Endometrial Carcinoma: Immune Microenvironment and Emerging Treatments in Immuno-Oncology

Single-cell RNA sequencing in endometrial cancer: exploring the epithelial cells and the microenvironment landscape

Single-cell RNA sequencing (scRNA-seq) technology has emerged as a powerful tool for dissecting cellular heterogeneity and understanding the intricate biology of diseases, including cancer. Endometrial cancer (EC) stands out as the most prevalent gynecological malignancy in Europe and the second most diagnosed worldwide, yet its cellular complexity remains poorly understood. In this review, we explore the contributions of scRNA-seq studies to shed light on the tumor cells and cellular landscape of EC. We discuss the diverse tumoral and microenvironmental populations identified through scRNA-seq, highlighting the implications for understanding disease progression. Furthermore, we address potential limitations inherent in scRNA-seq studies, such as technical biases and sample size constraints, emphasizing the need for larger-scale research encompassing a broader spectrum of EC histological subtypes. Notably, a significant proportion of scRNA-seq analyses have focused on primary endometrioid carcinoma tumors, underscoring the need to incorporate additional histological and aggressive types to comprehensively capture the heterogeneity of EC. By critically evaluating the current state of scRNA-seq research in EC, this review underscores the importance of advancing towards more comprehensive studies to accelerate our understanding of this complex disease.

Antitumor immunity and prognosis value elicited by FAT3 and LRP1B co-mutation in endometrial cancer

OBJECTIVE

FAT3 and LRP1B are two tumor suppressor genes with high mutation frequency in multiple cancer types, we sought to investigate the prognostic and immunological significance of these two genes in EC.

METHODS

Based on a cohort of 502 EC samples, we conducted a comprehensive analysis of its multidimensional data types including genomic, transcriptomic, and clinical information, the potential impact of FAT3 and LRP1B co-mutation on antitumor immune response and prognosis were systematically discussed.

RESULTS

We observed that FAT3 and LRP1B co-mutation was not only defined a dataset with prominently increased TMB, decreased tumor aneuploidy, and specially enriched in MSI-H subtype, but also manifested increased expression of immune-related markers, especially exclusive upregulation of PD-L1 levels and higher PD-L1+/CD8A+ proportion. Further analysis focused on lymphocyte infiltration and pathway enrichment explored the immune cell composition of the microenvironment and underlying molecular mechanisms affecting tumor development. Furthermore, EC patients with FAT3 and LRP1B co-mutation possessed significantly prolonged PFS and OS, and the co-mutation status was proved to be an independent prognostic factor. And a nomogram with high predictive performance was constructed by incorporating co-mutation with clinical features. More strikingly, the prognosis of MSI-H patients in EC with co-mutation was significantly improved, and their survival reached a level consistent with the POLE subtype.

CONCLUSIONS

In endometrial cancer, co-mutation of FAT3 and LRP1B not only leads to activation of the immune state, but also represents a subgroup with an improved prognosis, particularly in the MSI-H subtype.

Correlation of BUB1 and BUB1B with the development and prognosis of endometrial cancer

This study aimed to evaluate the expression and clinical significance of budding uninhibited by benzimidazole 1 (BUB1) and BUB1 mitotic checkpoint serine/threonine kinase B (BUB1B) in endometrial carcinoma (EC). BUB1 and BUBIB expressions were evaluated by bioinformatics. Protein expression, clinical features, prognosis and immune cell infiltration were explored in 20 EC tumors. siRNA was used to evaluate BUB1 and BUBIB function in EC cells. BUB1 and BUBIB were highly expressed in 26 cancers. BUB1 was associated with overall survival (OS) in eight cancers and disease-free survival in ten; BUB1B was associated with OS in nine cancers and DFS in eleven. BUB1 and BUBIB exhibited high frequencies of gene changes (mainly mutations, > 5%) in cancer. BUB1 was negatively correlated and BUB1B was positively correlated with cancer-associated fibroblasts and endothelial cell infiltration. BUB1 and BUBIB knockdown decreased migration and invasion in EC cells. High BUB1 expression correlated with tumor malignant phenotypes (P < 0.05). High BUB1 mRNA expression reduced OS (P = 0.00036) and recurrence-free survival (P = 0.0011). High BUB1B mRNA expression reduced OS (P = 0.0024). BUB1/BUB1B correlated with activated CD8 + T and CD4 + T cell infiltration. BUB1 and BUBIB are highly expressed and correlated with clinicopathological characteristics in EC. BUB1 and BUBIB are potential prognosis markers and immunotherapy targets.

Overexpression of zinc finger DHHC-type containing 1 is associated with poor prognosis and cancer cell growth and metastasis in uterine corpus endometrial carcinoma

The zinc finger DHHC-type containing 1 (ZDHHC1) gene is implicated in the pathogenesis and progression of various malignant tumors, but its precise involvement in uterine corpus endometrial carcinoma (UCEC) remains unknown. Thus, this study investigated ZDHHC1 expression in UCEC using publicly available TCGA and Xena databases and elucidated the functions and mechanisms of the ZDHHC1 gene in UCEC progression using bioinformatics and in vitro experiments. The correlation between ZDHHC1 expression and prognosis, clinical features, immune cells, and RNA modifications of UCEC was evaluated using nomograms, correlation, ROC, and survival analyses. The impacts of ZDHHC1 overexpression on UCEC progression and mechanisms were explored with bioinformatics and in vitro experiments. Our study revealed that ZDHHC1 expression was significantly downregulated in UCEC and correlated with poor prognosis, cancer diagnosis, clinical stage, age, weight, body mass index, histological subtypes, residual tumor, tumor grade, and tumor invasion. Notably, Cox regression analysis and constructed nomograms showed that downregulated ZDHHC1 expression was a prognostic factor associated with poor prognosis in patients with UCEC. Conversely, above-normal ZDHHC1 expression inhibited the cell growth, cell cycle transition, migration, and invasion of UCEC cells, which may be related to the cell cycle, DNA replication, PI3K-AKT, and other pathways that promote tumor progression. Altered ZDHHC1 expression in UCEC was significantly associated with RNA modifications and the changes in cancer immune cell populations, such as CD56 bright NK cells, eosinophils, Th2 cells, and cell markers. In conclusion, considerably reduced ZDHHC1 expression in UCEC is associated with cancer cell growth, metastasis, poor prognosis, immune infiltration, and RNA modifications, revealing the promising potential of ZDHHC1 as a prognostic marker for UCEC.

Machine learning combined with single-cell analysis reveals predictive capacity and immunotherapy response of T cell exhaustion-associated lncRNAs in uterine corpus endometrial carcinoma

BACKGROUND

The exhaustion of T-cells is a primary factor contributing to immune dysfunction in cancer. Long non-coding RNAs (lncRNAs) play a significant role in the advancement, survival, and treatment of Uterine Corpus Endometrial Carcinoma (UCEC). Nevertheless, there has been no investigation into the involvement of lncRNAs associated with T-cell exhaustion (TEXLs) in UCEC. The goal of this work is to establish predictive models for TEXLs in UCEC and study their related immune features.

METHODS

Using transcriptome and single-cell sequencing data from The Cancer Genome Atlas and Gene Expression Omnibus databases, we employed co-expression analysis and univariate Cox regression to identify prognostic-associated TEXLs (pTEXLs). The prognostic model was developed using the Least Absolute Contraction and Selection Operator. The immunotherapy characteristics of the prognostic model risk score were studied. Then molecular subgroups were identified through non-negative Matrix Factorization based on pTEXLs. The identification of co-expressed genes was done using a weighted correlation network analysis. Subsequently, a diagnostic model for UCEC was created. In-depth investigations, both in vitro and in vivo, were carried out to elucidate the molecular mechanism of the key gene within the diagnostic model.

RESULTS

Receiver operating characteristic curve, calibration curve, and decision curve analysis proved the validity of the predictive models established according to pTEXLs. The subgroup with lower risk scores in the prognostic model has better responses to blocking immune checkpoint therapy. Single-cell analysis suggests that the expression level of MIEN1 is relatively high in immune cells among diagnostic genes. Furthermore, the targeted suppression of MIEN1 via sh-MIEN1 diminishes the proliferative, migratory, and invasive capacities of UCEC cells, potentially associated with CD8+ T cell exhaustion.

CONCLUSIONS

The association between TEXLs and UCEC was methodically elucidated by our investigation. A stable pTEXLs risk prediction model and a diagnosis model for UCEC were also established.

Evaluation of the genetic diversity of KIR genes in patients with endometrial cancer

Endometrial cancer (EC) constitutes more than half of all genital cancers in women, with an increasing incidence in different countries. Natural killer cells (NK cells) are kinds of innate immune cells that are controlled by sets of receptors, such as killer cell Ig-like receptors (KIRs), which can inhibit or activate NK cells. In this study, we evaluated the diversity and genetic association of KIRs in confirmed cases of endometrial cancer compared to healthy controls. A total of 151 women with EC and 167 age/race-matched healthy controls were analyzed for KIR genes. Demographic and histopathologic data were gathered in questionnaires, and 16 KIR genes along with two variants of KIR2DS4 (KIR2DS4fl and KIR2DS4del), were genotyped by usingsequence specific primers-polymerase chain reaction (SSP-PCR) method. A comparison between cases and controls revealed that although there were not any significant differences in A haplotype associated genes and also the variants of KIR2DS4 (p >0.05), B haplotype associated genes such as KIR2DS2 and KIR2DL2 decreased significantly in EC patients in comparison with healthy controls (p=0.03 and p=0.01, respectively). Furthermore, we found that EC mostly developed in cases with the AA genotype; however, the carriers of Bx and C4T4 genotypes were less frequent in patients with EC. Our results revealed that KIR2DS2 and KIR2DL2, along with Bx and C4T4 genotypes, have a protective impact against developing endometrial cancer in Iranians.

A comprehensive analysis of immunotherapy in advanced endometrial cancer (Review)

The morbidity and mortality rates of endometrial cancer (EC) are increasing yearly. Early-stage EC can be effectively treated through surgery or surgery combined with radiotherapy and chemotherapy. Advanced and recurrent EC is treated with chemotherapy and comprehensive treatment; however, the prognosis for patients at this disease stage is poor. Consequently, novel and effective treatment strategies are urgently required for these patients. Breakthrough progress has been made with the use of immunosuppressants in the treatment of EC, which have been included in treatment guidelines. In the present review, the etiology and classification of EC was outlined and the relevant scientific basis for the application of immunosuppressants in advanced and recurrent EC was discussed. The relevant published and ongoing clinical trials are also summarized. As such, the present review aimed to provide a scientific summary of immunotherapy of EC.

PD-1 and TIGIT coexpressing CD8 + CD103 + tissue-resident memory cells in endometrial cancer as potential targets for immunotherapy

BACKGROUND

Immunotherapy has shown promise in treating various cancers; however, its efficacy in endometrial cancer (EC) remains suboptimal owing to the complex dynamics of the tumour immune microenvironment. This study focuses on exploring the potential of targeting the programmed cell death protein 1 gene (PD-1) and the T cell Immunoreceptor with Ig and ITIM domains gene (TIGIT) coexpressing tissue-resident memory cells in EC.

METHODS

A comprehensive approach, utilizing RNA sequencing, single-cell RNA sequencing, mass cytometry, and flow cytometry, was employed to analyse the expression patterns of PD-1 and TIGIT in the EC tumor environment and to characterize the phenotypic properties of tumor-infiltrating lymphocytes (TILs), particularly tissue-resident memory (TRM) cells. Additionally, in vitro cell experiments were conducted to assess the functional impact of PD-1 and TIGIT blockade on T-cell activity.

RESULTS

Our analysis identified a significant co-expression of PD-1 and TIGIT in TRM cells within the EC tumor microenvironment. These TRM cells displayed an exhausted phenotype with impaired cytotoxicity, enhanced proliferative capacity, and diminished cytotoxic activity. In vitro T-cell assays showed that a dual blockade of PD-1 and TIGIT more effectively restored T-cell functionality compared to single blockade, suggesting enhanced therapeutic potential.

CONCLUSIONS

TRM cells co-expressing PD-1 and TIGIT represent potential targets for EC immunotherapy. Dual immune checkpoint blockade targeting PD-1 and TIGIT may offer an effective therapeutic strategy for EC, providing valuable insights for the development of immunotherapeutic approaches.

Effectiveness and safety of PD-1/PD-L1 inhibitors in advanced or recurrent endometrial cancer: a systematic review and meta-analysis

Background: Studies in recent years have shown that PD-1/PD-L1 inhibitors may have better effectiveness in patients with advanced or recurrent endometrial cancer. The effectiveness of PD-1/PD-L1 inhibitors is thought to be related to mismatch repair-deficient (dMMR) and mismatch repair-proficient (pMMR) classification in advanced or recurrent endometrial cancer. This study aims to evaluate the effectiveness of PD-1/PD-L1 inhibitors in patients classified as dMMR and pMMR. Methods: Medical databases were searched to identify relevant publications up to 30 November 2022. The primary outcome was comparison of objective response rate (ORR) in patients with dMMR and pMMR following treatment with PD-1/PD-L1 inhibitors; secondary outcomes were single-group ORR in patients with dMMR and in patients with pMMR, respectively. Results: Eleven studies were eligible for analysis and patients with advanced or recurrent endometrial cancer with molecular classification of dMMR had a higher total ORR than those with pMMR [odds ratio (OR), 7.70; 95% confidence interval (CI), 3.22-18.38; p < 0.01], with low evidence of between-study heterogeneity (I2 = 0%). The total ORR of patients with advanced or recurrent endometrial cancer with molecular type dMMR was 51.9% (95% CI, 33.6%-69.9%). The overall ORR of patients with advanced or recurrent endometrial cancer with molecular type pMMR was 16.1% (95% CI, 5.5%-30.3%). Conclusion: In our including studies, the patients with advanced or recurrent endometrial cancer with molecular types of dMMR and pMMR, following treatment with PD-1/PD-L1 inhibitors, the total ORR of patients with dMMR was higher than that of patients with pMMR. Since the current number of studies is not very large, it is possible that more studies will be published in the future and more precise results will be discussed further.

Association Between Intermediate End Points, Progression-free Survival, and Overall Survival in First-line Advanced or Recurrent Endometrial Cancer

PURPOSE

Advanced/recurrent endometrial cancer is associated with poor long-term outcomes. Clinical studies of novel regimens are ongoing, but given that data on overall survival (OS) take a long time to mature, surrogate end points are often used to support clinical-research interpretation. The aim of this study was to explore the correlation between progression-free survival (PFS)/time to progression (TTP) and OS across multiple time points in the first-line treatment of advanced/recurrent endometrial cancer.

METHODS

This study comprised meta-analyses of Phase 2/3 randomized, controlled trials of first-line treatments in patients with advanced primary or first-recurrent endometrial cancer identified via systematic literature review. The strength of the surrogacy relationship was assessed by correlation analyses (estimated with Spearman and Pearson correlation coefficients) and weighted linear regression.

FINDINGS

Data from 15 studies were included. PFS and TTP (TTP was reported in one study only) were highly correlated with future OS at multiple time points (Spearman values, 0.83-0.90; Pearson values, 0.86-0.93), suggesting that a change in PFS/TTP would likely be correlated with a change in OS in the same direction. On weighted linear regression, a 10% increase in PFS/TTP probability was significantly associated with a 9.3% to 13.3% increase in the probability of future OS. The strong positive association between PFS/TTP and OS was supported by findings from sensitivity analyses based on identified sources of interstudy heterogeneity.

IMPLICATIONS

PFS/TTP is a good potential candidate for predicting long-term OS outcomes in trials of first-line treatment in patients with advanced/recurrent endometrial cancer. The findings from this report may help to inform health-authority and clinical decision makers that PFS/TTP improvements are likely to translate into subsequent OS improvements once data mature.

Identification of immune-related gene signature for predicting prognosis in uterine corpus endometrial carcinoma

The objective of this study is to develop a gene signature related to the immune system that can be used to create personalized immunotherapy for Uterine Corpus Endometrial Carcinoma (UCEC). To classify the UCEC samples into different immune clusters, we utilized consensus clustering analysis. Additionally, immune correlation algorithms were employed to investigate the tumor immune microenvironment (TIME) in diverse clusters. To explore the biological function, we conducted GSEA analysis. Next, we developed a Nomogram by integrating a prognostic model with clinical features. Finally, we performed experimental validation in vitro to verify our prognostic risk model. In our study, we classified UCEC patients into three clusters using consensus clustering. We hypothesized that cluster C1 represents the immune inflammation type, cluster C2 represents the immune rejection type, and cluster C3 represents the immune desert type. The hub genes identified in the training cohort were primarily enriched in the MAPK signaling pathway, as well as the PD-L1 expression and PD-1 checkpoint pathway in cancer, all of which are immune-related pathways. Cluster C1 may be a more suitable for immunotherapy. The prognostic risk model showed a strong predictive ability. Our constructed risk model demonstrated a high level of accuracy in predicting the prognosis of UCEC, while also effectively reflecting the state of TIME.

ZAP70 interaction with 13 mRNAs as a potential immunotherapeutic target for endometrial cancer

For advanced, refractory endometrial cancer (EC), it is advisable to find effective immunotherapeutic targets. In the present study, genes affecting the immune status of uterine corpus endometrial carcinoma (UCEC) samples within The Cancer Genome Atlas were explored by weighted correlation network analysis and differential gene expression analysis. The protein function and immune correlation of 14 key genes, including ζ-chain-associated protein kinase 70 (ZAP70), were analyzed. Based on the expression levels of key genes, the patients with UCEC were divided into two groups using consensus clustering, low expression (group 1) and high expression (group 2). Next, the functions of differentially expressed genes (DEGs) between the two groups were identified using Gene Ontology enrichment analysis, Kyoto Encyclopedia of Genes and Genomes analysis and Gene Set Enrichment Analysis. The immune status of the patients in the two groups was evaluated using immune infiltration score and the expression levels of targets of immune checkpoint inhibitors. The role of ZAP70 in the prognosis of patients with UCEC and the differences in ZAP70 expression between EC tissues and healthy intimal tissues were determined by reverse transcription-quantitative PCR and immunohistochemistry. The present study found strong correlations between key genes, including ZAP70, LCK, FOXP3, TIGIT, CTLA4, ICOS, CD5, IL2RG, PDCD1, TNFRSF4, CD27, CCR7, GZMB, CXCL9. From the enrichment analyses, it was found that the functions of these DEGs were related to T cells. Patients in group 2 had stronger immune infiltration and higher immune checkpoints expression compared with those in group 1. ZAP70 was expressed at higher levels in EC tissues compared with in normal tissues, and may act as a protective factor in EC. In conclusion, ZAP70 interaction with 13 mRNAs may affect the immune status of patients with EC and may be a potential target for immunotherapy.

Tumor immune microenvironment in endometrial cancer of different molecular subtypes: evidence from a retrospective observational study

Objective

Tumor immune microenvironmental features may predict survival and guide treatment. This study aimed to comprehensively decipher the immunological features of different molecular subtypes of endometrial cancer.

Methods

In this retrospective study, 26 patients with primary endometrial cancer and four with recurrent disease treated in our center from December 2018 to November 2021 were included. Next-generation sequencing was performed on tumor samples. Patients were classified into four subtypes, including POLE mutant, microsatellite instability high (MSI-H), no specific molecular profile (NSMP) and TP53 mutant subtypes. Tumor-infiltrating immune cells were quantified using multiplex immunofluorescence assays.

Results

Of the 26 primary endometrial cancer cases, three were POLE mutant, six were MSI-H, eight were NSMP and nine were TP53 mutant. Of the four recurrent cases, two belonged to the NSMP subtype and two belonged to the TP53 mutant subtype. The tumor mutation burden (TMB) levels of POLE mutant and MSI-H cases were significantly higher than that of the other two subtypes (p< 0.001). We combined POLE mutant and MSI-H subtypes into the TMB high (TMB-H) subtype. The TMB-H subtype showed a high degree of infiltration of CD8⁺ T cells. In the NSMP subtype, the overall degree of intra-tumoral infiltrating immune cells was low. In the TP53 mutant subtype, the densities of both PD-L1⁺ macrophages (p = 0.047) and PD-1⁺ T cells (p = 0.034) in tumor parenchyma were the highest among the four subtypes.

Conclusion

Endometrial cancer of TMB-H, NSMP and TP53 mutant subtypes displayed phenotypes of normal immune response, absence of immune infiltration, and suppressed immune response, respectively. These features may provide mechanistic explanations for the differences in patients' prognosis and efficacy of immune checkpoint blockade therapies among different endometrial cancer subtypes.

Molecular-Targeted Therapy for Tumor-Agnostic Mutations in Acute Myeloid Leukemia

Comprehensive genomic profiling examinations (CGPs) have recently been developed, and a variety of tumor-agnostic mutations have been detected, leading to the development of new molecular-targetable therapies across solid tumors. In addition, the elucidation of hereditary tumors, such as breast and ovarian cancer, has pioneered a new age marked by the development of new treatments and lifetime management strategies required for patients with potential or presented hereditary cancers. In acute myeloid leukemia (AML), however, few tumor-agnostic or hereditary mutations have been the focus of investigation, with associated molecular-targeted therapies remaining poorly developed. We focused on representative tumor-agnostic mutations such as the TP53, KIT, KRAS, BRCA1, ATM, JAK2, NTRK3, FGFR3 and EGFR genes, referring to a CGP study conducted in Japan, and we considered the possibility of developing molecular-targeted therapies for AML with tumor-agnostic mutations. We summarized the frequency, the prognosis, the structure and the function of these mutations as well as the current treatment strategies in solid tumors, revealed the genetical relationships between solid tumors and AML and developed tumor-agnostic molecular-targeted therapies and lifetime management strategies in AML.

“Iron triangle” of regulating the uterine microecology: Endometrial microbiota, immunity and endometrium

The uterus is the core place for breeding new life. The balance and imbalance of uterine microecology can directly affect or even dominate the female reproductive health. Emerging data demonstrate that endometrial microbiota, endometrium and immunity play an irreplaceable role in regulating uterine microecology, forming a dynamic iron triangle relationship. Up to nowadays, it remains unclear how the three factors affect and interact with each other, which is also a frontier topic in the emerging field of reproductive tract microecology. From this new perspective, we aim to clarify the relationship and mechanism of the interaction of these three factors, especially their pairwise interactions. Finally, the limitations and future perspectives of the current studies are summarized. In general, these three factors have a dynamic relationship of mutual dependence, promotion and restriction under the physiological or pathological conditions of uterus, among which the regulatory mechanism of microbiota and immunity plays a role of bridge. These findings can provide new insights and measures for the regulation of uterine microecology, the prevention and treatment of endometrial diseases, and the further multi-disciplinary integration between microbiology, immunology and reproductive medicine.

Programmed cell death-1 inhibitor combination treatment for recurrent proficient mismatch repair/ miscrosatellite-stable type endometrial cancer: A case report

BACKGROUND

Endometrial cancer (EC) is one of the most common cancers of the female reproductive tract, and the incidence is increasing rapidly. Immunotherapy using programmed cell death-1 (PD-1) inhibitors is an emerging research topic and treatment strategy for refractory gynecological malignancies. However, clinical management of EC with checkpoint inhibitors requires improvement. Herein, we discuss a case of refractory proficient mismatch repair (pMMR)/miscrosatellite-stable (MSS) EC treated with a combination of PD-1 and angiogenesis inhibitors and offer a review of the pathophysiology and clinical outcomes based on previous studies.

CASE SUMMARY

A 62-year-old woman diagnosed with invasive or metastatic EC in 2015 was treated with six courses of chemotherapy and refused further radiotherapy. Four years later, she developed chest pain, and lung biopsy indicated thyroid transcription factor-1 (-), Napsin A (-), estrogen receptor (+), progesterone receptor (+), anaplastic lymphoma kinase (D5F3) (-), and receptor tyrosine kinase (D4D6) (-) metastatic EC. Genetic testing results showed low tumor mutation burden, pMMR, PD ligand 1 (-), MSS, and HLA-class 1 heterogeneous disease. The patient was started on toripalimab combined with nab-paclitaxel for seven cycles (every 3 wk), but this regimen was terminated because of an intolerable chemotherapy adverse event. The disease progressed in 2020, and the patient’s treatment was switched from nab-paclitaxel to anlotinib, while immunotherapy using toripalimab was continued. The patient achieved a major partial response with well-tolerated toxicities, and treatment is ongoing.

CONCLUSION

Molecular testing is advised for clinical classifications of EC owing to its high heterogeneity. In this case, the patient had pMMR/MSS EC and achieved a positive outcome with combination PD-1 inhibitor treatment. These results warrant further clinical exploration.

Integrated Bioinformatics Analysis of Serine Racemase as an Independent Prognostic Biomarker in Endometrial Cancer

Endometrial cancer (EC) kills about 76,000 women worldwide, with the highest incidence in industrialized countries. Because of the rise in disease mortality and new diagnoses, EC is now a top priority for women’s health. Serine racemase (SRR) is thought to play a role in the central nervous system, but its role in cancers, particularly in EC, is largely unknown. The current study starts with a pan-cancer examination of SRR’s expression and prognostic value before delving into SRR’s potential cancer-suppressing effect in patients with EC. SRR may affect the endometrial tumor immune microenvironment, according to subsequent immune-related analysis. SRR expression is also linked to several genes involved in specific pathways such as ferroptosis, N6-methyladenosine methylation, and DNA damage repair. Finally, we used the expression, correlation, and survival analyses to investigate the upstream potential regulatory non-coding RNAs of SRR. Overall, our findings highlight the prognostic significance of SRR in patients with EC, and we can formulate a reasonable hypothesis that SRR influences metabolism and obstructs key carcinogenic processes in EC.

Diagnosis and Prediction of Endometrial Carcinoma Using Machine Learning and Artificial Neural Networks Based on Public Databases

Endometrial carcinoma (EC), a common female reproductive system malignant tumor, affects thousands of people with high morbidity and mortality worldwide. This study was aimed at developing a prediction model for the diagnosis of EC in the general population. First, we obtained datasets GSE63678, GSE106191, and GSE115810 from the Gene Expression Omnibus (GEO) database, dataset GSE17025 from the GEO database, and the RNA sequence of EC from The Cancer Genome Atlas (TCGA) database to constitute the training, test, and validation groups, respectively. Subsequently, the 96 most significantly differentially expressed genes (DEGs) were identified and analyzed for function and pathway enrichment in the training group. Next, we acquired the disease-specific genes by random forest and established an artificial neural network for the diagnosis. Receiver operating characteristic (ROC) curves were utilized to identify the signature across the three groups. Finally, immune infiltration was analyzed to reveal tumor-immune microenvironment (TIME) alterations in EC. The top 96 DEGs (77 down-regulated and 19 up-regulated genes) were primarily enriched in the interleukin-17 signaling pathway, protein digestion and absorption, and transcriptional misregulation in cancer. Subsequently, 14 characterizing genes of EC were identified by random forest. In the training, test, and validation groups, the artificial neural network was constructed with high diagnostic accuracies of 0.882, 0.864, and 0.839, respectively, and areas under the ROC curve (AUCs) of 0.928, 0.921, and 0.782, respectively. Finally, resting and activated mast cells were found to have increased in TIME. We constructed an artificial diagnostic model with excellent reliability for EC and uncovered variations in the immunological ecosystem of EC through integrated bioinformatics approaches, which might be potential diagnostic targets for EC.

Microsatellite instability and chemosensitivity in solid tumours

The use of biomarkers that influence a targeted choice in cancer treatments is the future of medical oncology. Within this scenario, in recent years, an important role has been played by knowledge of microsatellite instability (MSI), a molecular fingerprint that identifies defects in the mismatch repair system. This knowledge has changed clinical practice in the adjuvant setting of colon cancer, and its role in the neoadjuvant setting in gastric tumours is becoming increasingly interesting, as well as in endometrial cancers in both early and advanced diseases. Furthermore, it has undoubtedly conditioned the first lines of treatment in the metastatic setting in different types of cancers. The incidence of MSI is different in different cancer types, as well as in early cancers versus metastatic disease. Knowing the incidence of MSI in the various histologies can provide insight into the potential use of this biomarker considering its prognostic value, especially in the early stages, and its predictive role with respect to treatment response. In particular, MSI can guide the choice of chemotherapy treatments in the adjuvant setting of colon and perioperative setting in gastric tumours, which could lead to immunotherapy treatments in these patients in both the early stages of the disease and the metastatic setting where the response to immunotherapy drugs in diseases with MSI is now well established. In this review, we focus on colon, gastric and endometrial cancers, and we briefly discuss other cancer types where MSI could have a potential role in oncological treatment decisions.

Comprehensive Analysis of DNA Methylation and Transcriptome to Identify PD-1-Negative Prognostic Methylated Signature in Endometrial Carcinoma

Background

Epigenetic mechanism plays an important role in endometrial carcinoma (EC). This study was designed to analyze the epigenetic mechanism between DNA methylation-driven genes (DEDGs) and drugs targeting DEDGs and to develop a DEDG score model for predicting the prognosis of EC.

Methods

Expression profile and methylation profile data of PD-1-negative EC samples were obtained from TCGA. To obtain intersected DEDGs, differentially expressed genes (DEGs) and differentially methylated genes from tumor tissues and normal tissues were analyzed by limma. A linear discriminant classification model was constructed using the gene expression profile of DMDGs, methylation profile of TSS1500, TSS200, and gene body regions. Principal component analysis (PCA) and ROC analysis were conducted. The protein-drug interactions analysis of DMDGs was performed using Network Analyst 3.0 tool. Lasso Cox regression analysis was used to screen prognostic DNA methylation driving gene and to build a risk score model. The ROC curve and Kaplan-Meier survival curve were plotted to evaluate the model prediction capability.

Results

A total of 96 DMDGs were screened from the three regions, distributed on 22 chromosomes, with consistent methylation patterns in different gene regions. Both the expression profile and methylation profile of the three regions can neatly distinguish tumor samples from normal ones, with a high classifying performance. A gene signature, which consisted of ELFN1-AS1 and ZNF132, could classify EC patients into a high-risk group and low-risk group. Prognosis of the high-risk group was significantly worse than that of the low-risk group. The risk model showed a high performance in predicting the prognosis of EC.

Conclusion

We successfully established a risk score system with two DMDGs, which showed a high prediction accuracy of EC prognosis.

The Two-Faced Role of Autophagy in Endometrial Cancer

Autophagy, meaning “self-eating,” is a cellular catabolic process that involves lysosomal degradation of cytoplasmic materials. Autophagy contributes to both quality control and energy supply of cells, which are associated with tumorigenesis and tumor development, respectively. Endometrial cancer (EC) is the most common gynecologic cancer, and its incidence is increasing. Although autophagy plays crucial roles in several types of cancer, such as pancreatic ductal adenocarcinoma, its role in EC has not been clearly demonstrated. Activation of the PI3K/AKT/mTOR pathway, which functions to suppress autophagy, is an initial step in type 1 endometrial carcinogenesis, whereas a loss-of-function mutation of TP53, which augments autophagy via p16 induction, is the main cause of type 2 endometrial carcinogenesis. Mutations in autophagy-related genes, including ATG4C, RB1CC1/FIP200, and ULK4, have been reported in EC; thus, an aberrant autophagy mechanism may be involved in endometrial carcinogenesis. Furthermore, the biguanide diabetes drug metformin, treatment with which enhances autophagy via AMPK-mediated mTOR inactivation, has been reported to reduce the risk of EC. These findings suggest that autophagy negatively regulates endometrial carcinogenesis, and autophagy inducers may be useful for chemoprevention of EC. In contrast, autophagy appears to promote EC once it is established. Consistent with this, treatment with chloroquine, an autophagy inhibitor, is reported to attenuate EC cell proliferation. Moreover, chemotherapy-induced autophagy triggers chemoresistance in EC cells. As autophagy has a tumor-promoting function, the combination of chemotherapy and autophagy inhibitors such as chloroquine could be a potent therapeutic option for patients with EC. In conclusion, autophagy plays a dual role in the prevention and treatment of EC. Therefore, targeting autophagy to prevent and treat EC requires diametrically opposed strategies.

Mismatch repair and clinical response to immune checkpoint inhibitors in endometrial cancer

Endometrial cancer is common, and a subset recurs and requires additional treatment.

Some of these are recognized as being susceptible to immune therapies and are said to have mismatch repair deficiency (dMMR).

However, this clinical trial highlights which cases are more likely to respond well: those containing mutations in genes known as Lynch genes and also some with mutations in POLE/POLD1 (“ultra‐hypermutation” genes).

In contrast, the majority of dMMR endometrial cancers have silencing or DNA methylation of one of these genes, MLH1, and do not seem to be as responsive to single‐agent immune therapy.

The availability of combination therapies may be important to consider for these women.

This hypothesis‐driving study highlights the need for further evaluation of the interaction between immune checkpoint inhibitor therapy responses and the mechanism of DNA mismatch repair (MMR) deficiency. Although MMR gene germline pathogenic variant carriers and Lynch‐like tumors with double somatic MMR gene mutations are highly likely to respond to a single‐agent immune checkpoint inhibitor (ICI), those with MLH1 hypermethylation may benefit from additional agents to induce an ICI response.

High PD-L1 Expression on Tumor Cells Indicates Worse Overall Survival in Advanced Oral Squamous Cell Carcinomas of the Tongue and the Floor of the Mouth but Not in Other Oral Compartments

The markers of the tumor microenvironment (TME) are promising prognostic and predictive factors in oral squamous cell carcinoma (OSCC). The current study aims to analyze the immunohistochemical expression of programmed cell death-ligand 1 (PD-L1) and interleukin-33 (IL-33) in a cohort of 95 chemonaïve OSCCs. PD-L1 and IL-33 were assessed separately in tumor cells (TCs) and tumor-infiltrating lymphocytes (TILs). High PD-L1 expression in TILs was associated with better overall survival (OS) in univariate analysis. Tumors localized in the floor of the oral cavity and tongue tended to have a lower percentage of PD-L1-positive TCs when compared to other locations. PD-L1 expression on TCs had no prognostic significance when the whole cohort was analyzed. However, along with the T descriptor (TNM 8th), it was included in the multivariable model predicting death in carcinomas of the floor of the oral cavity and tongue (HR = 2.51, 95% CI = 1.97-5.28). In other locations, only nodal status was identified as an independent prognostic factor in multivariate analysis (HR = 0.24, 95% CI = 0.08-0.70). Expression of IL-33 had no impact on survival, but it was differently expressed in various locations. In conclusion, the prognostic significance of PD-L1 in oral cancer depends on the tumor site and type of cell expressing immune checkpoint receptor (TCs vs. TILs).

Discordant immunohistochemistry in an unusual MLH1 gene variant in a case of Lynch syndrome

Immunohistochemistry for mismatch repair proteins and microsatellite instability testing are recommended screening methods for Lynch syndrome. They have a good sensitivity and specificity, allowing for directed genetic testing and diagnosis. We report a case of Lynch syndrome with retained MMR protein expression who later showed an MLH1 gene variant on genetic testing (Next Generation Sequencing) requested because of the clinical presentation of metachronous colonic and endometrial carcinoma. This report makes the case for strong clinical suspicion and directed genetic testing despite initial screen negative results.