons in Endometriosis: Proceedings of the Montreux Reproductive Summit, 14-15 July 2023

Endometriosis is a complex and chronic gynaecological disorder that affects millions of women worldwide, leading to significant morbidity and impacting reproductive health. This condition affects up to 10% of women of reproductive age and is characterised by the presence of endometrial-like tissue outside the uterus, potentially leading to symptoms such as chronic pelvic pain, dysmenorrhoea, dyspareunia, and infertility. The Montreux summit brought a number of experts in this field together to provide a platform for discussion and exchange of ideas. These proceedings summarise the six main topics that were discussed at this summit to shed light on future directions of endometriosis classification, diagnosis, and therapeutical management. The first question addressed the possibility of preventing endometriosis in the future by identifying risk factors, genetic predispositions, and further understanding of the pathophysiology of the condition to develop targeted interventions. The clinical presentation of endometriosis is varied, and the correlation between symptoms severity and disease extent is unclear. While there is currently no universally accepted optimal classification system for endometriosis, several attempts striving towards its optimisation - each with its own advantages and limitations - were discussed. The ideal classification should be able to reconcile disease status based on the various diagnostic tools, and prognosis to guide proper patient tailored management. Regarding diagnosis, we focused on future tools and critically discussed emerging approaches aimed at reducing diagnostic delay. Preserving fertility in endometriosis patients was another debatable aspect of management that was reviewed. Moreover, besides current treatment modalities, potential novel medical therapies that can target underlying mechanisms, provide effective symptom relief, and minimise side effects in endometriotic patients were considered, including hormonal therapies, immunomodulation, and regenerative medicine. Finally, the question of hormonal substitution therapy after radical treatment for endometriosis was debated, weighing the benefits of hormone replacement.

Circulating Adipocytokines and Insulin Like-Growth Factors and Their Modulation in Obesity-Associated Endometrial Cancer

The rising global incidence of uterine cancer is linked to the escalating prevalence of obesity. Obesity results in alterations in adipocytokines and IGFs, driving cancer progression via inflammation, increased cell proliferation, and apoptosis inhibition, although the precise mechanisms are still unclear. This study examined a set of six markers, namely, adiponectin, leptin, IL6, TNFα, IGF1, and IGF2 and compared them between fifty age-matched endometrial cancer patients (study group) and non-cancer patients with benign gynaecological conditions (control group). We also assessed the relationship of these markers with obesity and explored the correlation between these markers and various tumour characteristics. In the cancer population, these markers were also assessed 24 h and 6 months post-surgery. Remarkably, low adiponectin levels were associated with a 35.8% increase in endometrial cancer risk. Interestingly, compared to control subjects where IGF levels decreased after menopause, post-menopausal women in the study group showed elevated IGF1 and IGF2 levels, suggesting a potential influence of endometrial cancer on the IGF system, particularly after menopause. Lastly, it is noteworthy that a discernible inverse relationship trend was observed in the levels of adipocytokines and IGFs 6 months post-surgery. This indicates that treatment for endometrial cancer may have a differential impact on adipocytokines and IGFs, potentially holding clinical significance that merits further investigation.

Mediterranean diet and olive oil, microbiota, and obesity-related cancers. From mechanisms to prevention

Olive oil (OO) is the main source of added fat in the Mediterranean diet (MD). It is a mix of bioactive compounds, including monounsaturated fatty acids, phytosterols, simple phenols, secoiridoids, flavonoids, and terpenoids. There is a growing body of evidence that MD and OO improve obesity-related factors. In addition, obesity has been associated with an increased risk for several cancers: endometrial, oesophageal adenocarcinoma, renal, pancreatic, hepatocellular, gastric cardia, meningioma, multiple myeloma, colorectal, postmenopausal breast, ovarian, gallbladder, and thyroid cancer. However, the epidemiological evidence linking MD and OO with these obesity-related cancers, and their potential mechanisms of action, especially those involving the gut microbiota, are not clearly described or understood. The goals of this review are 1) to update the current epidemiological knowledge on the associations between MD and OO consumption and obesity-related cancers, 2) to identify the gut microbiota mechanisms involved in obesity-related cancers, and 3) to report the effects of MD and OO on these mechanisms.

Transcriptomic analysis identifies four novel receptors potentially linking endometrial cancer with polycystic ovary syndrome and generates a transcriptomic atlas

Polycystic Ovary Syndrome (PCOS) is associated with a 3 to 4-fold increased risk of endometrial cancer (EC), but molecular mechanisms are unclear. Upregulation of the IGF1 gene in PCOS endometrium may increase EC risk, but this is uncertain. We aimed to investigate links between EC and PCOS, by analysing publicly available transcriptomic data. The NCBI Gene Expression Omnibus was used to identify relevant studies. Differentially expressed genes (DEGs) were identified and analysed using Metascape to identify pathways of interest. PCOS DEGs that encode proteins secreted into blood were identified using the Human Protein Atlas blood protein database. EC DEGs that are cellular receptors were identified using EcoTyper. These were intersected to identify which EC receptors interact with PCOS secreted proteins. Seven receptors were identified in EC but only PTPRF, ITGA2, ITGA3 and ITGB4 genes were expressed on epithelial cells. Pathway enrichment of these genes showed that the major and common pathway involved was that of the PI3K-AKT signalling pathway which was consistent with a link between PCOS and EC. However, IGF1 was down regulated in PCOS and EC. These findings hold significant promise for improving our understanding of mechanistic pathways leading to EC in PCOS.

Ketogenic Diet as a Possible Non-pharmacological Therapy in Main Endocrine Diseases of the Female Reproductive System: A Practical Guide for Nutritionists

PURPOSEOF REVIEW

This narrative review explored the role of ketogenic diets (KDs) in improving fertility outcomes, low-grade inflammation, body weight, visceral adipose tissue, and its potential use in certain types of cancer, through its favorable actions on mitochondrial function, reactive oxygen species generation, chronic inflammation, and tumor growth inhibition. RECENT FINDINGS  : Nutrition is crucial to maintain the female reproductive system's health. Evidence on the association between diet and female reproductive system has greatly expanded over the last decade, leading to the identification of specific diet therapy, particularly KDs. KDs has been proved to be an effective weight-loss tool. To date, KDs is being increasingly used in the treatment of many diseases, such as obesity, type 2 diabetes mellitus. KDs is a dietary intervention capable of ameliorating the inflammatory state and oxidative stress through several mechanisms. Due to the increasing use of KDs beyond obesity, this literature review will provide the latest scientific evidence of its possible use in common disorders of the female endocrine-reproductive tract, and a practical guide to its use in these patients.

Inflammatory and insulinemic dietary patterns and risk of endometrial cancer among US women

BACKGROUND

Although unopposed estrogen exposure is considered a major driver of endometrial carcinogenesis, chronic inflammation and insulin resistance and hyperinsulinemia are also major endometrial cancer risk factors. However, it is unclear whether diets with inflammatory or insulinemic potential are associated with risk of endometrial cancer.

METHODS

We followed 48 330 women from the Nurses' Health Study (1984-2016) and 85 426 women from the Nurses' Health Study II (1989-2017). Using food frequency questionnaires, we calculated repeated measures of empirical dietary inflammatory pattern (EDIP) and empirical dietary index for hyperinsulinemia (EDIH) scores, which characterize the potential of the whole diet to modulate circulating biomarkers of inflammation or C-peptide, respectively. We used multivariable-adjusted Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for type I endometrial cancer risk.

RESULTS

We documented 1462 type I endometrial cancer cases over 2 823 221 person-years of follow-up. In the pooled multivariable-adjusted analyses, women in the highest compared with lowest quintiles were at higher risk of type I endometrial cancer (EDIP HRQ5vsQ1 = 1.46, 95% CI = 1.24 to 1.73; Ptrend < .001; EDIH HRQ5vsQ1 = 1.58, 95% CI = 1.34 to 1.87; Ptrend < .001). Additional adjustment for body mass index attenuated the associations (EDIP HR = 1.03, 95% CI = 0.87 to 1.22; EDIH HR = 1.01, 95% CI = 0.85 to 1.21), and mediation analyses showed that body mass index may explain 60.4% (95% CI = 37.4% to 79.6%; P < .001) and 71.8% (95% CI = 41.0% to 90.4%; P < .001) of the association of endometrial cancer with EDIP and EDIH, respectively.

CONCLUSIONS

In this large cohort study, higher dietary inflammatory and insulinemic potential were each associated with increased endometrial cancer incidence, and this association may be almost entirely mediated by adiposity.

Bidirectional Mendelian randomization study of insulin-related traits and risk of ovarian cancer

BACKGROUND

It is well known that the occurrence and development of ovarian cancer are closely related to the patient's weight and various endocrine factors in the body.

AIM

Mendelian randomization (MR) was used to analyze the bidirectional relationship between insulin related characteristics and ovarian cancer.

METHODS

The data on insulin related characteristics are from up to 5567 diabetes free patients from 10 studies, mainly including fasting insulin level, insulin secretion rate, peak insulin response, etc. For ovarian cancer, UK Biobank data just updated in 2021 was selected, of which the relevant gene data was from 199741 Europeans. Mendelian randomization method was selected, with inverse variance weighting (IVW) as the main estimation, while MR Pleiotropy, MR Egger, weighted median and other methods were used to detect the heterogeneity of data and whether there was multi validity affecting conclusions.

RESULTS

Among all insulin related indicators (fasting insulin level, insulin secretion rate, peak insulin response), the insulin secretion rate was selected to have a causal relationship with the occurrence of ovarian cancer (IVW, P < 0.05), that is, the risk of ovarian cancer increased with the decrease of insulin secretion rate. At the same time, we tested the heterogeneity and polymorphism of this indicator, and the results were non-existent, which ensured the accuracy of the analysis results. Reverse causal analysis showed that there was no causal effect between the two (P>0.05).

CONCLUSION

The impairment of the insulin secretion rate has a causal effect on the risk of ovarian cancer, which was confirmed by Mendel randomization. This suggests that the human glucose metabolism cycle represented by insulin secretion plays an important role in the pathogenesis of ovarian cancer, which provides a new idea for preventing the release of ovarian cancer.

Body fatness associations with cancer: evidence from recent epidemiological studies and future directions

This narrative review highlights current evidence linking greater body fatness to risk of various cancers, with focus on evidence from recent large cohort studies and pooled analyses of cohort studies as well as Mendelian randomization studies (which utilized genetic variants associated with body mass index to debrief the causal effect of higher body fatness on cancer risk). This review also provides insights into the biological mechanisms underpinning the associations. Data from both observational and Mendelian randomization studies support the associations of higher body mass index with increased risk of many cancers with the strongest evidence for digestive system cancers, including esophageal, stomach, colorectal, liver, gallbladder, and pancreatic cancer, as well as kidney, endometrial, and ovarian (weak association) cancer. Evidence from observational studies suggests that greater body fatness has contrasting effects on breast cancer risk depending on menopausal status and on prostate cancer risk depending on disease stage. Experimental and Mendelian randomization studies indicate that adiponectin, insulin, and sex hormone pathways play an important role in mediating the link between body fatness and cancer risk. The possible role of specific factors and pathways, such as other adipocytokines and hormones and the gut microbiome in mediating the associations between greater body fatness and cancer risk is yet uncertain and needs investigation in future studies. With rising prevalence of overweight and obesity worldwide, the proportion of cancer caused by excess body fatness is expected to increase. There is thus an urgent need to identify efficient ways at the individual and societal level to improve diet and physical activity patterns to reduce the burden of obesity and accompanying comorbidities, including cancer.

Epidemiological trends of female breast and gynecologic cancers in adolescents and young adults in China from 1990 to 2019: Results from the Global Burden of Disease Study 2019

Background

Research on the incidence, mortality, and disability-adjusted life years (DALYs) of female breast and gynecologic cancers (FeBGCs) and the relevant risk factors for adolescents and young adults (AYAs) are valuable for policy-making in China. We aimed to estimate the incidence, deaths, and DALYs and predict epidemiological trends of FeBGCs among AYAs in China between 1990 and 2019.

Methods

Data from the 2019 Global Burden of Disease (GBD) study between 1990 and 2019 in 195 countries and territories were retrieved. Data about the number of FeBGC incident cases, deaths, DALYs, age-standardized rates (ASRs), and estimated annual percentage changes (EAPCs) were extracted. A comparative risk assessment framework was performed to estimate the risk factors attributable to breast cancer deaths and DALYs, and autoregressive integrated moving average (ARIMA) models were fitted for time-series analysis to predict female cancer morbidity and mortality among Chinese AYAs until 2030.

Results

In 2019, there are 61,038 incidence cases, 8,944 deaths, and 529,380 DALYs of FeBGCs among the AYAs in China, respectively. The estimated annual percentage change (EAPC) values were positive scores (>0) in ASIRs and negative scores (<0) in ASMR and ASDR. Furthermore, in 2030, the incidence rate of FeBGCs would grow to 30.49 per 100,000 in China, while the mortality rate would maintain a steady state. Of the deaths and DALYs, diet high in red meat was the greatest contributor to breast cancer, while a high body mass index (BMI) was the greatest contributor to cervical, ovarian, and uterine cancers.

Conclusion

The increasing Chinese FeBGC burden is mainly observed in AYAs and non-red meat diet, and the control of body weight could reduce FeBGC burden in China.

Cigarette Smoking and Endometrial Cancer Risk: Observational and Mendelian Randomization Analyses

BACKGROUND

Current epidemiologic evidence indicates that smoking is associated with a lower endometrial cancer risk. However, it is unknown if this association is causal or confounded. To further elucidate the role of smoking in endometrial cancer risk, we conducted complementary observational and Mendelian randomization (MR) analyses.

METHODS

The observational analyses included 286,415 participants enrolled in the European Prospective Investigation into Cancer and Nutrition and 179,271 participants in the UK Biobank, and multivariable Cox proportional hazards models were used. In two-sample MR analyses, genetic variants robustly associated with lifetime amount of smoking (n = 126 variants) and ever having smoked regularly (n = 112 variants) were selected and their association with endometrial cancer risk (12,906 cancer/108,979 controls from the Endometrial Cancer Association Consortium) was examined.

RESULTS

In the observational analysis, lifetime amount of smoking and ever having smoked regularly were associated with a lower endometrial cancer risk. In the MR analysis accounting for body mass index, a genetic predisposition to a higher lifetime amount of smoking was not associated with endometrial cancer risk (OR per 1-SD increment: 1.15; 95% confidence interval: 0.91-1.44). Genetic predisposition to ever having smoked regularly was not associated with risk of endometrial cancer.

CONCLUSIONS

Smoking was inversely associated with endometrial cancer in the observational analyses, although unsupported by the MR. Additional studies are required to better understand the possible confounders and mechanisms underlying the observed associations between smoking and endometrial cancer.

IMPACT

The results from this analysis indicate that smoking is unlikely to be causally linked with endometrial cancer risk.

Insulin-Lowering Diets in Metastatic Cancer

Hyperinsulinemia is an independent risk factor for cancer mortality. Insulin-lowering dietary strategies such as calorie restriction (CR), low-carbohydrate or ketogenic diets (KD), and intermittent fasting (IF) are aimed at reducing systemic stores of nutrients utilized by cancer cells, attenuating insulin-related growth signaling, and improving obesity-related metabolic parameters. In this narrative review, we searched the published literature for studies that tested various insulin-lowering diets in metastatic cancer in preclinical and clinical settings. A total of 23 studies were identified. Of these, 14 were preclinical studies of dietary strategies that demonstrated improvements in insulin levels, inhibition of metastasis, and/or reduction in metastatic disease burden in animal models. The remaining nine clinical studies tested carbohydrate restriction, KD, or IF strategies which appear to be safe and feasible in patients with metastatic cancer. These approaches have also been shown to improve serum insulin and other metabolic parameters. Though promising, the anti-cancer efficacy of these interventions, such as impact on tumor response, disease-specific-, and overall survival, have not yet been conclusively demonstrated. Studies that are adequately powered to evaluate whether insulin-lowering diets improve cancer outcomes are warranted.

Metabolically Defined Body Size Phenotypes and Risk of Endometrial Cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)

BACKGROUND

Obesity is a risk factor for endometrial cancer but whether metabolic dysfunction is associated with endometrial cancer independent of body size is not known.

METHODS

The association of metabolically defined body size phenotypes with endometrial cancer risk was investigated in a nested case-control study (817 cases/ 817 controls) within the European Prospective Investigation into Cancer and Nutrition (EPIC). Concentrations of C-peptide were used to define metabolically healthy (MH; <1st tertile) and metabolically unhealthy (MU; ≥1st tertile) status among the control participants. These metabolic health definitions were combined with normal weight (NW); body mass index (BMI)<25 kg/m2 or waist circumference (WC)<80 cm or waist-to-hip ratio (WHR)<0.8) and overweight (OW; BMI≥25 kg/m2 or WC≥80 cm or WHR≥0.8) status, generating four phenotype groups for each anthropometric measure: (i) MH/NW, (ii) MH/OW, (iii) MU/NW, and (iv) MU/OW.

RESULTS

In a multivariable-adjusted conditional logistic regression model, compared with MH/NW individuals, endometrial cancer risk was higher among those classified as MU/NW [ORWC, 1.48; 95% confidence interval (CI), 1.05-2.10 and ORWHR, 1.68; 95% CI, 1.21-2.35] and MU/OW (ORBMI, 2.38; 95% CI, 1.73-3.27; ORWC, 2.69; 95% CI, 1.92-3.77 and ORWHR, 1.83; 95% CI, 1.32-2.54). MH/OW individuals were also at increased endometrial cancer risk compared with MH/NW individuals (ORWC, 1.94; 95% CI, 1.24-3.04).

CONCLUSIONS

Women with metabolic dysfunction appear to have higher risk of endometrial cancer regardless of their body size. However, OW status raises endometrial cancer risk even among women with lower insulin levels, suggesting that obesity-related pathways are relevant for the development of this cancer beyond insulin.

IMPACT

Classifying women by metabolic health may be of greater utility in identifying those at higher risk for endometrial cancer than anthropometry per se.

The Role of Microbiota in the Immunopathogenesis of Endometrial Cancer

The female reproductive tract hosts a specific microbiome, which plays a crucial role in sustaining equilibrium and good health. In the majority of reproductive women, the microbiota (all bacteria, viruses, fungi, and other single-celled organisms within the human body) of the vaginal and cervical microenvironment are dominated by Lactobacillus species, which benefit the host through symbiotic relationships, in comparison to the uterus, fallopian tubes, and ovaries, which may contain a low-biomass microbiome with a diverse mixture of microorganisms. Although disruption to the balance of the microbiota develops, the altered immune and metabolic signaling may cause an impact on diseases such as cancer. These pathophysiological modifications in the gut–uterus axis may spark gynecological cancers. New information displays that gynecological and gastrointestinal tract dysbiosis (disruption of the microbiota homeostasis) can play an active role in the advancement and metastasis of gynecological neoplasms, such as cervical, endometrial, and ovarian cancers. Understanding the relationship between microbiota and endometrial cancer is critical for prognosis, diagnosis, prevention, and the development of innovative treatments. Identifying a specific microbiome may become an effective method for characterization of the specific microbiota involved in endometrial carcinogenesis. The aim of this study was to summarize the current state of knowledge that describes the correlation of microbiota with endometrial cancer with regard to the formation of immunological pathologies.

Identifying molecular mediators of the relationship between body mass index and endometrial cancer risk: a Mendelian randomization analysis

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 using multivariable MR.

METHODS

Genetic instruments to proxy 14 molecular risk factors and BMI were constructed by identifying single-nucleotide polymorphisms (SNPs) reliably associated (P < 5.0 × 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.

RESULTS

In MR analyses, there was strong evidence that BMI (OR per standard deviation (SD) increase 1.88, 95% CI 1.69 to 2.09, P = 3.87 × 10-31), total testosterone (OR per inverse-normal transformed nmol/L increase 1.64, 95% CI 1.43 to 1.88, P = 1.71 × 10-12), bioavailable testosterone (OR per natural log transformed nmol/L increase: 1.46, 95% CI 1.29 to 1.65, P = 3.48 × 10-9), fasting insulin (OR per natural log transformed pmol/L increase: 3.93, 95% CI 2.29 to 6.74, P = 7.18 × 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 × 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 × 10-2) had an effect on endometrial cancer risk. In mediation analysis, we found evidence for a mediating role of fasting insulin (19% total effect mediated, 95% CI 5 to 34%, P = 9.17 × 10-3), bioavailable testosterone (15% mediated, 95% CI 10 to 20%, P = 1.43 × 10-8) and SHBG (7% mediated, 95% CI 1 to 12%, P = 1.81 × 10-2) in the relationship between BMI and endometrial cancer risk.

CONCLUSIONS

Our comprehensive MR analysis provides insight into potential causal mechanisms linking BMI with endometrial cancer risk and suggests targeting of insulinemic and hormonal traits as a potential strategy for the prevention of endometrial cancer.

Insulin and cancer: a tangled web

For a century, since the pioneering work of Otto Warburg, the interwoven relationship between metabolism and cancer has been appreciated. More recently, with obesity rates rising in the U.S. and worldwide, epidemiologic evidence has supported a link between obesity and cancer. A substantial body of work seeks to mechanistically unpack the association between obesity, altered metabolism, and cancer. Without question, these relationships are multifactorial and cannot be distilled to a single obesity- and metabolism-altering hormone, substrate, or factor. However, it is important to understand the hormone-specific associations between metabolism and cancer. Here, we review the links between obesity, metabolic dysregulation, insulin, and cancer, with an emphasis on current investigational metabolic adjuncts to standard-of-care cancer treatment.

Adiposity and breast, endometrial, and colorectal cancer risk in postmenopausal women: Quantification of the mediating effects of leptin, C-reactive protein, fasting insulin, and estradiol

BACKGROUND

Mechanisms underlying the adiposity-cancer relationship are incompletely understood. We quantified the mediating roles of C-reactive protein (CRP), leptin, fasting insulin, and estradiol in the effect of adiposity on estrogen receptor (ER)-positive breast, endometrial, and colorectal cancer risk in postmenopausal women.

METHODS

We used a case-cohort study within the Women's Health Initiative Observational Study, analyzed as a cumulative sampling case-control study. The study included 188 breast cancer cases, 98 endometrial cancer cases, 193 colorectal cancer cases, and 285 controls. Interventional indirect and direct effects on the risk ratio (RR) scale were estimated using causal mediation analysis.

RESULTS

For breast cancer, the total effect RR for BMI ≥30 versus ≥18.5-<25 kg/m2 was 1.87 (95%CI,1.11-3.13). The indirect effect RRs were 1.38 (0.79-2.33) through leptin and CRP, 1.58 (1.17-2.43) through insulin, and 1.11 (0.98-1.30) through estradiol. The direct effect RR was 0.82 (0.39-1.68). For endometrial cancer, the total effect RR was 2.12 (1.12-4.00). The indirect effect RRs were 1.72 (0.85-3.98) through leptin and CRP, 1.42 (0.96-2.26) through insulin, and 1.24 (1.03-1.65) through estradiol. The direct effect RR was 0.70 (0.23-2.04). For colorectal cancer, the total effect RR was 1.70 (1.03-2.79). The indirect effect RRs were 1.04 (0.61-1.72) through leptin and CRP, 1.36 (1.00-1.88) through insulin, and 1.02 (0.88-1.17) through estradiol. The direct effect RR was 1.16 (0.58-2.43).

CONCLUSION

Leptin, CRP, fasting insulin, and estradiol appear to mediate the effect of high BMI on cancer risk to different extents, with likely varying degrees of importance between cancers. These insights might be important in developing interventions to modify obesity-associated cancer risk in postmenopausal women.

Fasting Insulin and Risk of Overall and 14 Site-Specific Cancers: Evidence From Genetic Data

Objective

Whether fasting insulin (FI) plays a role in cancer risk remains unclear. This study aimed to investigate the association between FI and cancer risk and to explore its potential mediator role in the association between type 2 diabetes mellitus (T2DM) and cancer.

Methods

Two-sample Mendelian randomization (TSMR) analysis was performed to evaluate the effect of FI on overall and 14 site-specific cancers using genome-wide association study (GWAS) summary-level data from Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC) and consortia of 14 site-specific cancers. The primary MR approach was conducted by using the random-effect inverse-variance weighted (IVW) method, and sensitivity analyses were implemented by adopting weighted-median, weighted-mode, MR-Egger, and MR-PRESSO tests. Polygenic risk score analysis was executed by using individual-level data from UK Biobank to validate the findings from TSMR analyses. Multivariable Mendelian randomization (MVMR) was carried out to estimate the mediation effect of FI on the association between T2DM and cancer.

Results

TSMR study suggested that genetically determined high FI levels were associated with increased risk of colorectal cancer (odds ratio (OR) = 1.87, 95% CI: 1.23-2.84, p = 0.003) and endometrial cancer (OR = 1.89, 95% CI: 1.08-3.01, p = 0.008), but not associated with overall cancer risk or the other 12 studied cancer sites. Polygenic risk score analysis successfully replicated the association between genetic liability to high FI levels and the increased risk of colorectal and endometrial cancers. MVMR and MR mediation analyses detected an intermediary effect of FI and quantified that FI mediated 21.3% of the association between T2DM and endometrial cancer.

Conclusions

This study demonstrated that FI levels are associated with the risk of colorectal and endometrial cancers, and FI was found to play an intermediary role in the association between T2DM and endometrial cancer. The associations between FI and other cancers need to be further studied.

Insulin promotes hepatocarcinoma tumorigenesis by up-regulating PKM2 expression

Insulin, as a growth factor, can increase the risk of certain types of cancer. The present study showed that insulin promoted the proliferation of hepatocellular carcinoma cells in vitro and in vivo through pyruvate kinase M2 (PKM2), which is a rate-limiting enzyme in the process of glycolysis. Moreover, the expression of PKM2 was up-regulated by insulin at the posttranslational level in a nuclear orphan receptor TR3-dependent manner. In addition, insulin could enhance the interaction between PKM2 and TR3 and protect PKM2 from degradation. Our results identified a specific mechanism of insulin affecting cancer metabolism and thus promoting cancer progression, and they contribute to a better understanding of the observation that insulin is linked to an increased cancer risk under hyperinsulinemic conditions.

Fertility-Sparing Approach in Women Affected by Stage I and Low-Grade Endometrial Carcinoma: An Updated Overview

Endometrial cancer (EC) is a deleterious condition which strongly affects a woman's quality of life. Although aggressive interventions should be considered to treat high-grade EC, a conservative approach should be taken into consideration for women wishing to conceive. In this scenario, we present an overview about the EC fertility-sparing approach state of art. Type I EC at low stage is the only histological type which can be addressed with a fertility-sparing approach. Moreover, no myometrium and/or adnexal invasion should be seen, and lymph-vascular space should not be involved. Regarding the pharmaceutical target, progestins, in particular medroxyprogesterone acetate (MPA) or megestrol acetate (MA), are the most employed agent in conservative treatment of early-stage EC. The metformin usage and hysteroscopic assessment is still under debate, despite promising results. Particularly strict and imperious attention should be given to the follow-up and psychological wellbeing of women, especially because of the double detrimental impairment: both EC and EC-related infertility consequences.

Testosterone, sex hormone-binding globulin, insulin-like growth factor-1 and endometrial cancer risk: observational and Mendelian randomization analyses

BACKGROUND

Dysregulation of endocrine pathways related to steroid and growth hormones may modify endometrial cancer risk; however, prospective data on testosterone, sex hormone-binding globulin (SHBG) and insulin-like growth factor (IGF)-1 are limited. To elucidate the role of these hormones in endometrial cancer risk we conducted complementary observational and Mendelian randomization (MR) analyses.

METHODS

The observational analyses included 159,702 women (80% postmenopausal) enrolled in the UK Biobank. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models. For MR analyses, genetic variants associated with hormone levels were identified and their association with endometrial cancer (12,906 cases/108,979 controls) was examined using two-sample MR.

RESULTS

In the observational analysis, higher circulating concentrations of total (HR per unit inverse normal scale = 1.38, 95% CI = 1.22-1.57) and free testosterone (HR per unit log scale = 2.07, 95% CI = 1.66-2.58) were associated with higher endometrial cancer risk. An inverse association was found for SHBG (HR per unit inverse normal scale = 0.76, 95% CI = 0.67-0.86). Results for testosterone and SHBG were supported by the MR analyses. No association was found between genetically predicted IGF-1 concentration and endometrial cancer risk.

CONCLUSIONS

Our results support probable causal associations between circulating concentrations of testosterone and SHBG with endometrial cancer risk.

Prospective analysis of circulating metabolites and endometrial cancer risk

BACKGROUND

Endometrial cancer is strongly associated with obesity and dysregulation of metabolic factors such as estrogen and insulin signaling are causal risk factors for this malignancy. To identify additional novel metabolic pathways associated with endometrial cancer we performed metabolomic analyses on pre-diagnostic plasma samples from 853 case-control pairs from the European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

A total of 129 metabolites (acylcarnitines, amino acids, biogenic amines, glycerophospholipids, hexoses, and sphingolipids) were measured by liquid chromatography-mass spectrometry. Conditional logistic regression estimated the associations of metabolites with endometrial cancer risk. An analysis focusing on clusters of metabolites using the bootstrap lasso method was also employed.

RESULTS

After adjustment for body mass index, sphingomyelin [SM] C18:0 was positively (OR1SD: 1.18, 95% CI: 1.05-1.33), and glycine, serine, and free carnitine (C0) were inversely (OR1SD: 0.89, 95% CI: 0.80-0.99; OR1SD: 0.89, 95% CI: 0.79-1.00 and OR1SD: 0.91, 95% CI: 0.81-1.00, respectively) associated with endometrial cancer risk. Serine, C0 and two sphingomyelins were selected by the lasso method in >90% of the bootstrap samples. The ratio of esterified to free carnitine (OR1SD: 1.14, 95% CI: 1.02-1.28) and that of short chain to free acylcarnitines (OR1SD: 1.12, 95% CI: 1.00-1.25) were positively associated with endometrial cancer risk. Further adjustment for C-peptide or other endometrial cancer risk factors only minimally altered the results.

CONCLUSION

These findings suggest that variation in levels of glycine, serine, SM C18:0 and free carnitine may represent specific pathways linked to endometrial cancer development. If causal, these pathways may offer novel targets for endometrial cancer prevention.

Reproductive tract neoplasia in adult female Asian elephants (Elephas maximus)

Recent reports have highlighted a lower-than-expected prevalence of neoplasia in elephants and suggested mechanisms for cancer resistance. But despite infrequent reports in the literature, uterine neoplasia is common in managed Asian elephants (Elephas maximus). This study is an archival review of reproductive tract neoplasia in 80 adult female Asian elephant mortalities in managed care facilities in the United States from 1988 to 2019. Neoplasms occurred in 64/80 (80%) of cases. Most were in the uterus (63/64; 98%) with only a single case of ovarian neoplasia. Myometrial leiomyomas were present in 57/63 (90%) cases with uterine neoplasia. Uterine adenocarcinoma was present in 8/63 (13%) cases. Remaining cases included endometrial adenoma (2), focal carcinoma in situ in endometrial polyps (1), anaplastic carcinoma (1), endometrial hemangioma (1), primitive neuroectodermal tumor (PNET; 1), and angiosarcoma (1). One case with uterine adenocarcinoma had a separate pelvic mass histologically characterized as an anaplastic sarcoma. Distant metastases were documented in 5/8 (63%) cases of uterine adenocarcinoma, and in the uterine anaplastic carcinoma, PNET, and angiosarcoma. Four uterine adenocarcinomas and one carcinoma in situ were examined immunohistochemically for pan-cytokeratin, vimentin, and estrogen receptor. In all, neoplastic cells were pan-cytokeratin positive and vimentin negative, and in 2 cases were immunoreactive for estrogen receptor. Results show that female reproductive tract neoplasia, particularly of the uterus, is common in Asian elephants and is not limited to leiomyomas. Importantly, uterine neoplasms have the potential to impact fecundity and may represent obstacles to conservation in managed care.

Tuning Chromophore-Based LMOF Dimensionality to Enhance Detection Sensitivity for Fe3+ Ions

Herein, we report the synthesis of two new manganese-based luminescent metal-organic frameworks (LMOFs) [Mn_0.5(tipe)(1,4-ndc)] _n (1) and [Mn(tipe)(1,4-ndc) (H₂O)·(DMF)₂·(H₂O)₃] _n (2) [tipe = 1,1,2,2-tetrakis(4-(1H-imidazol-1-yl)phenyl)ethene (tipe) and 1,4-ndc = 1,4-naphthalenedicarboxylic acid] constructed from an aggregation-induced emission (AIE) chromophore ligand. Compound 1 can undergo a facile single-crystal-to-single-crystal transformation to form compound 2, which results in an increase in dimensionality from a two-dimensional (2D) network to a three-dimensional (3D) network. Both compounds demonstrate excellent performance for the solution-phase detection of Fe³⁺ ions through a significant and rapid quench in luminescence emission. Fluorescence titration experiments reveal that compound 2 is more selective toward Fe³⁺ compared to compound 1 because of its 3D stacking mode. The K _sv value for compound 2 (32 378 M^-1) is twice as large as that for compound 1 (15 854 M^-1) for the detection of Fe³⁺ ions. We attribute this significant increase in performance to the increase in dimensionality. In addition, compound 2 demonstrates high selectivity and sensitivity for the detection of Cr³⁺ cations and Cr₂O₇ ^2- anions.

Gender Differences in Obesity-Related Cancers

PURPOSE OF REVIEW

In this review, we summarize the role of obesity in carcinogenesis, providing details on specific cancer sites. Special emphasis is given to gender differences in obesity-related cancers and on the effect of bariatric surgery on cancer risk.

RECENT FINDINGS

Accumulating evidence has highlighted the detrimental role of overweight/obesity in cancer, with almost 55% of cancers diagnosed in women and 24% diagnosed in men considered overweight- and obesity-related cancers. Sufficient data have shown that higher BMI is associated with risk of gynecologic malignancies (mainly breast and endometrial cancers) as well as cancers in sites such as the esophagus (adenocarcinoma), gastric cardia, colon, rectum, liver, gallbladder, pancreas, kidney, thyroid gland, and multiple myeloma. The main mechanisms underlying this relationship include the insulin/IGF1 system, the effect of sex hormones, and adipocytokines. Marked differences may be seen in specific cancer sites when comparing men to women. There is a higher overall incidence of obesity-related cancers among females (endometrial, ovarian, and postmenopausal female breast cancers), whereas cancers that concern both sexes show a higher incidence in males, particularly esophageal adenocarcinoma (male to female ratio: 9: 1 in the USA). Additionally, bariatric surgery has provided evidence of lowering overall cancer risk in patients with morbid obesity. Interestingly, bariatric surgery may lower overall cancer risk in women within the first 5 years after surgery due to the reduced risk of breast and endometrial cancer, and non-Hodgkin lymphoma. Obesity constitutes the base for marked metabolic, hormonal, and inflammatory alterations, including increased cancer risk in both men and women. Implementation of early obesity prevention strategies could ameliorate the continuously increasing incidence of cancer attributed to obesity.

Glycemic Index, Glycemic Load, and Risk of Ovarian Cancer in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cohort

BACKGROUND

Ovarian cancer is the fifth most common cause of cancer death among women in the US, yet few modifiable risk factors have been established. Diets high in glycemic index (GI) and glycemic load (GL) have been linked to several cancers, but epidemiologic studies of ovarian cancer have yielded inconsistent results.

OBJECTIVE

In this study, we aimed to examine associations between GI or GL and ovarian cancer.

METHODS

We used prospective data from the Prostate, Lung, Colorectal, and Ovarian cohort. GI and GL were calculated from validated FFQs. Participants were women who were aged 60 to 74 y, did not have a history of cancer, and had both ovaries. Cox proportional hazard models were used to calculate HRs and 95% CIs for risk of ovarian cancer associated with quartiles of GI and GL. Analyses were performed separately for those who completed the dietary questionnaire at baseline (DQX) or later in the study (DHQ).

RESULTS

From the DQX sample set, 181 cases were identified among 24,633 women with median follow-up of 12.1 y; there were 211 cases among 42,410 women in the DHQ set, with median follow-up of 8.9 y. After adjusting for age at dietary questionnaire completion, year of randomization, year of questionnaire, study center, and oral contraceptive use, the risk of ovarian cancer decreased by 43% (HR: 0.57; 95% CI: 0.37, 0.88) among those in the highest compared with those in the lowest quartile of GL (DQX). Those in the highest compared with those in the lowest quartile of GI (DHQ), had a 38% lower risk (HR: 0.62; 95% CI: 0.42, 1.00).

CONCLUSIONS

We observed lower risk of ovarian cancer associated with higher GI and GL. Results should be interpreted with caution as they may have been influenced by limitations including lack of variability in dietary intake. Additional studies are needed to better understand what is driving these associations.

The Potential Health Benefits of the Ketogenic Diet: A Narrative Review

Considering the lack of a comprehensive, multi-faceted overview of the ketogenic diet (KD) in relation to health issues, we compiled the evidence related to the use of the ketogenic diet in relation to its impact on the microbiome, the epigenome, diabetes, weight loss, cardiovascular health, and cancer. The KD diet could potentially increase genetic diversity of the microbiome and increase the ratio of Bacteroidetes to Firmicutes. The epigenome might be positively affected by the KD since it creates a signaling molecule known as β-hydroxybutyrate (BHB). KD has helped patients with diabetes reduce their HbA1c and reduce the need for insulin. There is evidence to suggest that a KD can help with weight loss, visceral adiposity, and appetite control. The evidence also suggests that eating a high-fat diet improves lipid profiles by lowering low-density lipoprotein (LDL), increasing high-density lipoprotein (HDL), and lowering triglycerides (TG). Due to the Warburg effect, the KD is used as an adjuvant treatment to starve cancer cells, making them more vulnerable to chemotherapy and radiation. The potential positive impacts of a KD on each of these areas warrant further analysis, improved studies, and well-designed randomized controlled trials to further illuminate the therapeutic possibilities provided by this dietary intervention.

YTHDF2 inhibit the tumorigenicity of endometrial cancer via downregulating the expression of IRS1 methylated with m6A

RNA epigenetic modification take part in many biology processes, and the N6-methyladenosine (m⁶A) methylation of specific mRNAs in endometrial cancer (EC) tissues play a key role in regulating the tumorigenicity of EC, but the specific mechanism still unknown and need to be investigated in the future. Here, we found that m⁶A reader protein YTHDF2 expression was significantly upregulated in EC compare to tumor adjacent tissues, YTHDF2 was then identified to inhibit the proliferation and invasion of EC cell lines. Mechanistically, the m⁶A reader YTHDF2 bind the methylation sites of target transcripts IRS1 and promoted IRS1 mRNA degradation, consequently inhibiting the expression of IRS1 and inhibiting IRS1/AKT signaling pathway, finally inhibit the tumorigenicity of EC. Thus, we demonstrated that YTHDF2 inhibited the proliferation and invasion of EC via inhibiting IRS1 expression in m⁶A epigenetic way, which suggests a potential therapeutic target for EC.

Hyperinsulinemia in Obesity, Inflammation, and Cancer

The relative insufficiency of insulin secretion and/or insulin action causes diabetes. However, obesity and type 2 diabetes mellitus can be associated with an absolute increase in circulating insulin, a state known as hyperinsulinemia. Studies are beginning to elucidate the cause-effect relationships between hyperinsulinemia and numerous consequences of metabolic dysfunctions. Here, we review recent evidence demonstrating that hyperinsulinemia may play a role in inflammation, aging and development of cancers. In this review, we will focus on the consequences and mechanisms of excess insulin production and action, placing recent findings that have challenged dogma in the context of the existing body of literature. Where relevant, we elaborate on the role of specific signal transduction components in the actions of insulin and consequences of chronic hyperinsulinemia. By discussing the involvement of hyperinsulinemia in various metabolic and other chronic diseases, we may identify more effective therapeutics or lifestyle interventions for preventing or treating obesity, diabetes and cancer. We also seek to identify pertinent questions that are ripe for future investigation.

Diabetes and Cancer: Metabolic Association, Therapeutic Challenges, and the Role of Natural Products

Cancer is considered the second leading cause of death worldwide and in 2018 it was responsible for approximately 9.6 million deaths. Globally, about one in six deaths are caused by cancer. A strong correlation was found between diabetes mellitus and carcinogenesis with the most evident correlation was with type 2 diabetes mellitus (T2DM). Research has proven that elevated blood glucose levels take part in cell proliferation and cancer cell progression. However, limited studies were conducted to evaluate the efficiency of conventional therapies in diabetic cancer patients. In this review, the correlation between cancer and diabetes will be discussed and the mechanisms by which the two diseases interact with each other, as well as the therapeutics challenges in treating patients with diabetes and cancer with possible solutions to overcome these challenges. Natural products targeting both diseases were discussed with detailed mechanisms of action. This review will provide a solid base for researchers and physicians to test natural products as adjuvant alternative therapies to treat cancer in diabetic patients.

Sex Hormones, Insulin, and Insulin-like Growth Factors in Recurrence of High-Stage Endometrial Cancer

BACKGROUND

The influence of sex hormone and insulin/insulin-like growth factor (IGF) axis signaling on endometrial cancer recurrence is unknown. We evaluated these pathways in a prospective cohort of Gynecologic Oncology Group (GOG)0210 trial endometrial adenocarcinoma patients.

METHODS

Stage II-IV patients (N = 816) were included in this study. Pretreatment specimens were tested for tumor mRNA and protein expression of IGF1, IGF2, IGF-binding proteins (IGFBP)-1 and -3, insulin (IR) and IGF-I receptors (IGF1R), phosphorylated IR/IGF1R (pIGF1R/pIR), and estrogen (ER) and progesterone receptors (PR) using qPCR and IHC. Serum concentrations of insulin, IGF-I, IGFBP-3, estradiol, estrone, and sex hormone binding globulin were measured. HRs and 95% confidence intervals (CI) for progression-free survival were calculated from Cox models adjusting for age, stage, and grade.

RESULTS

Recurrence occurred in 280 (34%) cases during a median of 4.6 years of follow-up. ER positivity (HR, 0.67; 95% CI, 0.47-0.95), IR positivity (HR, 0.53; 95% CI, 0.29-0.98), and circulating IGF-I (highest vs. lowest quartile: HR, 0.66; 95% CI, 0.47-0.92) were inversely associated with recurrence risk. Circulating estradiol (highest vs. lowest tertile: HR, 1.55; 95% CI, 1.02-2.36) and pIGF1R/pIR positivity (HR, 1.40; 95% CI, 1.02-1.92) were associated with increased recurrence risk.

CONCLUSIONS

Circulating estradiol and tumor tissue phosphorylated (activated) IGR1R/IR were independently associated with higher risk of recurrence in patients with endometrial cancer.

IMPACT

This study may inform future clinical trials of endocrine-targeted adjuvant therapies in patients with endometrial cancer that could include baseline assessment of serum and tissue biomarkers of estradiol and insulin signaling pathways.

Racial/ethnic differences in anthropometric and hormone-related factors and endometrial cancer risk: the Multiethnic Cohort Study

BACKGROUND

Anthropometric and hormone-related factors are established endometrial cancer risk factors; however, little is known about the impact of these factors on endometrial cancer risk in non-White women.

METHODS

Among 110,712 women participating in the Multiethnic Cohort (MEC) Study, 1150 incident invasive endometrial cancers were diagnosed. Hazard ratios (HRs) and 95% confidence intervals (CIs) for associations with endometrial cancer risk for race/ethnicity and for risk factors across racial/ethnic groups were calculated.

RESULTS

Having a higher body mass index (BMI) at baseline or age 21 years was strongly associated with increased risk (p_int race/ethnicity ≥ 0.36). Parity (vs nulliparity) was inversely associated with risk in all the groups except African Americans (p_int 0.006). Current use of postmenopausal hormones at baseline (PMH-E; vs never use) was associated with increased risk in Whites and Japanese Americans (p_int 0.002). Relative to Whites, endometrial cancer risk was lower in Japanese Americans and Latinas and non-significantly higher in Native Hawaiians. Risk in African Americans did not differ from that in Whites.

CONCLUSIONS

Racial/ethnic differences in endometrial cancer risk were not fully explained by anthropometric or hormone-related risk factors. Further studies are needed to identify reasons for the observed racial/ethnic differences in endometrial cancer risk.

The Influence of Biologically Active Substances Secreted by the Adipose Tissue on Endometrial Cancer

Endometrial cancer is one of the most frequently diagnosed gynecological neoplasms in developed countries and its incidence is rising. Usually, it is diagnosed in the early stages of the disease and has a good prognosis; however, in later stages, the rate of recurrence reaches up to 60%. The discrepancy in relapse rates is due to the heterogeneity of the group related to the presence of prognostic factors affecting survival parameters. Increased body weight, diabetes, metabolic disturbances and estrogen imbalance are important factors for the pathogenesis of endometrial cancer. Even though prognostic factors such as histopathological grade, clinical stage, histological type and the presence of estrogen and progesterone receptors are well known in endometrial cancer, the search for novel prognostic biomarkers continues. Adipose tissue is an endocrine organ involved in metabolism, immune response and the production of biologically active substances participating in cell growth and differentiation, angiogenesis, apoptosis and carcinogenesis. In this manuscript, we review the impact of factors secreted by the adipose tissue involved in the regulation of glucose and lipid metabolism (leptin, adiponectin, omentin, vaspin, galectins) and factors responsible for homeostasis maintenance, inflammatory processes, angiogenesis and oxidative stress (IL-1β, 6, 8, TNFα, Vascular endothelial growth factor (VEGF), Fibroblast growth factors (FGFs)) in the diagnosis and prognosis of endometrial cancer.

Diabetes, Obesity, and Inflammation: Impact on Clinical and Radiographic Features of Breast Cancer

Obesity, diabetes, and inflammation increase the risk of breast cancer, the most common malignancy in women. One of the mainstays of breast cancer treatment and improving outcomes is early detection through imaging-based screening. There may be a role for individualized imaging strategies for patients with certain co-morbidities. Herein, we review the literature regarding the accuracy of conventional imaging modalities in obese and diabetic women, the potential role of anti-inflammatory agents to improve detection, and the novel molecular imaging techniques that may have a role for breast cancer screening in these patients. We demonstrate that with conventional imaging modalities, increased sensitivity often comes with a loss of specificity, resulting in unnecessary biopsies and overtreatment. Obese women have body size limitations that impair image quality, and diabetes increases the risk for dense breast tis-sue. Increased density is known to obscure the diagnosis of cancer on routine screening mammography. Novel molecu-lar imaging agents with targets such as estrogen receptor, human epidermal growth factor receptor 2 (HER2), pyrimi-dine analogues, and ligand-targeted receptor probes, among others, have potential to reduce false positive results. They can also improve detection rates with increased resolution and inform therapeutic decision making. These emerg-ing imaging techniques promise to improve breast cancer diagnosis in obese patients with diabetes who have dense breasts, but more work is needed to validate their clinical application.

Differential Expressions of Ki-67, Bcl-2, and Apoptosis Index in Endometrial Cells of Women With and Without Type II Diabetes Mellitus and Their Correlation with Clinicopathological Variables

The objective of this study was to investigate proliferation, apoptosis, and antiapoptotic molecule expression in endometrial cells of reproductive-aged women with and without type II diabetes mellitus (T2D). In this case-control study, a total of 80 endometrial tissue specimens from reproductive-aged women (35 in the proliferative phase and 45 in the secretory phase) were examined. The age and body mass index (BMI) were matched between the groups. Formalin-fixed and paraffin-embedded endometrial tissue samples were used for immunohistochemistry analysis. The presence of proliferation was evaluated with Ki-67 expression, antiapoptotic function of cells was evaluated with Bcl-2 expression, and apoptosis was evaluated with terminal deoxynucleotidyl transferase (TUNEL) immunoreactivity in both the glandular epithelium and stroma of endometrial tissue samples from women with and without T2D. Ki-67 expression in the glandular epithelium and Bcl-2 expression in both the glandular epithelium and stroma were significantly higher in endometrial tissue samples of women in the T2D group than the control group (p = 0.0008, p = 0.0022, and p = 0.0261, respectively). TUNEL immunoreactivity was significantly lower in the glandular epithelium of women in the T2D group than the control group (p = 0.0001). Glandular Ki-67 expression correlated positively with BMI, use of insulin, and hemoglobin A1c level (p = 0.0034, p = 0.0154, and p = 0.0011, respectively). Glandular Bcl-2 expression correlated positively with BMI and duration of T2D (p = 0.0090 and p = 0.0109, respectively). Stromal Bcl-2 expression correlated positively with duration of T2D (p = 0.0069). TUNEL immunoreactivity in the glandular epithelium correlated negatively with duration of T2D (p = 0.0340) and positively with the use of oral antidiabetic agents (p = 0.0226). Compared to age and BMI-matched controls, women with T2D experienced increased cell proliferation and decreased apoptosis in the glandular epithelium and increased antiapoptotic function in both the glandular epithelium and stromal cells. High BMI values in women with diabetes seemed to contribute to increased cell proliferation and increased antiapoptotic function in the glandular epithelium but not the stromal cells.

Adiposity and Endometrial Cancer Risk in Postmenopausal Women: A Sequential Causal Mediation Analysis

BACKGROUND

Adiposity increases endometrial cancer risk, possibly through inflammation, hyperinsulinemia, and increasing estrogens. We aimed to quantify the mediating effects of adiponectin (anti-inflammatory adipocytokine); IL6, IL1-receptor antagonist, TNF receptor 1 and 2, and C-reactive protein (inflammatory status biomarkers); C-peptide (hyperinsulinemia biomarker); and free estradiol and estrone (estrogen biomarkers) in the adiposity-endometrial cancer link in postmenopausal women.

METHODS

We used data from a case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC). Eligible women did not have cancer, hysterectomy, and diabetes; did not use oral contraceptives or hormone therapy; and were postmenopausal at recruitment. Mediating pathways from adiposity to endometrial cancer were investigated by estimating natural indirect (NIE) and direct (NDE) effects using sequential mediation analysis.

RESULTS

The study included 163 cases and 306 controls. The adjusted OR for endometrial cancer for body mass index (BMI) ≥30 versus ≥18.5-<25 kg/m2 was 2.51 (95% confidence interval, 1.26-5.02). The ORsNIE were 1.95 (1.01-3.74) through all biomarkers [72% proportion mediated (PM)] decomposed as: 1.35 (1.06-1.73) through pathways originating with adiponectin (33% PM); 1.13 (0.71-1.80) through inflammation beyond (the potential influence of) adiponectin (13% PM); 1.05 (0.88-1.24) through C-peptide beyond adiponectin and inflammation (5% PM); and 1.22 (0.89-1.67) through estrogens beyond preceding biomarkers (21% PM). The ORNDE not through biomarkers was 1.29 (0.54-3.09). Waist circumference gave similar results.

CONCLUSIONS

Reduced adiponectin and increased inflammatory biomarkers, C-peptide, and estrogens mediated approximately 70% of increased odds of endometrial cancer in women with obesity versus normal weight.

IMPACT

If replicated, these results could have implications for identifying targets for intervention to reduce endometrial cancer risk in women with obesity.

Obesity Epidemic-The Underestimated Risk of Endometrial Cancer

Endometrial cancer (EC) is the most frequently observed malignant gynecologic disease in developed countries. There is a strong association between the established risk factor obesity and the incidence of EC. Furthermore, the rate of women with a body mass index (BMI) > 30 kg/m2 is increasing worldwide, correspondingly leading to a higher prevalence of EC. Understanding the adipose tissue as an endocrine organ, elementary pathophysiological pathways of tumorigenesis have been revealed. This includes the fundamental role of hyperglycemia, insulin resistance, and hyperestrogenemia, as well as interactions with a chronic proinflammatory microenvironment. Therapeutic options potentially include metformin or bariatric surgery. Moreover, changes in individual lifestyle such as weight reduction, physical activity, and an awareness of healthy nutrition are effective in preventing the disease.

Oral contraceptive use by formulation and endometrial cancer risk among women born in 1947-1964: The Nurses' Health Study II, a prospective cohort study

Oral contraceptives (OCs) have been associated with long-term lower endometrial cancer risk; relatively little is known about associations with more recent OC formulations and associations with longer-term risk. A total of 107,069 women from the Nurses’ Health Study II recalled OC use from age 13 to baseline (1989); biennial questionnaires updated data on OC use until 2009. OCs were classified by estrogen and progestin type, dose, and potency based on reported brand. 864 incident endometrial cancer cases were identified through 2017. Multivariable Cox proportional hazards models estimated hazard ratios (HR) and 95% confidence intervals [95% CI] for the association of OC use with endometrial cancer risk. OC use was associated with lower endometrial cancer risk (ever use, HR 0.77 [95% CI 0.65–0.91]; >10 years of use, 0.43 [0.32–0.58] vs. never OC use). Inverse associations for duration were evident regardless of time since last use. Longer durations (> 5 years) of ethinyl estradiol (0.52 [0.41–0.67]) and second-generation progestins (0.43 [0.30–0.61]), both versus never use, were more strongly associated with lower risk than mestranol (0.66 [0.50–0.88], p-het = 0.01) and first-generation progestins (0.62 [0.49–0.78], p-het = 0.03). Inverse associations were generally observed for cross-classified cumulative average estrogen and progestin dose and potency (< vs. ≥ median; ever use vs. never OC use), with the exception of high estrogen and low progestin dose. OCs were associated with lower endometrial cancer risk, independent of time since last use. Use of ethinyl estradiol and second-generation progestins were more strongly inversely associated with risk compared with older formulations.

Circulating Insulin-like Growth Factor-I Concentrations and Risk of 30 Cancers: Prospective Analyses in UK Biobank

Circulating insulin-like growth factor I (IGF-I) is positively associated with the risks of colorectal, breast, and prostate cancer, but evidence for other less common cancers is limited. In this study, we investigated associations between serum IGF-I concentrations and incidence of less common cancers in the UK Biobank study. To enable comparison of effect estimates, and as positive controls, both common and less common cancer sites (total 30) were included in an outcome-wide analysis. Data from 394,388 cancer-free participants in the UK Biobank study were analyzed. Multivariable adjusted Cox proportional hazards models were used to determine associations between baseline serum IGF-I concentrations and cancer incidence, using repeated IGF-I measurements from up to 14,149 participants to correct for regression dilution bias. Higher IGF-I concentration was associated with increased risks of thyroid cancer [HR per 5 nmol/L higher concentration 1.18; 95% confidence interval (CI), 1.01-1.37] in addition to colorectal (HR, 1.08; 95% CI, 1.03-1.13), breast (HR, 1.11; 95% CI, 1.07-1.15), and prostate cancer (HR, 1.08; 95% CI, 1.05-1.12), and reduced risks of ovarian and liver cancer. Mean follow-up was 6.9 years and the possibility that the observed associations may be influenced by reverse causality bias cannot be excluded. Additional nominally significant associations with malignant melanoma, multiple myeloma, oral cancer, and esophageal squamous cell carcinoma did not survive correction for multiple testing. Studies with longer follow-up and pooled analyses are needed to further assess how broad the role of IGF-I is in cancer development. SIGNIFICANCE: The results from this outcome-wide analysis are consistent with a positive association of IGF-I with cancers at several sites.

Adherence to Cancer Prevention Guidelines and Endometrial Cancer Risk: Evidence from a Systematic Review and Dose-Response Meta-analysis of Prospective Studies

Purpose

The evidence of adherence to cancer prevention guidelines and endometrial cancer (EC) risk has been limited and controversial. This study summarizes and quantifies the relationship between adherence to cancer prevention guidelines and EC risk.

Materials and Methods

The online databases PubMed, Web of Science, and EMBASE were searched for relevant publications up to June 2, 2020. This study had been registered at PROSPERO. The registration number is CRD42020149966. Study quality evaluation was performed based on the Newcastle-Ottawa Scale. The I² statistic was used to estimate heterogeneity among studies. Egger’s and Begg’s tests assessed potential publication bias. Summary hazard ratios (HRs) and 95% confidence intervals (CIs) for the relationship between adherence to cancer prevention guidelines score was assigned to participants by summarizing individual scores for each lifestyle-related factor. The scores ranged from least healthy (0) to most healthy (20) and the EC risk was calculated using a random-effects model.

Results

Five prospective studies (four cohort studies and one case-cohort study) consisted of 4,470 EC cases, where 597,047 participants were included. Four studies had a low bias risk and one study had a high bias risk. Summary EC HR for the highest vs. lowest score of adherence to cancer prevention guidelines was 0.54 (95% CI, 0.40 to 0.73) and had a high heterogeneity (I²=86.1%). For the dose-response analysis, an increment of 1 significantly reduced the risk of EC by 6%. No significant publication bias was detected.

Conclusion

This study suggested that adherence to cancer prevention guidelines was negatively related to EC risk.

Is insulin resistance a predictor for complete response in breast cancer patients who underwent neoadjuvant treatment?

PURPOSE

Neoadjuvant chemotherapy is the standard front-line treatment modality in locally advanced breast cancer. Achieving pathological complete response (pCR) is a significant prognostic factor for prolonged disease-free and overall survival. Insulin resistance is defined as a pathological condition in which insulin effect is impaired in peripheral target tissues such as the skeletal muscle, liver, and adipose tissue. The relationship between breast cancer and insulin resistance is controversial. In this study, our aim is to evaluate the role of insulin resistance, body mass index (BMI), metabolic syndrome, and inflammation markers to predict complete response in breast cancer patients who underwent neoadjuvant treatment.

METHODS

Data from 55 locally advanced non-diabetic breast cancer patients, treated with neoadjuvant chemotherapy between 2015 and 2017, were retrospectively evaluated. Homeostatic model assessment, IR = insulin resistance (HOMA-IR) was calculated by using the obtained insulin and fasting blood glucose values before neoadjuvant chemotherapy (fasting insulin × fasting glucose/405). We considered a cut-off of 2.5 for insulin resistance. The systemic inflammatory index (SII), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) were calculated.

RESULTS

Twenty-five patients had no insulin resistance. The most common pathologic subtype (56%) was hormone receptor (HR) positive and human epidermal growth factor receptor-2 (Her-2)-negative invasive ductal carcinoma. Sixteen (29%) patients had a pathological complete response (pCR). We found that the probability of pCR in patients with insulin resistance was 4.7 times lower than that in patients without insulin resistance [OR: 4.7 (95%CI 1.7-17.2), p = 0.01].

CONCLUSION

Our results revealed that insulin resistance may have a negative effect on pathological complete response (pCR) following neoadjuvant therapy particularly with hormone-positive and Her-2-negative cases of non-diabetic breast cancer.

Insulin Resistance and Endometrial Cancer: Emerging Role for microRNA

Endometrial cancer (EC) remains one of the most common cancers of the female reproductive system. Epidemiological and clinical data implicate insulin resistance (IR) and its accompanying hyperinsulinemia as key factors in the development of EC. MicroRNAs (miRNAs) are short molecules of non-coding endogenous RNA that function as post-transcriptional regulators. Accumulating evidence has shown that the miRNA expression pattern is also likely to be associated with EC risk factors. The aim of this work was the verification of the relationships between IR, EC, and miRNA, and, as based on the literature data, elucidation of miRNA's potential utility for EC prevention in IR patients. The pathways affected in IR relate to the insulin receptors, insulin-like growth factors and their receptors, insulin-like growth factor binding proteins, sex hormone-binding globulin, and estrogens. Herein, we present and discuss arguments for miRNAs as a plausible molecular link between IR and EC development. Specifically, our careful literature search indicated that dysregulation of at least 13 miRNAs has been ascribed to both conditions. We conclude that there is a reasonable possibility for miRNAs to become a predictive factor of future EC in IR patients.

Using genetics to decipher the link between type 2 diabetes and cancer: shared aetiology or downstream consequence?

Recent developments in the field of genetics have accelerated our understanding of the aetiology of complex diseases. Type 2 diabetes mellitus and cancer are no exception, with large-scale genome-wide association studies (GWAS) facilitating exploration of the underlying pathology. Here, we discuss how genetics studies can be used to investigate the relationship between these complex diseases. Observational epidemiological studies consistently report that people with type 2 diabetes have a higher risk of several types of cancer. Indeed, type 2 diabetes and cancer share many common risk factors, such as obesity, ageing, poor diet and low levels of physical activity. However, questions remain regarding the biological mechanisms that link these two diseases. Large-scale GWAS of type 2 diabetes and cancer allow us to consider the evidence for shared genetic architecture. Several shared susceptibility genes have been identified, yet tissue specificity and direction of effect must be taken into account when considering common genetic aetiology. We also consider how GWAS, and associated techniques such as Mendelian randomisation, allow us to dissect the link between the two diseases and address questions such as 'Does type 2 diabetes cause cancer or is the increased risk observed driven by higher adiposity or another associated metabolic feature?' Graphical abstract.

Therapeutic effect of metformin in the treatment of endometrial cancer

The present review aims at reviewing the role of metformin in the treatment of endometrial cancer (EC). According to the literature, excessive estrogen levels and insulin resistance are established risk factors of EC. As a traditional insulin sensitizer and newly discovered anticancer agent, metformin directly and indirectly inhibits the development of EC. The direct mechanisms of metformin include inhibition of the LKB1-AMP-activated protein kinase-mTOR, PI3K-Akt and insulin-like growth factor 1-related signaling pathways, which reduces the proliferation and promotes the apoptosis of EC cells. In the indirect mechanism, metformin increases the insulin sensitivity of body tissues and decreases circulating insulin levels. Decreased levels of insulin increase the blood levels of sex hormone binding globulin, which leads to reductions in circulating estrogen and androgens. The aforementioned findings suggest that metformin serves an important role in the treatment of EC. Increased understanding of the mechanism of metformin in EC may provide novel insights into the treatment of this malignancy.

Endometrial Cancer as a Metabolic Disease with Dysregulated PI3K Signaling: Shedding Light on Novel Therapeutic Strategies

Endometrial cancer (EC) is one of the most common malignancies of the female reproductive organs. The most characteristic feature of EC is the frequent association with metabolic disorders. However, the components of these disorders that are involved in carcinogenesis remain unclear. Accumulating epidemiological studies have clearly revealed that hyperinsulinemia, which accompanies these disorders, plays central roles in the development of EC via the insulin-phosphoinositide 3 kinase (PI3K) signaling pathway as a metabolic driver. Recent comprehensive genomic analyses showed that over 90% of ECs have genomic alterations in this pathway, resulting in enhanced insulin signaling and production of optimal tumor microenvironments (TMEs). Targeting PI3K signaling is therefore an attractive treatment strategy. Several clinical trials for recurrent or advanced ECs have been attempted using PI3K-serine/threonine kinase (AKT) inhibitors. However, these agents exhibited far lower efficacy than expected, possibly due to activation of alternative pathways that compensate for the PIK3-AKT pathway and allow tumor growth, or due to adaptive mechanisms including the insulin feedback pathway that limits the efficacy of agents. Overcoming these responses with careful management of insulin levels is key to successful treatment. Further interest in specific TMEs via the insulin PI3K-pathway in obese women will provide insight into not only novel therapeutic strategies but also preventive strategies against EC.

Relationship between prediagnostic body mass index trajectory and colorectal adenomas: an analysis of the PLCO cancer screening trial

Background

Studies on the relationship between lifetime body mass index (BMI) trajectory and colorectal premalignant precursor lesions are limited. This study aimed to assess the relationship between prediagnostic adulthood BMI trajectory and the risk of colorectal adenomas using data from the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial.

Methods

In total, 39,824 participants in the intervention arm of the prospective PLCO cohort, who have undergone at least one colonoscopy or sigmoidoscopy examination with a confirmed diagnosis of colorectal adenomas, were enrolled and divided into four groups (underweight, normal weight, overweight, and obese) according to BMI during each age period. SAS Proc Traj was used to establish the BMI trajectory model. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

Compared with normal weight, overweight or obesity significantly increased colorectal adenomas risk in each age period after 30 years. Specifically, obesity in the 50s was most closely related to colorectal adenomas risk [HR: 1.32, 95% CI: (1.22, 1.43)]. BMI gain from the age of 40 to 50 [HR: 1.25, 95% CI: (1.11, 1.42)] showed the strongest correlation with an increased incidence of colorectal adenomas, followed by that from the age of 30 to 50 [HR: 1.19, 95% CI: (1.10, 1.29)], the age of 20 to 50 [HR: 1.16, 95% CI: (1.10, 1.24)], the age of 20 to 40 [HR: 1.14, 95% CI: (1.05, 1.23)], and the age of 20 to 30 [HR: 1.13, 95% CI: (1.02, 1.26)]. Additionally, compared with those who maintained normal weight throughout adulthood, those who progressed from normal weight to obesity [HR: 1.15, 95% CI: (1.06, 1.25)], or from overweight to obesity [HR: 1.33, 95% CI: (1.11, 1.61)], had a higher risk of colorectal adenomas.

Conclusions

Overweight and obesity increased the risk of colorectal adenomas, and this risk increased with advancing age.

ALKBH5 regulates IGF1R expression to promote the Proliferation and Tumorigenicity of Endometrial Cancer

N6-methyladenosine (m6A) messenger RNA methylation play important role in cell proliferation and tumorigenicity of endometrial cancer, but the key mechanism is not fully clear. Here, we found that RNA demethylase ALKBH5 expression was significantly upregulated in endometrial cancer, ALKBH5 was then identified to positively regulate proliferation and invasion of endometrial cancer. Mechanistically, the m6A eraser ALKBH5 demethylated target transcripts IGF1R and enhanced IGF1R mRNA stability, consequently promoting IGF1R translation and activating IGF1R signaling pathway. Thus, we demonstrated that ALKBH5 promoted proliferation and invasion of endometrial cancer via erasing IGF1R m6A-modifications, which suggests a potential therapeutic target for endometrial cancer.

The Impact of Hormonal Imbalances Associated with Obesity on the Incidence of Endometrial Cancer in Postmenopausal Women

Obesity has long been associated with endometrial cancer amongst postmenopausal women; in fact, obese women are more than twice as likely to develop endometrial cancer as women of normal weight. The risk of developing this type of cancer increases with weight gains in adulthood, especially among women who did not use hormonal therapy for menopause. Thus, with an association between menopause, obesity, and endometrial cancer established, it prompts the following question: what specific factors could cause higher risk levels for endometrial cancer in this cohort of women? In this paper, the factor of hormonal changes and imbalances associated with both obesity and menopause will be examined. The hormones that will be discussed are insulin and insulin-like factors, estrogen, and adipokines (specifically adiponectin, visfatin, and leptin).

Is Type 2 Diabetes Causally Associated With Cancer Risk? Evidence From a Two-Sample Mendelian Randomization Study

We conducted a two-sample Mendelian randomization study to investigate the causal associations of type 2 diabetes mellitus (T2DM) with risk of overall cancer and 22 site-specific cancers. Summary-level data for cancer were extracted from the Breast Cancer Association Consortium and UK Biobank. Genetic predisposition to T2DM was associated with higher odds of pancreatic, kidney, uterine, and cervical cancer and lower odds of esophageal cancer and melanoma but not associated with 16 other site-specific cancers or overall cancer. The odds ratios (ORs) were 1.13 (95% CI 1.04, 1.22), 1.08 (1.00, 1.17), 1.08 (1.01, 1.15), 1.07 (1.01, 1.15), 0.89 (0.81, 0.98), and 0.93 (0.89, 0.97) for pancreatic, kidney, uterine, cervical, and esophageal cancer and melanoma, respectively. The association between T2DM and pancreatic cancer was also observed in a meta-analysis of this and a previous Mendelian randomization study (OR 1.08; 95% CI 1.02, 1.14; P = 0.009). There was limited evidence supporting causal associations between fasting glucose and cancer. Genetically predicted fasting insulin levels were positively associated with cancers of the uterus, kidney, pancreas, and lung. The current study found causal detrimental effects of T2DM on several cancers. We suggest reinforcing the cancer screening in T2DM patients to enable the early detection of cancer.