POLE Mutation Characteristics in a Chinese Cohort with Endometrial Carcinoma

The prognostic implication of polymerase epsilon-mutated endometrial cancer

The traditional classification and risk stratification systems of endometrial cancer (EC), which relied on histomorphological features, were limited and poor reproducible. The classification of new molecular subtypes of EC has been developing, including The Cancer Genome Atlas (TCGA)-four molecular subtypes: Polymerase epsilon (POLE) mutation (POLEmut), microsatellite instability hypermutated, copy number-low, and copy number-high and ProMisE-four molecular subtypes: POLEmut, mismatch repair deficiency, no specific molecular profile, and p53 abnormal. POLEmut usually correlates with a favorable outcome. Hence, we reviewed the research since the TCGA molecular subtypes developed in 2013 and summarized the characteristics and prognosis of POLEmut EC patients. In summary, we found POLEmut occurs in 7.3%-9.6% of EC in the previous studies. POLEmut EC consistently exhibits favorable patient outcomes, regardless of adjuvant therapy. The research of POLEmut in EC is absent in Taiwan, and the underlying mechanisms and cost-effectiveness need further investigation.

Unveiling immunogenic characteristics and neoantigens in endometrial cancer with POLE hotspot mutations for improved immunotherapy

Background

Immunotherapy, especially with the use of immune checkpoint inhibitors, has demonstrated efficacy for a variety of malignant tumors. However, the potential of immunotherapy for endometrial cancer (EC) with POLE mutations remains underexplored.

Methods

We utilized multiple databases and clinical specimens to investigate the immunogenicity profiles of EC patients carrying POLE mutations. One particular hotspot mutation POLEP286R was identified and further studied. Consequently, by constructing human leukocyte antigen (HLA) tetramers and incubating them with patients' peripheral blood mononuclear cells (PBMCs), T cells capable of recognizing the POLEP286R mutation were sorted for further transcriptomic, proteomic and T-cell receptor (TCR) sequencing analyses and for an organoid EC model.

Results

Tumor- and immune-related pathways were shown to be activated in the POLEP286R mutant group. Importantly, by using an organoid model of EC, we further confirmed the antitumor potential of T cells that were specific to the POLEP286R mutation.

Conclusions

Our study uncovers the pronounced immunogenicity of POLE-mutant EC and characterizes neoantigens that are unique to the POLEP286R mutation, thus providing a promising new immunotherapeutic strategy for EC.

Identification and validation of glucose metabolism-related gene signature in endometrial cancer

BACKGROUND

Metabolic syndrome associated with glucose metabolism plays a pivotal role in tumorigenesis, potentially elevating the risk of endometrial cancer (EC). This study sought to establish a glucose metabolism-related gene (GMRG) signature linked to EC.

METHODS

Differential analysis was conducted to identify differentially expressed genes (DEGs) between EC and normal samples from the TCGA-EC dataset. Glucose metabolism-related DEGs (GMR-DEGs) were then derived by intersecting these DEGs with GMRGs. A prognostic signature for EC was developed through the Least Absolute Shrinkage and Selection Operator (LASSO) regression and univariate Cox analysis. Additionally, immune profiling and immunotherapy responsiveness were evaluated across two distinct risk subgroups, accompanied by a single-cell analysis of prognostic genes. The expression levels of these prognostic genes were quantified at both transcriptional and translational stages using reverse transcription quantitative PCR (RT-qPCR) and immunohistochemistry (IHC) in clinical samples. Furthermore, the functional significance of key genes was explored through in vitro assays.

RESULTS

2,912 DEGs and 202 GMR-DEGs were identified between the EC and normal groups. Subsequently, six prognostic genes were derived, including ASRGL1, SLC38A3, SLC2A1, ALDH1B1, GAD1, and GLYATL1. EC patients were classified into high and low-risk subgroups based on the six genes. Independent prognostic analysis indicated that risk score and disease stage were significant independent prognostic factors. Single-cell analysis revealed that the six prognostic genes were highly expressed in ciliated and epithelial cells. Immune cell infiltration was generally lower in the high-risk group, where tumor purity was elevated. The expression levels of SLC38A3, SLC2A1, and ASRGL1 are higher in tumor samples by RT-qPCR, with IHC confirming increased SLC38A3 expression. Finally, SLC38A3 may function as oncogenes in EC, as revealed by the results of in vitro experiments.

CONCLUSIONS

In this study, we developed six novel prognostic genes in EC based on glycolysis, and corresponding prognostic models were developed. Notably, we identified SLC38A3 as the key gene, which offers valuable insights for further research into EC.

High prevalence of "non-pathogenic" POLE mutation with poor prognosis in a cohort of endometrial cancer from South India

OBJECTIVE

The Cancer Genome Atlas (TCGA) project identified favorable prognosis regarding the ultra-mutated endometrial cancer (EC) subtype linked to polymerase epsilon gene (POLE) mutations. This study investigated POLE mutations in EC of Indian patients.

METHODS

This retrospective analytical study was conducted between January 2016 and January 2023 at the Government Medical College, Kozhikode, and the MVR Cancer Center, Kozhikode, Kerala. Sanger sequencing of POLE gene exons 9 and 13 in 151 EC patients was carried out to analyze the relationship between mutations and epidemiological factors, clinicopathologic features, and treatment outcomes.

RESULTS

Among 151 cases enrolled, 39 were unique POLE-mutated cases. Significant associations were high-grade tumors, myometrial invasion >50%, and Lymph-vascular space invasion (LVSI). The median follow-up was 40 months (95% confidence interval [CI], 34-46). A lower mean disease-specific survival (DSS) of 51.7 months (95% CI, 43.7-59.6) was noted in the POLE-mutated group compared with 72.11 months (95% CI, 67.60-76.62) for the POLE wild-type. A statistically significant hazard ratio (HR) of 2.683 for DSS in the POLE-mutated group was noted. In advanced stages (FIGO stages II-IV), a nine-fold HR for DSS and overall survival (OS) compared with POLE wild-type was identified. After controlling for treatment effects using Cox proportional HR, advanced-stage POLE-mutated tumors had a significantly higher HR of 8.67 for DSS compared with POLE-wild-type tumors of the same stage.

CONCLUSION

This study identified a unique set of POLE mutations in Indian EC patients associated with poor prognosis, which were particularly pronounced in advanced stages. Advanced stage of presentation, type of POLE mutations, and possibly ethnicity are predictors of adverse outcomes in POLE-mutated EC. The present study highlights ethnicity as a determinant of phenotypic expression of genetic change.

Molecular subtypes of endometrial cancer: Implications for adjuvant treatment strategies

BACKGROUND

When determining adjuvant treatment for endometrial cancer, the decision typically relies on factors such as cancer stage, histologic grade, subtype, and a few histopathologic markers. The Cancer Genome Atlas revealed molecular subtyping of endometrial cancer, which can provide more accurate prognostic information and guide personalized treatment plans.

OBJECTIVE

To summarize the expression and molecular basis of the main biomarkers of endometrial cancer.

SEARCH STRATEGY

PubMed was searched from January 2000 to March 2023.

SELECTION CRITERIA

Studies evaluating molecular subtypes of endometrial cancer and implications for adjuvant treatment strategies.

DATA COLLECTION AND ANALYSIS

Three authors independently performed a comprehensive literature search, collected and extracted data, and assessed the methodological quality of the included studies.

MAIN RESULTS

We summarized the molecular subtyping of endometrial cancer, including mismatch repair deficient, high microsatellite instability, polymerase epsilon (POLE) exonuclease domain mutated, TP53 gene mutation, and non-specific molecular spectrum. We also summarized planned and ongoing clinical trials and common therapy methods in endometrial cancer. POLE mutated endometrial cancer consistently exhibits favorable patient outcomes, regardless of adjuvant therapy. Genomic similarities between p53 abnormality endometrial cancer and high-grade serous ovarian cancer suggested possible overlapping treatment strategies. High levels of immune checkpoint molecules, such as programmed cell death 1 and programmed cell death 1 ligand 1 can counterbalance mismatch repair deficient endometrial cancer immune phenotype. Hormonal treatment is an appealing option for high-risk non-specific molecular spectrum endometrial cancers, which are typically endometrioid and hormone receptor positive. Combining clinical and pathologic characteristics to guide treatment decisions for patients, including concurrent radiochemotherapy, chemotherapy, inhibitor therapy, endocrine therapy, and immunotherapy, might improve the management of endometrial cancer and provide more effective treatment options for patients.

CONCLUSIONS

We have characterized the molecular subtypes of endometrial cancer and discuss their value in terms of a patient-tailored therapy in order to prevent significant under- or overtreatment.

Immune signatures of the POLE mutation in endometrial carcinomas: a systematic study based on TCGA data and clinical cohort validation

Background

POLE is a critical biomarker for endometrial cancer (ECs) prognosis and therapeutic decision. However, the immune infiltration and immunotherapy-related gene expression in the tumor microenvironment (TME) of POLE-mutated ECs remain unresolved.

Methods

The TCGA database was used to characterize the TME of POLE mutants, which primarily included immune cells and co-expression genes. We used immunohistochemistry (IHC) to determine immune cell abundance and PD-L1 expression in 104 EC tissues, including 11 POLE mutants and 93 wild-type.

Results

The bioinformatic study found significant differences in gene expression of the chemokine family, immune-cell markers, and lysozyme in POLE mutants, along with immune response activation. In POLE-mutated ECs, the abundance of CD4+T, CD8+T, M1 macrophages, and dendritic cells increased considerably. Furthermore, POLE mutations may enhance immune cell recruitment or activation and lymphocyte homing in ECs. POLE mutants also had increased expression of immune-checkpoint suppressor genes such as PD-L1, CTLA-4, TIM-3, and others. The tumor mutation burden (TMB) was higher in ECs with POLE mutation. In the validation cohort, we discovered that POLE mutations were related to the immune infiltration abundance of CD8+, CD4+, and Foxp3+ cells and PD-L1 expression by IHC. The prognosis of TCGA-ECs showed that the survival time of the CD8, CD4, PD-L1, or Foxp3 over-expression subgroup of the POLE mutants was significantly prolonged compared to the down-regulation subgroup or the POLE wild-type.

Conclusion

The infiltration abundance of CD8+ T, CD4+ T, Foxp3+ T cells, and the expression of PD-L1 harbor crucial value for the prognosis or individualized therapy of POLE-mutated ECs.

A novel somatic mutation in POLE exonuclease domain associated with ultra-mutational signature and MMR deficiency in endometrial cancer: a case report

BACKGROUND

Defect in proofreading exonuclease activity of polymerases epsilon and delta (Pols ε and δ) leads to mutagenesis and genomic instability and has been described in several cancer types. Somatic POLE exonuclease domain mutations (EDMs) have been reported in 7-12% endometrial cancers (ECs) and defined a subgroup of endometrial cancers with ultrahigh somatic mutation frequencies, high tumor infiltrated lymphocytes and favorable outcomes.

CASE PRESENTATION

Herein, we presented a novel somatic mutation in POLE exonuclease domain associated with ultra-mutational signature and MMR deficiency in endometrial cancer. A novel POLE EDM (p.T278K) was found by a 11-gene NGS panel. The MSS status detected by the MSI test was inconsistent with the dMMR status by IHC. The loss of MSH6 expression in the tumor could be interpreted by the two nonsense mutations (p.E1234* and p.E1322*) of the MSH6 gene which may lead to truncated proteins. The T278K mutation was pathogenic identified by a 602-gene NGS panel with 27.3% of C > A substitution, 0.6% of indels, 0.6% of C > G substitution and a high TMB of 203.8 mut/Mb.

CONCLUSIONS

We report an endometrial cancer patient harbored a novel somatic POLE T278K mutation. This mutation was a novel pathogenic POLE EDM should be considered as "POLE (ultramutated)" in clinical practice for the molecular classification of EC.

Injection rate of contrast medium affects diagnostic ability of dynamic contrast-enhanced magnetic resonance imaging for endometrial carcinoma: a prospective cohort study

Background

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) can obtain semi-quantitative or quantitative parameters of tumors by capturing the images before and after injection of contrast medium. However, there has been no further research on the effect of flow rate of contrast medium on image quality and parameter sensitivity of DCE-MRI in endometrial carcinoma (EC).

Methods

This was a prospective cohort study enrolling patients who were suspected of EC between January 2018 and June 2020. The baseline data of participants were collected. Post-surgical histological examination acted as the gold standard of EC diagnosis and some characteristics of tumors were recorded. We calculated 3 important parameters of DCE-MRI, including volume transfer constant (K^trans), flux rate constant (K_ep), and extravascular extracellular volume fraction (V_e), according to the MRI system. The image quality in DCE-MRI imaging was evaluated according to contrast, resolution, artifact, signal-to-noise ratio, and scanning time. To evaluate the diagnostic ability of DCE-MRI with different injection rate, receiver operating characteristic (ROC) curve was generated and the area under curve (AUC) was calculated.

Results

According to the different injection rate of contrast medium, participants were divided into three groups, including 2, 3, and 4 mL/s group. It was found that there were more grade 1 EC in the 3 mL/s group (52.4%) than other two groups (34.3% and 23.3%, respectively), and the difference was significant (P=0.021). No other significant differences were found among all other variables. It was found that K^trans was much higher in the 4 mL/s group than in other two groups (P<0.001). Also, V_e was much higher in the 4 mL/s group than in other two groups (P<0.001). However, no significant difference was found in K_ep between three groups (P=0.633). Besides, the 4 mL/s group had the highest quality of all three groups (P<0.001). The sensitivity, specificity, and accuracy were highest in 4 mL/s group. The AUC in three groups were 0.822, 0.832, and 0.888 in the 2, 3, and 4 mL/s group, respectively.

Conclusions

The DCE-MRI measurement is useful for the diagnosis of EC, and faster injection rate may be beneficial to improve diagnostic accuracy and image quality.