The Role of Metabolic Syndrome in Endometrial Cancer: A Review

Classification Systems of Endometrial Cancer: A Comparative Study about Old and New

Endometrial cancer is the most common gynecological malignancy of the female reproductive organs. Historically it was divided into type I and type II, until 2013 when the Cancer Genome Atlas molecular classification was proposed. Here, we applied the different classification types on our endometrial cancer patient cohort in order to identify the most predictive one. We enrolled 117 endometrial cancer patients available for the study and collected the following parameters: age, body mass index, stage, menopause, Lynch syndrome status, parity, hypertension, type of localization of the lesion at hysteroscopy, type of surgery and complications, and presence of metachronous or synchronous tumors. The tumors were classified according to the European Society for Medical Oncology, Proactive Molecular Risk Classifier for Endometrial Cancer, Post-Operative Radiation Therapy in Endometrial Carcinoma, and Cancer Genome Atlas classification schemes. Our data confirmed that European Society for Medical Oncology risk was the strongest predictor of prognosis in our cohort. The parameters correlated with poor prognosis were the histotype, FIGO stage, and grade. Our study cohort shows that risk stratification should be based on the integration of histologic, clinical, and molecular parameters.

Palmitate Enhances the Efficacy of Cisplatin and Doxorubicin against Human Endometrial Carcinoma Cells

Endometrial cancer is the most common gynecological cancer worldwide. At present there is no effective screening test for its early detection and no curative treatment for women with advanced-stage or recurrent disease. Overexpression of fatty acid synthase is a common molecular feature of a subgroup of sex steroid-related cancers associated with poor prognoses, including endometrial cancers. Disruption of this fatty acid synthesis leads to cell apoptosis, making it a potential therapeutic target. The saturated fatty acid palmitate reportedly induces lipotoxicity and cell death by inducing oxidative stress in many cell types. Here, we explored the effects of palmitate combined with doxorubicin or cisplatin in the HEC-1-A and RL95-2 human endometrial cancer cell lines. The results showed that physiological concentrations of exogenous palmitate significantly increased cell cycle arrest, DNA damage, autophagy, and apoptosis in both RL95-2 and HEC-1-A cells. It also increased the chemosensitivity of both cell types. Notably, we did not observe that palmitate lipotoxicity reflected increased levels of reactive oxygen species, suggesting palmitate acts via a different mechanism in endometrial cancer. This study thus provides a potential therapeutic strategy in which palmitate is used as an adjuvant in the treatment of endometrial cancer.

Insulin Resistance and Metabolic Syndrome Increase the Risk of Relapse For Fertility Preserving Treatment in Atypical Endometrial Hyperplasia and Early Endometrial Cancer Patients

Objective

Fertility-sparing treatment for young women with atypical endometrial hyperplasia (AEH) and early endometrial cancer (EC) is a difficult challenge. Insulin resistance (IR) and metabolic syndrome (MetS) are two potentially crucial, but currently enigmatic factors in the recurrence of AEH and early EC patients. In this study we attempt to elucidate these factors.

Methods

A retrospective study was conducted from January 2010 to December 2019. Risk factors for recurrence and complete remission time after recurrence (RCR time) were investigated. ROC curves were built to estimate the accuracy of the metabolic characteristics and Kaplan-Meier (K-M) analysis was used to calculate recurrence-free survival (RFS) for patients with various IR or MetS statuses.

Results

A total of 111 AEH or early EC patients met the criteria and were enrolled in our study. Univariate analysis found that BMI ≥25 kg/m² (OR = 2.7, 95% CI: 1.1-6.4, P = 0.03), IR (OR = 9.5, 95% CI: 3.3-27.0, P <0.001), MetS (OR = 4.9, 95% CI:1.5-15.5, P = 0.008), IR+ and MetS+ (OR = 21.0, 95% CI: 4.8-92.7, P <0.001), histological type (OR = 3.5, 95% CI: 1.5-7.9, P = 0.003), and maintenance treatment (OR = 0.3, 95% CI: 0.1-0.6, P = 0.005) were all significantly associated with recurrence and longer RCR time. Among these factors, IR and MetS were determined to be two independent risk factors for recurrence. Moreover, using IR and MetS as markers significantly improved the diagnostic accuracy of recurrence for fertility-sparing treatment patients (AUC = 0.818, P <0.05) and may play synergistic roles in suppressing treatment. K-M analysis indicated both metabolic features played important roles in RFS (P <0.05).

Conclusion

Both IR and MetS were significantly associated with recurrence and longer RCR time in AEH and early EC patients receiving fertility-sparing treatment.

Effects of Metabolic Syndrome and Its Components on the Prognosis of Endometrial Cancer

Objective

To explore the effects of metabolic syndrome (MetS) on the prognosis of endometrial cancer (EC) and to identify key components of MetS associated with EC.

Methods

A total of 506 patients surgically diagnosed with EC were analyzed in this study. These patients were diagnosed with EC in the Department of Obstetrics and Gynecology at the People's Hospital of Peking University between 2010 and 2016. The follow-up time was cut off at December 2019. MetS was characterized based on standards provided by the Chinese Diabetes Society in 2004.

Results

Among the 506 EC patients analyzed, 153 patients were diagnosed with MetS. MetS patients were more likely to be older and postmenopausal. MetS was positively related to tumor grade, stage, LNM, LVSI, and MI. The univariate analysis showed that MetS was closely related to the OS (HR = 2.14; P = 0.032) and RFS (HR = 1.80; P = 0.045) of EC patients. K-M analysis also indicated that EC patients with MetS had shorter OS and RFS than EC patients without MetS. More specifically, patients that had ≥3 components showed a worse outcome compared with patients only having 0 or 1-2 components (P <0.05). In the multivariate-adjust model, after adjusting for age, histotype, tumor grade, and stage, HDL-C was found to be associated with increased risk of death related to EC (HR = 2.2, P = 0.034). However, MetS did not significantly correlate with this. ROC analysis revealed that the area under the ROC curve of combined factors (HDL-C + grade + stage) was better than traditional stage or grade at 1-, 3-, and 5-year survival rates. From this, a nomogram based on HDL-C, grade, and stage was constructed to predict survival of EC patients. Calibration curve analysis and decision curve analysis (DCA) showed the nomogram we constructed could better predict the survival of EC patients.

Conclusion

MetS is closely related to poor prognosis in EC patients. The prevalence of individual MetS components increase with worse outcomes in EC patients. A nomogram based on HDL-C, grade, and stage has good ability to predict survival of EC patients.

Correlation of Metabolic Factors with Endometrial Atypical Hyperplasia and Endometrial Cancer: Development and Assessment of a New Predictive Nomogram

Purpose

This study aimed to investigate the association of metabolic factors with endometrial atypical hyperplasia and endometrial cancer, and to develop a nomogram model to predict the risk of developing endometrial cancer.

Patients and Methods

We collected data of patients with endometrial atypical hyperplasia and endometrial cancer as the case group and then selected patients with simple hyperplasia or polypoid hyperplasia of the endometrium during the same period as the control group using the age-matched method. Laboratory results of metabolic factors were retrieved from the clinical data of the two groups of patients. Multivariable logistic regression analysis was used to determine the risk factors associated with endometrial malignant hyperplasia and to develop a nomogram prediction model of risk factors associated with endometrial malignant hyperplasia. Discrimination, calibration, and clinical usefulness of the prediction model were assessed using the C-index, calibration plot, and decision curve analysis.

Results

Predictors included in the column line graph model were age, hypertension, diabetes, BMI, uric acid, and hyperlipidemia. We calculated the C-index of the model and performed bootstrap validation. Our nomogram model had good discriminatory power and was well calibrated. Decision curve analysis was also used to guide the practical application of this column line graph model.

Conclusion

The development of endometrial malignant hyperplasia is significantly associated with metabolic factors: BMI > 25, hyperuricemia, and hyperlipidemia are the main risk factors. Hypertension, hyperglycemia and elevated CA199 were also associated with the development of endometrial malignant hyperplasia. The nomogram prediction model based on physical examination and laboratory testing developed in this study can be used as a rapid method for predicting the risk of endometrial malignancy development and screening for risk factors in a population of women with metabolism-related high-risk factors.

Two Dimensional-Difference in Gel Electrophoresis (2D-DIGE) Proteomic Approach for the Identification of Biomarkers in Endometrial Cancer Serum

Endometrial cancer is the most common gynecologic malignancy arising from the endometrium. Identification of serum biomarkers could be beneficial for its early diagnosis. We have used 2D-Difference In Gel Electrophoresis (2D-DIGE) coupled with Mass Spectrometry (MS) procedures to investigate the serum proteome of 15 patients with endometrial cancer and 15 non-cancer subjects. We have identified 16 proteins with diagnostic potential, considering only spots with a fold change in %V ≥ 1.5 or ≤0.6 in intensity, which were statistically significant (p < 0.05). Western blotting data analysis confirmed the upregulation of CLU, ITIH4, SERPINC1, and C1RL in endometrial and exosome cancer sera compared to those of control subjects. The application of the logistic regression constructed based on the abundance of these four proteins separated the controls from the cancers with excellent levels of sensitivity and specificity. After a validation phase, our findings support the potential of using the proposed algorithm as a diagnostic tool in the clinical stage.

Immunotherapy in endometrial cancer: rationale, practice and perspectives

Tumor immunotherapy has attracted more and more attention nowadays, and multiple clinical trials have confirmed its effect in a variety of solid tumors. Immune checkpoint inhibitors (ICIs), cancer vaccines, adoptive cell transfer (ACT), and lymphocyte-promoting cytokines are the main immunotherapy methods. Endometrial cancer (EC) is one of the most frequent tumors in women and the prognosis of recurrent or metastatic EC is poor. Since molecular classification has been applied to EC, immunotherapy for different EC subtypes (especially POLE and MSI-H) has gradually attracted attention. In this review, we focus on the expression and molecular basis of the main biomarkers in the immunotherapy of EC firstly, as well as their clinical application significance and limitations. Blocking tumor immune checkpoints is one of the most effective strategies for cancer treatment in recent years, and has now become the focus in the field of tumor research and treatment. We summarized clinical date of planned and ongoing clinical trials and introduced other common immunotherapy methods in EC, such as cancer vaccine and ACT. Hormone aberrations, metabolic syndrome (MetS) and p53 mutant and that affect the immunotherapy of endometrial cancer will also be discussed in this review.

Identification of a Metabolism-Related Signature for the Prediction of Survival in Endometrial Cancer Patients

Objective

Endometrial cancer (EC) is one of the most common gynecologic malignancies. The present study aims to identify a metabolism-related biosignature for EC and explore the molecular immune-related mechanisms underlying the tumorigenesis of EC.

Methods

Transcriptomics and clinical data of EC were retrieved from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Common differentially expressed metabolism-related genes were extracted and a risk signature was identified by using the least absolute shrinkage and selection operator (LASSO) regression analysis method. A nomogram integrating the prognostic model and the clinicopathological characteristics was established and validated by a cohort of clinical EC patients. Furthermore, the immune and stromal scores were observed and the infiltration of immune cells in EC cells was analyzed.

Results

Six genes, including CA3, HNMT, PHGDH, CD38, PSAT1, and GPI, were selected for the development of the risk prediction model. The Kaplan-Meier curve indicated that patients in the low-risk group had considerably better overall survival (OS) (P = 7.874e-05). Then a nomogram was constructed and could accurately predict the OS (AUC = 0.827, 0.821, 0.845 at 3-, 5-, and 7-year of OS). External validation with clinical patients showed that patients with low risk scores had a longer OS (p = 0.04). Immune/stromal scores and infiltrating density of six types of immune cells were lower in high-risk group.

Conclusions

In summary, our work provided six potential metabolism-related biomarkers as well as a nomogram for the prognosis of EC patients, and explored the underlying mechanism involved in the progression of EC.

Contribution of RAGE axis activation to the association between metabolic syndrome and cancer

Far beyond the compelling proofs supporting that the metabolic syndrome represents a risk factor for diabetes and cardiovascular diseases, a growing body of evidence suggests that it is also a risk factor for different types of cancer. However, the involved molecular mechanisms underlying this association are not fully understood, and they have been mainly focused on the individual contributions of each component of the metabolic syndrome such as obesity, hyperglycemia, and high blood pressure to the development of cancer. The Receptor for Advanced Glycation End-products (RAGE) axis activation has emerged as an important contributor to the pathophysiology of many clinical entities, by fueling a chronic inflammatory milieu, and thus supporting an optimal microenvironment to promote tumor growth and progression. In the present review, we intend to highlight that RAGE axis activation is a crosswise element on the potential mechanistic contributions of some relevant components of metabolic syndrome into the association with cancer.

Characteristics of progestin-insensitive early stage endometrial cancer and atypical hyperplasia patients receiving second-line fertility-sparing treatment

Objective

This study investigated the characteristics of progestin-insensitive endometrioid endometrial cancer (EEC) and atypical endometrial hyperplasia (AEH) patients receiving fertility-sparing treatments and assessed the therapeutic effects of second-line fertility-preserving treatments.

Methods

Three hundred and thirty-eight patients with EEC (n=75) or AEH (n=263) receiving fertility-preserving treatment were retrospectively analyzed. ‘Progestin-insensitive’ was defined as meeting one of the following criteria: 1) presented with progressed disease at any time during conservative treatment, 2) remained with stable disease after 7 months of treatment, and/or 3) did not achieve complete response (CR) after 10 months of treatment. Clinical characteristics and treatment results of progestin-insensitive patients receiving second-line treatment and those of progestin-sensitive patients were compared.

Results

Eight-two patients (59 AEH and 23 EEC) were defined as progestin-insensitive and 256 as progestin-sensitive. In multivariate analysis, body mass index ≥28.0 kg/m² (odds ratio [OR]=1.898) and lesion size >2 cm (OR=2.077) were independent predictors of progestin-insensitive status. Compared to AEH patients, progestin-insensitive EEC patients had poorer second-line treatment responses (28-week cumulative CR rate after changing second-line treatment, 56.3% vs. 85.4%, p=0.011). No statistical difference was found in CR rate among different second-line treatments.

Conclusion

Obesity and larger lesion size were independent risk factors associated with progestin-insensitive status. In progestin-insensitive patients receiving second-line treatment, EEC patients had lower CR rate comparing with AEH patients. Further study with larger sample size is needed to evaluate efficacy of different second-line treatments for progestin insensitive patients.

The Central Roles of Noncoding RNA in Estrogen-Dependent Female Reproductive System Tumors

The pathogenesis of ovarian and endometrial cancers is closely associated with estrogen-related pathways. These estrogen-dependent tumors seriously threaten the health and quality of life in women. Noncoding RNAs (ncRNAs) are defined as RNAs that do not encode proteins, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), both of which have been reported in estrogen-dependent female reproductive system tumors. This review systematically summarizes the role of ncRNAs in estrogen-dependent tumors and common patterns of regulatory mechanisms to explore their future research directions in tumor diagnosis, treatment, and prognosis. This may provide new ideas for the potential application of ncRNAs in estrogen-dependent female reproductive system tumors.

Endometrial cancer-is our knowledge changing?

In developed countries, endometrial cancer (EC) is the most frequent gynecologic malignancy in postmenopausal women. At the same time, EC has become one of the most common cancers in numerous developing countries, probably influenced by global epidemic of obesity. The majority of patients have low-grade endometrioid cancer with a high 5-year survival rate, but with high-risk EC, the survival rates are still rather low. However, despite intensive research in last decades, our knowledge of the mechanisms, risk factors, diagnosis and treatment have not significantly improved. The standard treatment of all types of EC is still a traditional combination of surgery, irradiation and/or chemotherapy, despite the fact that each of these options is not without having some negative side effects. Despite the fact that on the molecular level, EC is relatively well-studied, but the efforts to transform these findings into either diagnosis or therapies of EC remain elusive. In addition, some research into risk factors involved in the development or progression of EC seems to be more a fishing expedition than a well thought-out approach. The purpose of this review is to summarize the most recent developments in the search for biomarkers and prognostic markers and to discuss the progress in EC treatment.

Low Red Blood Cell Count as an Early Indicator for Myometrial Invasion in Women with Endometrioid Endometrial Carcinoma with Metabolic Syndrome

Purpose

We investigated the relationship between metabolic syndrome (MetS) and its components and erythrocyte parameters such as red blood cell count (RBC) and hemoglobin (Hb) levels, and their association with the risk of deep myometrial invasion in endometrioid endometrial carcinoma (EEC).

Patients and Methods

A total of 473 women diagnosed with EEC between January 2012 and December 2018 were included in the study. MetS was diagnosed using a modified version of the Chinese Diabetes Society 2004 criteria. Demographic and clinical characteristics were stratified by MetS and compared. Logistic regression analyses were performed to calculate the odds ratios (ORs) of myometrial invasion.

Results

The prevalence of MetS was 18.8% (89/473). RBC and Hb levels were significantly higher in EEC patients with MetS. RBC and Hb values increased linearly with the number of MetS components. The OR of the MetS risk increased across the RBC quartiles (OR=2.212, 95% confidence interval [Cl]=1.125-4.350, P˂0.05). Among EEC patients with MetS, the OR of deep myometrial invasion increased with the decrease of the RBC quartiles (P=0.037). Similarly, in EEC patients with obesity and hyperglycemia or with ≥2 MetS criteria, the lowest RBC level (Q1) was a risk factor for deep myometrial invasion compared with the reference RBC group (Q4, P˂0.05). However, this trend was not evident in EEC patients without MetS and its components.

Conclusion

EEC with MetS and its components had higher RBC and Hb levels. The association between the erythrocyte parameters and myometrial invasion differed with MetS. RBC was identified as a risk factor of myometrial invasion in EEC patients with MetS and its components.

Current mechanisms in obesity and tumor progression

PURPOSE OF REVIEW

Hyperadiposity, as present in obesity, is a substantial threat to cancer risk and prognosis. Studies that have investigated the link between obesity and tumor progression have proposed several mechanistic frameworks, yet, these mechanisms are not fully defined. Further, a comprehensive understanding of how these various mechanisms may interact to create a dynamic disease state is lacking in the current literature.

RECENT FINDINGS

Recent work has begun to explore not only discrete mechanisms by which obesity may promote tumor growth (for instance, metabolic and growth factor functions of insulin; inflammatory cytokines; adipokines; and others), but also how these putative tumor-promoting factors may interact.

SUMMARY

This review will highlight the present understanding of obesity, as it relates to tumor development and progression. First, we will introduce the impact of obesity in cancer within the dynamic tumor microenvironment, which will serve as a theme to frame this review. The core of this review will discuss recently proposed mechanisms that implicate obesity in tumor progression, including chronic inflammation and the role of pro-inflammatory cytokines, adipokines, hormones, and genetic approaches. Furthermore, we intend to offer current insight in targeting adipose tissue during the development of cancer prevention and treatment strategies.

Expression of voltage-dependent anion channels in endometrial cancer and its potential prognostic significance

The exchange of metabolites between mitochondria and cytosol occurs through pores formed by voltage-dependent anion channel proteins. Voltage-dependent anion channels appear to be master regulators of mitochondrial bioenergetics and the intracellular flow of energy. Deregulation of voltage-dependent anion channels expression is thought to be related to mitochondrial dysfunction in cancer. The aim of this study was to investigate the mRNA and protein expression levels of VDAC1, VDAC2, and VDAC3 in relation to clinicopathological characteristics of endometrial cancer as well as the prognostic significance of voltage-dependent anion channels expression for overall survival. VDAC1 and VDAC3 expressions were significantly higher in cancer compared to normal tissues. Kaplan-Meier analysis indicated that high expression of all VDAC genes or high VDAC2 protein level predicted poor overall survival. Multivariate analysis identified the VDAC1 and VDAC2 mRNA levels as well as VDAC2 protein level as independent prognostic factors. Our results suggest that increased expression of voltage-dependent anion channels correlates with tumor progression and may serve as a potential prognostic biomarker in endometrial cancer.

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.

Regional distribution of Christensenellaceae and its associations with metabolic syndrome based on a population-level analysis

The link between the gut microbiota and metabolic syndrome (MetS) has attracted widespread attention. Christensenellaceae was recently described as an important player in human health, while its distribution and relationship with MetS in Chinese population is still unknown. This study sought to observe the association between Christensenellaceae and metabolic indexes in a large sample of residents in South China. A total of 4,781 people from the GGMP project were included, and the fecal microbiota composition of these individuals was characterized by 16S rRNA sequencing and analyzed the relation between Christensenellaceae and metabolism using QIIME (Quantitative Insight Into Microbial Ecology, Version 1.9.1). The results demonstrated that microbial richness and diversity were increased in the group with a high abundance of Christensenellaceae, who showed a greater complexity of the co-occurrence network with other bacteria than residents who lacked Christensenellaceae. The enriched bacterial taxa were predominantly represented by Oscillospira, Ruminococcaceae, RF39, Rikenellaceae and Akkermansia as the Christensenellaceae abundance increased, while the abundances of Veillonella, Fusobacterium and Klebsiella were significantly reduced. Furthermore, Christensenellaceae was negatively correlated with the pathological features of MetS, such as obesity, hypertriglyceridemia and body mass index (BMI). We found reduced levels of lipid biosynthesis and energy metabolism pathways in people with a high abundance of Christensenellaceae, which may explain the negative relationship between body weight and Christensenellaceae. In conclusion, we found a negative correlation between Christensenellaceae and MetS in a large Chinese population and reported the geographical distribution of Christensenellaceae in the GGMP study. The association data from this population-level research support the investigation of strains within Christensenellaceae as potentially beneficial gut microbes.

Metabolomic Biomarkers for Detection, Prognosis and Identifying Recurrence in Endometrial Cancer

Metabolic reprogramming is increasingly recognised as one of the defining hallmarks of tumorigenesis. There is compelling evidence to suggest that endometrial cancer develops and progresses in the context of profound metabolic dysfunction. Whilst the incidence of endometrial cancer continues to rise in parallel with the global epidemic of obesity, there are, as yet, no validated biomarkers that can aid risk prediction, early detection, prognostic evaluation or surveillance. Advances in high-throughput technologies have, in recent times, shown promise for biomarker discovery based on genomic, transcriptomic, proteomic and metabolomic platforms. Metabolomics, the large-scale study of metabolites, deals with the downstream products of the other omics technologies and thus best reflects the human phenotype. This review aims to provide a summary and critical synthesis of the existing literature with the ultimate goal of identifying the most promising metabolite biomarkers that can augment current endometrial cancer diagnostic, prognostic and recurrence surveillance strategies. Identified metabolites and their biochemical pathways are discussed in the context of what we know about endometrial carcinogenesis and their potential clinical utility is evaluated. Finally, we underscore the challenges inherent in metabolomic biomarker discovery and validation and provide fresh perspectives and directions for future endometrial cancer biomarker research.

Immune disorder in endometrial cancer: Immunosuppressive microenvironment, mechanisms of immune evasion and immunotherapy

Immunotherapy is an emerging clinical approach that has gained traction over the past decade as a novel treatment option for lung cancer and melanoma. Notably, researchers have made marked improvements in the treatment of endometrial cancer (EC), and potential immune responses have been identified in patients with EC, thereby offering the possibility of exploring immunotherapy for EC. Nevertheless, various needs remain unmet, and immunotherapy applications in EC have yielded limited success, as only a minority of patients exhibited a clinical response. Therefore, further understanding of immune dysfunction associated with EC is still required. The present review describes recent findings regarding the immunosuppressive microenvironment of EC, with emphasis on immune evasion mechanisms and immunotherapy in EC.

Increased Serum Calcium Level Promotes the Risk of Lymph Node Metastasis in Endometrial Cancer

Purpose

The early predictive values of diagnostic markers for lymph node metastasis (LNM) in endometrial cancer (EC) are still unclear at present. The purpose of this study is to explore the relationship between serum calcium and LNM in EC.

Methods

We identified all patients with EC who underwent surgery between January 2012 and December 2016. Patient characteristics and various preoperative clinicopathologic data were obtained from medical records and were reviewed retrospectively. These patients were divided into two groups according to the pathology of their lymph node. Logistic regression models analyzed the relationship between the ionized calcium and LNM of EC patients, while adjusting for the potential confounders.

Results

A total of 448 patients were assessed. Univariate analysis showed that ionized calcium, CA125 level, tumor grade, peritoneal cytology, FIGO stage, histological type, LVSI, and myometrial invasion were positively correlated with LNM (all P<0.05). The risk of LNM increased with the promotion of serum ionized calcium (P for trend <0.01). Ionized calcium level was significant before and after the adjustment of cofounders (unadjusted: OR=11.9, 95% CI: 4.8-29.6, P< 0.01; model I: OR=11.3, 95% CI: 4.5-28.8, P< 0.01; model II: OR=5.2, 95% CI: 1.6-17.2, P< 0.05). Additionally, the risk of ionized calcium was especially evident in patients whose age was older than 60, BMI<28 kg/m², grade 3, negative peritoneal cytology and endometrioid endometrial adenocarcinoma.

Conclusion

Ionized calcium level was highly associated with LNM in EC and acted as a potential biomarker in predicting the risk of LNM in EC.

The NF-κB signalling pathway regulates GLUT6 expression in endometrial cancer

BACKGROUND

Gene and protein expression of the glucose transporter GLUT6 are elevated in multiple cancers, including endometrial cancer. However, the extrinsic and intrinsic mechanisms that regulate GLUT6 expression in this malignancy are unknown. Herein we investigate the potential mechanisms regulating GLUT6 expression in endometrial cancer.

METHODS

Data mining of the GLUT6 gene (SLC2A6) in The Cancer Genome Atlas (TCGA) PanCan datasets was performed in cBioPortal. A transcriptome PCR array was used to identify regulators of GLUT6 expression. The role of RELA in regulating GLUT6 gene and protein expression was investigated by overexpressing constitutively active and dominant-negative RELA in endometrial cells. Endometrial cells were treated with the pro-inflammatory cytokine TNFα and the expression of RELA, IκBα, TNFα, and GLUT6 were examined by Western blotting and RT-qPCR.

RESULTS

GLUT6 is altered in 1% of all cancer samples (157 of 10, 967 samples) within TCGA datasets including 4.7% of uterine (endometrial) cancers. GLUT6 expression was positively co-expressed with multiple members of the NF-κB signalling pathway including NFKB2, RELB, NFKBIE, and TNF in endometrial cancer samples. A transcriptome PCR array identified RELA as the top potential transcriptional regulator of GLUT6 expression. Overexpression of constitutively active RELA increased GLUT6 gene expression in normal endometrial epithelial cells (hUE-Ts), while overexpression of dominant-negative RELA decreased GLUT6 expression in cancerous RL95-2 endometrial cells. TNFα treatment activated canonical NF-κB signalling and increased the expression of GLUT6, but not that of other glucose transporters (GLUTs 1, 3, 4, 8, 10, or 12) in endometrial cells.

CONCLUSIONS

TNFα is a cytokine that is commonly increased in obesity-related endometrial cancer and the findings herein support a potential mechanism whereby TNFα may contribute to endometrial cancer initiation or progression by increasing GLUT6 expression. Furthermore, we identified RELA, an important downstream mediator of the TNFα signalling cascade, as a regulator of GLUT6 expression in endometrial cells. Future studies are warranted to determine how GLUT6 expression affects endometrial tumourigenesis or cancer progression.

Association between metabolic syndrome and endometrial cancer risk: a systematic review and meta-analysis of observational studies

Existing evidence has revealed inconsistent results on the association between metabolic syndrome (MetS) and endometrial cancer (EC) risk. Herein, we aim to better understand this association. Systematic searches of PubMed, EMBASE, and Web of Science through 12 December 2019 were conducted. Observational studies that provided risk estimates of MetS and EC risk were eligible. The quality of the included studies was judged based on the Newcastle–Ottawa scale. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Six studies, comprising 17,772 EC cases and 150,371 participants were included. MetS, diagnosed according to the criteria of the National Cholesterol Education Program—Third Adult Treatment Panel, was associated with an increased risk of EC (OR: 1.62; 95% CI = 1.26–2.07) with substantial heterogeneity (I² = 78.3%). Furthermore, we found that women with MetS, diagnosed according to the criteria of the International Diabetes Federation, had a significantly higher risk of EC compared to healthy controls (OR: 1.45; 95% CI = 1.16–1.81; I² = 64.6%). Our findings were generally consistent with the main results in the majority of prespecified subgroups, as well as in sensitivity analyses. In conclusion, MetS is associated with EC risk.

The Role of Hyperglycemia in Endometrial Cancer Pathogenesis

Endometrial cancer is one of the most common cancers in women worldwide and its incidence is increasing. Epidemiological evidence shows a strong association between endometrial cancer and obesity, and multiple mechanisms linking obesity and cancer progression have been described. However, it remains unclear which factors are the main drivers of endometrial cancer development. Hyperglycemia and type 2 diabetes mellitus are common co-morbidities of obesity, and there is evidence that hyperglycemia is a risk factor for endometrial cancer independent of obesity. This review aims to explore the association between hyperglycemia and endometrial cancer, and discuss the evidence supporting a role for increased glucose metabolism in endometrial cancer and how this phenotype may contribute to endometrial cancer growth and progression. Finally, the potential role of blood glucose lowering strategies, including drugs and bariatric surgery, for the treatment of this malignancy will be discussed.