Tumor genotype and immune microenvironment in POLE-ultramutated and MSI-hypermutated Endometrial Cancers: New candidates for checkpoint blockade immunotherapy?

MITO END-3: efficacy of avelumab immunotherapy according to molecular profiling in first-line endometrial cancer therapy

BACKGROUND

Immunotherapy combined with chemotherapy significantly improves progression-free survival (PFS) compared to first-line chemotherapy alone in advanced endometrial cancer (EC), with a much larger effect size in microsatellite instability-high (MSI-H) cases. New biomarkers might help to select patients who may have benefit among those with a microsatellite-stable (MSS) tumor.

PATIENTS AND METHODS

In a pre-planned translational analysis of the MITO END-3 trial, we assessed the significance of genomic abnormalities in patients randomized to standard carboplatin/paclitaxel without or with avelumab.

RESULTS

Out of 125 randomized patients, 109 had samples eligible for next-generation sequencing analysis, and 102 had MSI tested. According to The Cancer Genome Atlas (TCGA), there were 29 cases with MSI-H, 26 with MSS TP53 wild type (wt), 47 with MSS TP53 mutated (mut), and 1 case with POLE mutation. Four mutated genes were present in >30% of cases: TP53, PIK3CA, ARID1A, and PTEN. Eleven patients (10%) had a BRCA1/2 mutation (five in MSI-H and six in MSS). High tumor mutational burden (≥10 muts/Mb) was observed in all MSI-H patients, in 4 out of 47 MSS/TP53 mut, and no case in the MSS/TP53 wt category. The effect of avelumab on PFS significantly varied according to TCGA categories, being favorable in MSI-H and worst in MSS/TP53 mut (P interaction = 0.003); a similar non-significant trend was seen in survival analysis. ARID1A and PTEN also showed a statistically significant interaction with treatment effect, which was better in the presence of the mutation (ARID1A P interaction = 0.01; PTEN P interaction = 0.002).

CONCLUSION

The MITO END-3 trial results suggest that TP53 mutation is associated with a poor effect of avelumab, while mutations of PTEN and ARID1A are related to a positive effect of the drug in patients with advanced EC.

Special Considerations in Classification and Workup of Endometrial Carcinomas

CONTEXT.—

A variety of uncommon malignant endometrial tumors can be challenging to diagnose because of overlapping morphology with more common entities. In some cases, immunohistochemical stains and/or molecular testing allow for more definitive diagnosis or prognostication.

OBJECTIVE.—

To review classic morphologic features of uncommon endometrial tumors, pathologic features of these tumors and their mimics, and the evidence for use of immunohistochemistry and molecular testing in the diagnosis of these tumors.

DATA SOURCES.—

University of Michigan (Ann Arbor) cases and review of pertinent literature about each entity.

CONCLUSIONS.—

Although each of these uncommon endometrial tumors has morphologic mimics, key histologic features, immunohistochemical stains, and molecular testing allow for accurate classification.

TIGIT: A potential immunotherapy target for gynecological cancers

Gynecological cancer represents a significant global health challenge, and conventional treatment modalities have demonstrated limited efficacy. However, recent investigations into immune checkpoint pathways have unveiled promising opportunities for enhancing the prognosis of patients with cancer. Among these pathways, TIGIT has surfaced as a compelling candidate owing to its capacity to augment the immune function of NK and T cells through blockade, thereby yielding improved anti-tumor effects and prolonged patient survival. Global clinical trials exploring TIGIT blockade therapy have yielded promising preliminary findings. Nevertheless, further research is imperative to comprehensively grasp the potential of TIGIT-based immunotherapy in optimizing therapeutic outcomes for gynecological cancers. This review primarily delineates the regulatory network and immunosuppressive mechanism of TIGIT, expounds upon its expression and therapeutic potential in three major gynecological cancers, and synthesizes the clinical trials of TIGIT-based cancer immunotherapy. Such insights aim to furnish novel perspectives and serve as reference points for subsequent research and clinical application targeting TIGIT in gynecological cancers.

It is time to implement molecular classification in endometrial cancer

A huge effort has been done in redefining endometrial cancer (EC) risk classes in the last decade. However, known prognostic factors (FIGO staging and grading, biomolecular classification and ESMO-ESGO-ESTRO risk classes stratification) are not able to predict outcomes and especially recurrences. Biomolecular classification has helped in re-classifying patients for a more appropriate adjuvant treatment and clinical studies suggest that currently used molecular classification improves the risk assessment of women with EC, however, it does not clearly explain differences in recurrence profiles. Furthermore, a lack of evidence appears in EC guidelines. Here, we summarize the main concepts why molecular classification is not enough in the management of endometrial cancer, by highlighting some promising innovative examples in scientific literature studies with a clinical potential significant impact.

Targeting TCF19 sensitizes MSI endometrial cancer to anti-PD-1 therapy by alleviating CD8+ T cell exhaustion via TRIM14-IFN-β axis

Immune checkpoint blockade (ICB) therapies display clinical efficacy in microsatellite instable (MSI) endometrial cancer (EC) treatment, the key mechanism of which is reversing T cell exhaustion and restoration of anti-tumor immunity. Here, we demonstrate that transcription factor 19 (TCF19), one of the most significantly differentially expressed genes between MSI and microsatellite stable (MSS) patients in The Cancer Genome Atlas (TCGA)-EC cohort, is associated with poor prognosis and immune exhaustion signature. Specifically, TCF19 is significantly elevated in MSI EC, which in turn promotes tripartite motif-containing 14 (TRIM14) transcription and correlates with hyperactive signaling of the TANK-binding kinase 1 (TBK1)-interferon regulatory factor 3 (IRF3)-interferon β (IFN-β) pathway. The TCF19-TRIM14 axis promotes tumorigenicity under non-immunological background, and the enhanced downstream secretion of IFN-β facilitates CD8+ T cell exhaustion through cell differentiation reprogramming. Finally, using humanized models, we show that a combination of TCF19 inhibition and ICB therapy demonstrates more effective anti-tumor responses. Together, our study indicates that targeting TCF19 is a potent strategy for alleviating CD8+ T cell exhaustion and synergizing with ICB in tumor treatment.

The role of TCGA molecular classification in clear cell endometrial carcinoma

Clear cell endometrial carcinoma (CCEC) represents a relatively rare and heterogeneous entity. Based on The Cancer Genome Atlas (TCGA) molecular classification, the risk stratification and management of endometrial cancer (EC) have been improved. Although the relationship of CCEC with the TCGA classification is less well understood, data has emerged to suggest that molecular classification plays an important role in the prognosis and management of CCEC. Most of patients with CCEC are characterized by p53abn or NSMP type and the prognosis of these patients is poor, whereas those with MMRd or POLEmut seem to have a favorable prognosis. Adjuvant therapy is recommended in CCEC with p53abn and NSMP. Advanced/recurrent CCEC with MMRd benefit much more from immune checkpoint inhibitors after the failure of platinum-based chemotherapy. In addition, bevacizumab plus chemotherapy upfront seems to improve outcomes of advanced/recurrent patients whose tumors harbored mutated TP53, including CCECs with p53abn. Further studies which exclusively recruit CCEC are urgently needed to better understand the role of molecular classification in CCEC. This review will provide an overview of our current understanding of TCGA classification in CCEC.

Tumor Microenvironment CD8 T and Treg Cells-related Genes Signature Distinguishes Distinct Prognosis and Targeted Therapies Response in Endometrial Cancer

Although most endometrial cancer (EC) patients have a favorable prognosis, the overall survival (OS) of metastatic and recurrent EC could hardly be improved by the current chemoradiotherapy. We aimed to reveal the tumor microenvironment immune infiltration characteristics to elucidate the underlying mechanism of EC progression and guide clinical decisions. In the Cancer Genome Atlas (TCGA) cohort, Kaplan-Meier survival curves confirmed Tregs and CD8 T cells were prognosis-protective factors in OS of EC ( P <0.05). Weighted gene coexpression network analysis identified 2 gene modules closely correlated with Tregs and CD8 T-cell infiltration. We randomly split the TCGA EC cohort into the training and testing cohorts at a ratio of 7:3. An immune-related prognosis risk index (IRPRI), including NR3C1, E2F1, OTOG, TTK, PPP1R16B, and FOXP3, was established by univariate, Least Absolute Shrinkage and Selection Operator, and multivariate Cox regression with area under the curve >0.67. Distinct clinical, immune, and mutation characteristics existed between IRPRI groups by multiomics analysis. Cell proliferation and DNA damage repair-related pathways were activated, and immune-related pathways were inactivated in the IRPRI-high group. Furthermore, patients in the IRPRI-high group had lower tumor mutation burden, programmed death-ligand 1 expression, and Tumor Immune Dysfunction and Exclusion scores, indicating a poor response to immune checkpoint inhibitors therapy ( P <0.05), which was also validated in the TCGA testing cohort and independent cohorts, GSE78200, GSE115821, and GSE168204. Also, the higher mutation frequencies of BRCA1, BRCA2, and genes enrolled in homologous recombination repair in the IRPRI-low group predicted a good response to PARP inhibitors. Finally, a nomogram integrating the IRPRI group and prognosis significant clinicopathological factors for EC OS prediction was developed and validated with good discrimination and calibration.

Advances in the application of immune checkpoint inhibitors in gynecological tumors

BACKGROUND

Immune checkpoints are regulatory molecules that suppress immune effector cells, and are essential for maintaining tolerance, preventing autoimmune reactions, and minimizing tissue damage by controlling the duration and intensity of the immune responses. However, immune checkpoints are frequently upregulated during cancer and dampen the anti-tumor immune responses. Immune checkpoint inhibitors (ICIs) have been effective against multiple tumors, and have improved patients' survival outcomes. Recent clinical trials have also reported promising therapeutic effects of ICIs in some gynecological cancers.

AIM

To review the current research and future directions in the treatment of gynecological malignancies, including ovarian, cervical and endometrial cancers, using ICIs.

CONCLUSION

Currently, cervical and ovarian cancers are the only gynecological tumors that are treated by immunotherapeutic approaches. In addition, ICIs, chimeric antigen receptor (CAR)- and T cell receptor (TCR)-engineered T cells targeting endometrial tumors, especially those originating in the vulva and fallopian tubes, are under development. Nevertheless, the molecular mechanism underlying the effects of ICIs, especially in combination with chemotherapy, radiation therapy, anti-angiogenesis drugs and poly ADP ribose polymerase inhibitors (PARPi), needs to be elucidated. Furthermore, novel predictive biomarkers have to be identified in order to increase the therapeutic efficacy of ICIs while reducing adverse reactions.

Identification of tumour antigens and immune subtypes in the development of an anti-cancer vaccine for endometrial carcinoma

Therapeutic application of vaccines to endometrial carcinoma (EC) remains uncertain. In this study, we aimed to identify potential tumour antigens for use in the development of an anti-tumour mRNA vaccine and clarify immune subtypes and their characteristics for immunotherapeutic application in heterogeneous EC by integrating multi-omics data. Importantly, four potential tumour antigen candidates-PGR, RBPJ, PARVG and MSX1-were identified and significantly correlated with better overall survival, disease-free survival and distinct antigen-presenting cell infiltration in EC. In addition, two different immune subtypes by consensus clustering analysis of the immune-related genes were identified. Patients with C2 immunophenotypes exhibited superior survival outcomes and 'hot' immunoreactivity and harboured higher microsatellite instability scores and tumoral mutation burden but lower copy-number variation burden. Furthermore, the distinct expression of immunogenic cell death modulators and differential microenvironmental characteristics of immune-cell infiltration were also revealed between C1 and C2 immune-subtype tumours. Enrichment analysis of the co-expression of immune-related genes showed enrichment in immune response, immune cell-mediated immunity and antigen processing pathways. These results indicated that these identified tumour antigens can be used for developing antitumour mRNA vaccines, and tumours with C2 immunophenotypic characteristics demonstrated sensitivity and susceptibility to immunotherapy in EC.

Carboplatin and paclitaxel plus avelumab compared with carboplatin and paclitaxel in advanced or recurrent endometrial cancer (MITO END-3): a multicentre, open-label, randomised, controlled, phase 2 trial

BACKGROUND

Adding immunotherapy to first-line chemotherapy might improve outcomes for patients with advanced or recurrent endometrial cancer. We aimed to compare carboplatin and paclitaxel versus avelumab plus carboplatin and paclitaxel as first-line treatment with avelumab given concurrent to chemotherapy and as maintenance after the end of chemotherapy.

METHODS

MITO END-3 is an open-label, randomised, controlled, phase 2 trial conducted at 31 cancer institutes, hospitals, and universities in Italy. Eligible patients were aged 18 years or older with histologically confirmed advanced (FIGO stage III-IV) or recurrent endometrial cancer, an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1, and no previous systemic anticancer therapy as primary treatment for advanced or metastatic disease. Participants were randomly assigned (1:1) using a computerised minimisation procedure stratified by centre, histology, and stage at study entry, to either receive carboplatin (area under the curve [AUC] 5 mg/mL × min) and paclitaxel (175 mg/m²; standard group) intravenously every 3 weeks for six to eight cycles or avelumab (10 mg/kg intravenously) added to carboplatin and paclitaxel (experimental group) every 3 weeks and then every 2 weeks as a single maintenance treatment after the end of chemotherapy until disease progression or unacceptable toxicity. Patients, treating clinicians, and those assessing radiological examinations were not masked to study treatment. The primary endpoint was investigator-assessed progression-free survival, measured in the intention-to-treat (ITT) population. Patients who received at least one dose of study drug were included in the safety analysis. Experimental group superiority was tested with 80% power and one-tailed α 0·20. This trial is registered with ClinicalTrials.gov (NCT03503786) and EudraCT (2016-004403-31).

FINDINGS

From April 9, 2018, to May 13, 2021, 166 women were assessed for eligibility and 39 were excluded. 125 eligible patients were randomly assigned to receive carboplatin and paclitaxel (n=62) or avelumab plus carboplatin and paclitaxel (n=63) and included in the ITT population. The median follow-up was 23·3 months (IQR 13·2-29·6) and was similar between the two groups. 91 progression-free survival events were reported, with 49 events in 62 patients in the standard group and 42 events in 63 patients in the experimental group. The median progression-free survival was 9·9 months (95% CI 6·7-12·1) in the standard group and 9·6 months (7·2-17·7) in the experimental group (HR of progression or death 0·78 [60% CI 0·65-0·93]; one-tailed p=0·085). Serious adverse events were reported more frequently in the experimental group (24 vs seven events in the standard group); neutrophil count decrease was the most frequent grade 3-4 adverse event (19 [31%] of 61 patients in the experimental group vs 26 [43%] of 61 patients in the standard group). Two deaths occurred in the experimental group during treatment (one respiratory failure following severe myositis [possibly related to treatment] and one cardiac arrest [not related to treatment]).

INTERPRETATION

Adding avelumab to first-line chemotherapy deserves further testing in patients with advanced or recurrent endometrial cancer, although consideration of mismatch repair status is warranted.

FUNDING

Pfizer.

Chemotherapy-free treatment of recurrent advanced ovarian cancer: myth or reality?

Advanced ovarian cancer remains a leading cause of death from gynecologic malignancy. Surgery and, in most cases, platinum-based chemotherapy with or without maintenance with bevacizumab and/or poly-ADP ribose polymerase inhibitors (PARPi) represent the mainstay of treatment, but the disease typically recurs. The treatment of these patients represents a clinical challenge because sequential chemotherapy regimens are often used, with suboptimal outcomes and cumulative toxicity. Chemotherapy-free regimens, based on combinations of PARPi, vascular endothelial growth factor receptor inhibitors, anti-programmed cell death protein-1/programmed death-ligand 1, and anti-cytotoxic T-lymphocyte-associated protein-4 antibodies, among others, represent a valid option, with manageable toxicity profile and ease of administration. This review addresses this new strategy in the management of recurrent ovarian cancer and discusses its feasibility in the treatment landscape of the disease.

Molecular Characterizations of Gynecologic Carcinosarcomas: A Focus on the Immune Microenvironment

Gynecologic carcinosarcomas, specifically of endometrial and ovarian origin, are aggressive and rare tumors. Treatment data are limited and are often extrapolated from other histologies and smaller retrospective studies. While the optimal therapy approach remains contentious, treatment is often multimodal and may include surgery, chemotherapy, radiation, or a combination of multiple strategies. However, despite aggressive treatment, these tumors fare worse than carcinomas of the same anatomic sites irrespective of their stage. Recent studies have described in-depth molecular characterizations of gynecologic carcinosarcomas. Although many molecular features mirror those seen in other uterine and ovarian epithelial tumors, the high prevalence of epithelial-mesenchymal transition is more unique. Recently, molecular descriptions have expanded to begin to characterize the tumor immune microenvironment. While the importance of the immune microenvironment has been well-established for other tumor types, it has been less systematically explored in gynecologic carcinosarcomas. Furthermore, the use of immunotherapy in patients with gynecologic carcinosarcomas has not been extensively evaluated. In this review, we summarize the available data surrounding gynecologic carcinosarcomas, with a focus on the immune microenvironment. We end with a discussion of potential immunotherapy uses and future directions for the field.

Management of Metastatic Endometrial Cancer: Physicians' Choices Beyond the First Line. A MITO Survey

Background

Endometrial cancer (EC) therapeutic and diagnostic approaches have been changed by the development of a new prognostic molecular classification, the introduction of dostarlimab in microsatellite instability (MSI) high pre-treated advanced EC patients with further expected innovation deriving from lenvatinib plus pembrolizumab regardless MSI status. How this is and will be translated and embedded in the clinical setting in Italy is not known; this is why we developed Multicentre Italian Trials in Ovarian cancer and gynaecologic malignancies (MITO) survey on the current practice and expected future changes in EC.

Methods

We designed a self-administered, multiple-choice online questionnaire available only for MITO members for one month, starting in April 2021.

Results

75.6% of the respondents were oncologists with a specific focus on gynaecologic malignancies and 73.3% of the respondents declared the availability of clinical trials in second line treatment for advanced EC. The therapeutic algorithm in second line was heterogeneous, being the most frequent choice administering anthracyclines followed by endocrine therapy or enrolling in clinical trials. While more than half of the clinicians declared that they performed the molecular classification, only six/45 respondents (13.3%) ran all the tests needed for it. On the other hand, 80% of them declared regular assessment of MSI status with IHC as recommended. The therapeutic approach in MSI high advanced EC patients has changed since dostarlimab approval. Indeed the most frequent choice in second line has been chemotherapy (53.3%) before its availability, while dostarlimab has been preferred in more than three-fourths of the cases (75.6%) after its approval. As for MSS patients, 77.8% of clinicians would choose lenvatinib plus pembrolizumab for them in second line once approved.

Conclusions

Despite the selected sample of respondents from Italian MITO centres showing good knowledge of diagnostic and therapeutic innovations in EC, these are not fully implemented in everyday clinics, except for MSI status assessment.

High-intermediate risk endometrial cancer: moving toward a molecularly based risk assessment profile

In the USA, endometrial cancer (EMCA) incidence is increasing as the risk factors of obesity, diabetes, and hypertension become more prevalent. Although most EMCA is detected at an early stage and surgical intervention is curative, a subset of patients termed 'high-intermediate risk' (H-IR) experience an increased rate of recurrence. Unfortunately, adjuvant therapies in patients with H-IR EMCA have yet to increase overall survival. Historically, stratification of these patients from their low-risk counterparts incorporated clinical and pathologic findings. However, due to developments in molecular testing and genomic sequencing, tumor biomarkers are now being incorporated into the risk-assessment criteria in the hope of finding molecular profile(s) that could highlight treatment regimens that will increase patient survival. Since modern research aims to accurately identify patients with a higher risk of recurrence and develop effective interventions to improve patient survival, these molecular-based analyses could allow for an enhanced understanding of a patient's true risk of recurrence to facilitate the rise of personalized medicine. This review summarizes key clinical trials and recent advances in molecular and genomic profiles that have influenced current treatment regimens for patients with H-IR EMCA and laid the foundation for subsequent research.

Microsatellite instability is biased in Amsterdam II-defined Lynch-related cancer cases with family history but is rare in other cancers: a summary of 1000 analyses

Background

Microsatellite instability (MSI) is a key marker for predicting the response of immune checkpoint inhibitors (ICIs) and for screening Lynch syndrome (LS).

Aim

This study aimed to see the characteristics of cancers with high level of MSI (MSI-H) in genetic medicine and precision medicine.

Methods

This study analyzed the incidence of MSI-H in 1000 cancers and compared according to several clinical and demographic factors.

Results

The incidence of MSI-H was highest in endometrial cancers (26.7%, 20/75), followed by small intestine (20%, 3/15) and colorectal cancers (CRCs)(13.7%, 64/466); the sum of these three cancers (15.6%) was significantly higher than that of other types (2.5%)(P < 0.0001). MSI-H was associated with LS-related cancers (P < 0.0001), younger age (P = 0.009), and family history, but not with smoking, drinking, or serum hepatitis virus markers. In CRC cases, MSI-H was significantly associated with a family history of LS-related cancer (P < 0.0001), Amsterdam II criteria [odds ratio (OR): 5.96], right side CRCs (OR: 4.89), and multiplicity (OR: 3.31). However, MSI-H was very rare in pancreatic (0.6%, 1/162) and biliary cancers (1.6%, 1/64) and was null in 25 familial pancreatic cancers. MSI-H was more recognized in cancers analyzed for genetic counseling (33.3%) than in those for ICI companion diagnostics (3.1%)(P < 0.0001). Even in CRCs, MSI-H was limited to 3.3% when analyzed for drug use.

Conclusions

MSI-H was predominantly recognized in LS-related cancer cases with specific family histories and younger age. MSI-H was limited to a small proportion in precision medicine especially for non-LS-related cancer cases.

KDM4B, a potential prognostic biomarker revealed by large-scale of public databases and clinical samples in uterine corpus endometrial carcinoma

Abstract Background: Uterine corpus endometrial carcinoma (UCEC) is the fourth most common cancer among women worldwide. Lysine-specific demethylase 4B (KDM4B) is overexpressed or dysregulated in various cancers and is associated...

PD-L1 Expression in Mismatch Repair-deficient Endometrial Carcinoma and Tumor-associated Immune Cells: Differences Between MLH1 Methylated and Nonmethylated Subgroups

Mismatch repair (MMR)-deficient endometrial carcinomas show increased programmed cell death-ligand 1 (PD-L1) expression compared with MMR-intact endometrial carcinomas, but there are limited data regarding PD-L1 expression between sporadic and inherited carcinomas exhibiting MMR loss. Most of the studies investigating PD-L1 expression in endometrial carcinoma have used tissue microarrays and did not examine all tumor blocks. In this study, we analyzed the expression of PD-L1 in resection specimens of 176 consecutive endometrial carcinomas using all tumor blocks; we compared PD-L1 expression in MMR-deficient endometrial carcinomas, including the MLH1 and PMS2-loss subgroup, and the other MMR-loss subgroups (MSH2 and MSH6, isolated PMS2, and isolated MSH6), with the MMR-intact subgroup. MLH1 methylation was performed in tumors with MLH1 and PMS2 loss. Tumor cell (TC) and tumor-associated immune cell (IC) PD-L1 positivity with a 1% cutoff was observed in 21% (n=37) and 66.5% (n=117) of cases, respectively, and with a 5% cutoff in 5.1% (n=9) and 39.8% (n=70) of cases, respectively. MMR protein deficiency was a statistically significant parameter associated with IC PD-L1 positivity, with 1% and 5% cutoffs on multivariate analysis [odds ratio (OR)=5.236, 95% confidence interval (CI)=2.075-13.211, P=0.001, and OR=3.702, 95% CI=1.759-7.791, P=0.001, respectively]. The multivariate analysis showed that IC PD-L1 positivity, using both 1% and 5% cutoffs, was significantly associated with the MLH1 and PMS2 loss compared with the MMR protein-intact subgroup (MLH1 and PMS2 loss for 1% cutoff: OR=5.104, 95% CI=1.876-13.881, P=0.001, and for 5% cutoff: OR=3.322, 95% CI=1.540-7.166, P=0.002). Squamous differentiation was an independent predictor for TC PD-L1 positivity, with a 5% cutoff (OR=6.102, 95% CI=1.280-10.096, P=0.026). Larger tumor size was an independent predictive factor for IC PD-L1 positivity with a 1% cutoff (OR=6.757, 95% CI=1.569-29.109, P=0.010). Overall, 48 (92.3%) of 52 MLH1 methylated tumors showed IC PD-L1 positivity with 1% cutoff, and 34 (65.4%) of 52 MLH1 methylated tumors showed IC PD-L1 positivity with 5% cutoff. Our results show a higher rate of IC PD-L1 positivity than in previous studies. This is likely due in part to the use of all tumor blocks. MLH1 and PMS2 loss was an independent predictive factor for IC PD-L1 positivity, with both 1% and 5% cutoffs. Using univariate analysis, we observed decreased disease-free survival for IC PD-L1 positivity ≥5%. Our study results should now be tested and proven in larger cohorts, with longer follow-up data.

CDKN2B-AS1 Promotes Malignancy as a Novel Prognosis-Related Molecular Marker in the Endometrial Cancer Immune Microenvironment

The prognosis of patients with endometrial cancer (EC) is closely associated with immune cell infiltration. Although abnormal long non-coding RNA (lncRNA) expression is also linked to poor prognosis in patients with EC, the function and action mechanism of immune infiltration-related lncRNAs underlying the occurrence and development of EC remains unclear. In this study, we analyzed lncRNA expression using The Cancer Genome Atlas and clinical data and identified six lncRNAs as prognostic markers for EC, all of which are associated with the infiltration of immune cell subtypes, as illustrated by ImmLnc database and ssGSEA analysis. Real-time quantitative polymerase chain reaction showed that CDKN2B-AS1 was significantly overexpressed in EC, whereas its knockdown inhibited the proliferation and invasion of EC cells and the in vivo growth of transplanted tumors in nude mice. Finally, we constructed a competing endogenous RNA regulatory network and conducted Gene Ontology enrichment analysis to elucidate the potential molecular mechanism underlying CDKN2B-AS1 function. Overall, we identified molecular targets associated with immune infiltration and prognosis and provide new insights into the development of molecular therapies and treatment strategies against EC.

Tertiary lymphoid structures are associated with favorable survival outcomes in patients with endometrial cancer

Immunotherapy has experienced remarkable growth recently. Tertiary lymphoid structures (TLSs) and B cells may play a key role in the immune response and have a survival benefit in some solid tumors, but there have been no reports about their role in endometrial cancer (EC). We investigated the clinicopathological and pathobiological characteristics of the tumor microenvironment (TME) in EC. Patients with EC at Kyoto University Hospital during 2006–2011 were retrospectively included. In 104 patients with EC who met study inclusion criteria, 81 (77.9%) had TLSs, which consisted of areas rich in CD20⁺ B cells, CD8⁺ T cells, CD4⁺ T cells, and CD38⁺ plasma cells. The absence of TLS was independently associated with tumor progression (HR, 0.154; 95% CI, 0.044–0.536; P = 0.003). Patients with TLSs that included CD23⁺ germinal centers had better PFS. All tumor infiltrating lymphocytes were counted in the intratumor site. The number of CD20⁺ B cells was significantly larger in patients with TLSs than in those without TLS (P < 0.001). CD20⁺ B cells numbers were positively correlated with other TLSs. The larger number of CD20⁺ B cell was associated with better PFS (P = 0.015). TLSs and B cell infiltration into tumors are associated with favorable survival outcomes in patients with EC. They may represent an active immune reaction of the TME in endometrial cancer.

Immune checkpoint inhibitor sensitivity of DNA repair deficient tumors

Faithful DNA replication is necessary to maintain genome stability and implicates a complex network with several pathways depending on DNA damage type: homologous repair, nonhomologous end joining, base excision repair, nucleotide excision repair and mismatch repair. Alteration in components of DNA repair machinery led to DNA damage accumulation and potentially carcinogenesis. Preclinical data suggest sensitivity to immune checkpoint inhibitors in tumors with DNA repair deficiency. Here, we review clinical studies that explored the use of immune checkpoint inhibitor in patient harboring tumor with DNA repair deficiency.

Development and validation of m6A regulators' prognostic significance for endometrial cancer

BACKGROUND

Endometrial cancer (EC) is the sixth most common cancer in women globally. It has been found that the expression levels of m6A regulators can be potentially used for prognostic stratification in some cancers, but the role of m6A regulators in EC prognosis remains unclear.

METHODS

The data of 584 EC samples were downloaded from The Cancer Genome Atlas and the mRNA expression profiles of 20 m6A regulators were analyzed, followed by functional enrichment analysis, immune infiltration analysis, and least absolute shrinkage and selection operator method-COX regression analysis.

RESULTS

The mRNA expression levels of 20 m6A regulators were significantly different between cancer samples across different grades. The 548 EC samples could be clearly divided into 2 clusters. Kaplan-Meier survival analysis proved that these two groups had highly different overall survival probabilities. Besides, the univariate regression analysis further reserved eight genes related to overall survival from the 20 m6A regulators. We established a prognostic signature including two genes, that is, IGF2BP1 and YTHDF3, that showed a strong ability for stratifying prognostically different EC patients. We identified 3239 differentially expressed genes between the high- and low-risk groups, involving in multiple biological processes and signaling pathways. Meanwhile, 6 differentially infiltrated immune cell types between the high- and low-risk groups could effectively distinguish the high- and low-risk EC groups. The expressions of immune checkpoints were different between high- and low-risk EC patients.

CONCLUSION

We first report the prognostic role of m6A regulators in EC, which should contribute to a better understanding of the underlying mechanisms of EC pathogenesis and progression.

Immunologic factors involved in the malignant transformation of endometriosis to endometriosis-associated ovarian carcinoma

INTRODUCTION

Endometriosis is a risk factor for low-grade serous, clear cell, and endometroid ovarian carcinoma. In both endometriosis and ovarian carcinoma, immunological factors are associated with clinical outcome. Chronic inflammation in endometriosis may be linked to tumorigenesis, but exact processes contributing to endometriosis-associated ovarian carcinoma remain unknown. This review aims to describe potential immunological factors involved in the malignant transformation of endometriosis into ovarian carcinoma.

METHODS

PubMed and Embase were searched from inception up to October 2020 for studies comparing immunological processes in endometriosis and endometriosis-associated ovarian carcinoma.

RESULTS

Detailed analysis of immune components in the malignant transformation of endometriosis into endometriosis-associated ovarian carcinoma is lacking. Altered levels of chemokines and cytokines as IL-6, IL-8, IL-10, and TNF-α are reported and the function, number and polarization of NK cells, dendritic cells, and monocytes differ between endometriosis and associated ovarian carcinoma compared to healthy tissue. In addition, altered inflammasome and complement systems, indicate a role for the immune system in the carcinogenesis of endometriosis.

CONCLUSION

Chronic inflammation in endometriosis may potentially drive inflammation-induced carcinogenesis in endometriosis-associated ovarian carcinoma. Exact immunological pathways and cellular processes remain unknown and require more thorough investigation.

Research progress of PARP inhibitor monotherapy and combination therapy for endometrial cancer

Endometrial cancer is one of the three most common malignant tumors in the female reproductive system. Advanced and recurrent endometrial cancers have poor prognoses and lack effective treatments. Poly(ADP-ribose) polymerase (PARP) inhibitors have been applied to many different types of tumors, and they can selectively kill tumor cells that are defective in homologous recombination repair. Endometrial cancer is characterized by mutations in homologous recombination repair genes; accordingly, PARP inhibitors have achieved positive results in off-label treatments of endometrial cancer cases. Clinical trials of PARP inhibitors as monotherapies and within combination therapies for endometrial cancer are ongoing. For this review, we searched PubMed with "endometrial cancer" and "PARP inhibitor" as keywords, and we used "olaparib", "rucaparib", "niraparib" and "talazoparib" as search terms in clinicaltrials.gov for ongoing trials. The literature search ended in October 2020, and only English-language publications were selected. Multiple studies confirm that PARP inhibitors play an important role in killing tumor cells with defects in homologous recombination repair. Its combination with immune checkpoint inhibitors, PI3K/AKT/mTOR pathway inhibitors, cell cycle checkpoint inhibitors, and other drugs can improve the treatment of endometrial cancer.

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.

Immunotherapy-Related Imaging Findings in Patients with Gynecological Malignancies: What Radiologists Need to Know

Immunotherapy is an effective treatment option for gynecological malignancies. Radiologists dealing with gynecological patients undergoing treatment with immune checkpoint inhibitors should be aware of unconventional immune-related imaging features for the evaluation of tumor response and immune-related adverse events. In this paper, immune checkpoint inhibitors used for gynecological malignancies and their mechanisms of action are briefly presented. In the second part, patterns of pseudoprogression are illustrated, and different forms of immune-related adverse events are discussed.

Myeloid-Derived Suppressor Cells as Therapeutic Targets in Uterine Cervical and Endometrial Cancers

Uterine cervical and endometrial cancers are the two most common gynecological malignancies. As demonstrated in other types of solid malignancies, an increased number of circulating or tumor-infiltrating myeloid-derived suppressor cells (MDSCs) have also been observed in uterine cervical and endometrial cancers, and increased MDSCs are associated with an advanced stage, a short survival, or a poor response to chemotherapy or radiotherapy. In murine models of uterine cervical and endometrial cancers, MDSCs have been shown to play important roles in the progression of cancer. In this review, we have introduced the definition of MDSCs and their functions, discussed the roles of MDSCs in uterine cervical and endometrial cancer progression, and reviewed treatment strategies targeting MDSCs, which may exhibit growth-inhibitory effects and enhance the efficacy of existing anticancer treatments.

Molecularly Classified Uterine FIGO Grade 3 Endometrioid Carcinomas Show Distinctive Clinical Outcomes But Overlapping Morphologic Features

FIGO grade 3 endometrioid endometrial carcinoma (EEC) is a heterogenous group of tumors with variable molecular and clinicopathologic characteristics but is treated clinically as a single entity. There is a need for additional objective markers to help guide management. The aim of this study was to evaluate a cohort of FIGO grade 3 EEC to validate the prognostic impact of molecular classification using POLE mutation (POLE-mut) analysis and immunohistochemistry for p53 and mismatch repair proteins. A secondary aim was to assess for any morphologic or immunophenotypic correlates among the molecular groups. Ninety-five cases of FIGO grade 3 EEC who underwent a hysterectomy at our institution were identified. Ten tumors (11%) harbored POLE-mut, 35 tumors (37%) showed mismatch repair deficiency, 18 tumors (19%) showed aberrant p53 staining (p53-ab), and 26 cases (27%) lacked all of these findings and were classified as no specific molecular profile. Six separate cases harbored >1 abnormality (multiple classifier), 5 of which had POLE-mut. The POLE-mut group and multiple classifier group showed excellent clinical outcomes, the p53-ab group showed the worst clinical outcomes and the 2 remaining groups showed intermediate prognosis. While the POLE-mut tumors showed a statistically significant enrichment for morphologic features including serous-like atypia and lymphocytic infiltrates, these findings were seen across all 4 molecular groups. There was no correlation between molecular grouping and tumor immunophenotypic findings, but overall 18% and 24% of tumors were completely negative for PAX-8 and estrogen receptor, respectively. Five CTNNB1 mutations were identified, 3 of which occurred in the context of a POLE-mut (including 1 multiple classifier case with MLH1/PMS2 loss). Thus our study corroborates the prognostic impact of molecular classification of high-grade endometrioid carcinoma of the uterus, achieved by readily available immunohistochemical stains in addition to POLE-mut analysis.

Mutations in the RAS/MAPK Pathway Drive Replication Repair-Deficient Hypermutated Tumors and Confer Sensitivity to MEK Inhibition

The RAS/MAPK pathway is an emerging targeted pathway across a spectrum of both adult and pediatric cancers. Typically, this is associated with a single, well-characterized point mutation in an oncogene. Hypermutant tumors that harbor many somatic mutations may obscure the interpretation of such targetable genomic events. We find that replication repair-deficient (RRD) cancers, which are universally hypermutant and affect children born with RRD cancer predisposition, are enriched for RAS/MAPK mutations (P = 10^-8). These mutations are not random, exist in subclones, and increase in allelic frequency over time. The RAS/MAPK pathway is activated both transcriptionally and at the protein level in patient-derived RRD tumors, and these tumors responded to MEK inhibition in vitro and in vivo. Treatment of patients with RAS/MAPK hypermutant gliomas reveals durable responses to MEK inhibition. Our observations suggest that hypermutant tumors may be addicted to oncogenic pathways, resulting in favorable response to targeted therapies. SIGNIFICANCE: Tumors harboring a single RAS/MAPK driver mutation are targeted individually for therapeutic purposes. We find that in RRD hypermutant cancers, mutations in the RAS/MAPK pathway are enriched, highly expressed, and result in sensitivity to MEK inhibitors. Targeting an oncogenic pathway may provide therapeutic options for these hypermutant polyclonal cancers.This article is highlighted in the In This Issue feature, p. 1307.

Immunohistochemical Biomarkers as a Surrogate of Molecular Analysis in Ovarian Carcinomas: A Review of the Literature

The term "ovarian carcinoma" encompasses at least five different malignant neoplasms: high-grade serous carcinoma, low-grade serous carcinoma, endometrioid carcinoma, mucinous carcinoma, and clear cell carcinoma. These five histotypes demonstrated distinctive histological, molecular, and clinical features. The rise of novel target therapies and of a tailored oncological approach has demanded an integrated multidisciplinary approach in the setting of ovarian carcinoma. The need to implement a molecular-based classification in the worldwide diagnostic and therapeutic setting of ovarian cancer demanded a search for easy-to-use and cost-effective molecular-surrogate biomarkers, relying particularly on immunohistochemical analysis. The present review focuses on the role of immunohistochemistry as a surrogate of molecular analysis in the everyday diagnostic approach to ovarian carcinomas.

Immunogenomic landscape of gynecologic carcinosarcoma

OBJECTIVE

Carcinosarcoma (CS) of the uterus or ovary is a rare, biphasic tumor comprising epithelial and mesenchymal elements, and exhibits more aggressive clinical features than its carcinoma counterpart. Four molecular subtypes of CS were recently established based on genomic aberration profiles (POLE, MSI, CNH, and CNL) and shown to be associated with multiple clinicopathological parameters, including patient outcomes. However, the role of the immune microenvironment in CS remains unclear. Here, we investigated the influence of the immune cells that infiltrate CS to better understand the immunological status of gynecological CS.

METHODS

Tumor immune microenvironmental analyses on CS samples were performed using immune cell profiling with RNA-seq, transcriptomic subtyping with microenvironmental genes, and T-cell receptor repertoire assay. Carcinoma and sarcoma elements from CS samples were also assessed separately.

RESULTS

Relying on estimations of tumor-infiltrating cell types from RNA-seq data, POLE and MSI (hypermutator) tumors showed an enrichment of M1 macrophages, plasma cells and CD8⁺ T cells, whereas CNH and CNL (non-hypermutator) tumors had high levels of M2 macrophages. Further subclassification by immune-related, non-cancer genes identified a fraction of tumors with distinct patient outcomes, particularly those with the CNH genomic aberration subtype. T-cell heterogeneity was independently correlated with prolonged progression-free survival. Differential analysis of carcinoma and sarcoma elements identified many shared mutations but there was little overlap in the T-cell receptor repertoire between the two elements.

CONCLUSIONS

Tumor immune microenvironmental analyses could offer potential clinical utility in the stratification of gynecological CS above classification by genomic aberration subtype alone.

Dostarlimab in the treatment of recurrent or primary advanced endometrial cancer

Immune checkpoint inhibitors have demonstrated significant clinical activity across various tumor subtypes; however, their utility in gynecologic malignancies has thus far proven modest. Since the identification of a molecular subclassification system for endometrial cancer (EC), research in immune checkpoint inhibitor therapies has been focusing on certain subgroups predictive for response, particularly microsatellite instability hypermutated/DNA mismatch repair-deficient subtype. Dostarlimab, a PD-1 inhibitor, has demonstrated preliminary evidence of clinical activity and acceptable safety profile in patients with across recurrent EC, particularly microsatellite instability-hypermutated/DNA mismatch repair-deficient EC. This review outlines existing data for the efficacy and safety of dostarlimab in recurrent or advanced-stage EC.

A Review of Immune Checkpoint Blockade Therapy in Endometrial Cancer

Approximately 30% of primary endometrial cancers are microsatellite instability high/hypermutated (MSI-H), and 13% to 30% of recurrent endometrial cancers are MSI-H or mismatch repair deficient (dMMR). Given the presence of immune dysregulation in endometrial cancer as described, immune checkpoint blockade (ICB) has been explored as a therapeutic mechanism, both as monotherapy and in combination with cytotoxic chemotherapy, other immunotherapy, or targeted agents. In MSI-H or dMMR advanced endometrial cancers, PD-1 inhibitors dostarlimab and pembrolizumab have shown response rates of 49% and 57%, respectively, whereas PD-L1 inhibitors avelumab and durvalumab have shown response rates of 27% and 43%, respectively. In microsatellite stable (MSS) or PD-L1-positive advanced endometrial cancers, modest activity of PD-1 inhibitors nivolumab and dostarlimab and PD-L1 inhibitors atezolizumab, avelumab, and durvalumab has been seen, with response rates ranging from 3% to 23%. Based on substantial activity in a phase Ib/II study, the U.S. Food and Drug Administration (FDA) granted lenvatinib and pembrolizumab combination therapy accelerated approval in 2019 for the treatment of advanced endometrial cancer that is not MSI-H or dMMR and has progressed following prior therapy. Although these developments have been highly impactful, a more robust understanding of the molecular and immunologic drivers of response and resistance will be critical to optimally design next-generation studies in endometrial cancer.

Role of Tumor Mutation Burden Analysis in Detecting Lynch Syndrome in Precision Medicine: Analysis of 2,501 Japanese Cancer Patients

BACKGROUND

Tumor mutation burden (TMB) is the total exonic mutation count per megabase of tumor DNA. Recent advances in precision medicine occasionally detect Lynch syndrome (LS) by germline sequencing for mismatch-repair (g.MMR) genes but not using TMB. The current study analyzes the utility of TMB in detecting LS.

METHODS

Whole-exome sequencing (ion-semiconductor sequencing) was performed for somatic and germline DNA from 2,501 various cancer patients to detect TMB and g.MMR sequencing. MMR IHC was conducted when high TMB (≥10) was detected in LS-related cancers with an additional condition of wild-type BRAF in colorectal cancers. Target sequencing and multiplex ligation-dependent probe amplification (MLPA) were further performed for g.MMR genes in MMR-deficient cancers (TMB-based g.MMR target sequencing). We compared universal sequencing and TMB-based target sequencing in their sensitivity for detecting LS.

RESULTS

LS was detected in 16 (0.6%) of the 2,501 patients: 1.1% (9/826) of colorectal cancer patients, 16.2% (6/37) of endometrial cancer patients, and 14.3% (1/7) of small intestine cancer patients. TMB-based g.MMR target sequencing (81.3%) showed superior sensitivity for detecting LS than universal g.MMR sequencing (56.3%; P = 0.127) but missed 3 LS patients (1 with a low-TMB cancer, 1 with a BRAF-mutant colorectal cancer, and 1 with an MMR-proficient cancer). Ion-semiconductor sequencing could detect single-nucleotide substitutions but not large deletions. POL-mutated cancers showed extremely high TMBs (48.4-749.2).

CONCLUSIONS

g.MMR target sequencing, combined with TMB, somatic BRAF mutation, and MMR IHC is an effective strategy for detecting LS.

IMPACT

TMB can be a biomarker for detecting LS in precision medicine.

PARP Inhibitors in Endometrial Cancer: Current Status and Perspectives

Advanced, recurrent and metastatic endometrial cancer (EC) has a dismal prognosis due to poor response rates to conventional treatments. In the era of precision medicine, the improved understanding of cancer genetics and molecular biology has led to the development of targeted therapies, such as poly (ADP-ribose) polymerase (PARP) inhibitors. This class of drugs that inhibit PARP enzymes has been investigated in many different types of tumors and its use in the treatment of gynecological malignancies has rapidly increased over the past few years. Data from several clinical trials showed that PARP inhibitors have a beneficial role in cancers with a defect in the homologous DNA recombination system, regardless of the BRCA mutational status. Since EC frequently shows mutations in PTEN and TP53 genes, indirectly involved in the homologous DNA recombination pathway, several in vivo and in vitro studies investigated the efficacy of PARP inhibitors in EC, showing promising results. This review will discuss the use of PARP inhibitors in endometrial cancer, summarizing data from preclinical studies and providing an overview of the ongoing trials, with a special focus on the development of combined treatment strategies with PARP inhibitors and immune checkpoint inhibitors.

The Latest Findings of PD-1/PD-L1 Inhibitor Application in Gynecologic Cancers

Gynecologic cancers account for approximately 11% of the newly diagnosed cancers in women in the United States and for 18% globally. The presence of tumor-infiltrating lymphocytes (TILs) influences the clinical outcome of cancer patients and immune checkpoint inhibitors (ICIs), including anti programmed cell death protein-1 (anti-PD-1), anti-programmed death-ligand 1 (anti-PD-L1), and anticytotoxic T-lymphocyte antigen 4 (anti-CTLA-4), which have been approved for treating different types of malignancies. Antibodies targeting the PD-1/PD-L1 checkpoint have shown dynamic and durable tumor regressions, suggesting a rebalancing of the host-tumor interaction. There are several the US food and drug administration (FDA)-approved ICIs targeting PD-1, including pembrolizumab and nivolumab, as well as those targeting PD-L1, including avelumab, atezolizumab, and durvalumab for melanoma, renal cell cancer, colorectal cancer, head and neck cancer, cervix cancer, urothelial cancer, and lung cancer. Current pre-clinical and clinical studies assessing PD-1/PD-L1 inhibitors in several gynecologic cancers have reported significant antitumor activity. In this review, we investigate pre-clinical and clinical studies that describe the safety and efficacy of anti-PD-1/PD-L1 antibodies, with a particular focus on ongoing clinical trials, analyzing the oncological outcome and adverse effects of ICIs in gynecologic cancers.

Correlation of PD-L1 expression with immunohistochemically determined molecular profile in endometrial carcinomas

Endometrial carcinoma programmed death-ligand 1 (PD-L1) expression in tumor cells (TCs) and tumor-associated inflammatory cells (ICs) have recently been reported in several studies which vary in terms of their cohort size, design, and methodology. We aimed to assess PD-L1 staining in endometrial carcinomas and correlate this with clinical and pathological factors and PTEN, ARID1A, p53, and MMR protein expression. PD-L1 immunohistochemistry was performed on whole tissue sections of all tumor blocks of 59 consecutive unselected endometrial carcinomas between November 2018 and September 2019. TC and IC PD-L1 positivity with a 1% cut-off value was observed in 10.2% and 67.8% of cases, respectively, and with a 5% cut-off value in 3.4% and 42.4% of cases, respectively. TC PD-L1 positivity with both 1% and 5% cut-off values was significantly related to ARID1A loss (p = 0.001 and p = 0.046, respectively). IC PD-L1 positivity with 1% and 5% cut-off values and combined score were significantly associated with MMR protein deficiency (p = 0.041, p = 0.031, and p = 0.028, respectively). Advanced stage tumors exhibited more frequent PD-L1 expression in ICs (p = 0.039). MELF-type myometrial invasion pattern was more common in tumors with ARID1A loss (p = 0.047). We observed higher rates of IC PD-L1 positivity in endometrial carcinomas than documented in prior studies; this may be related to our usage of "recent" paraffin blocks and whole tissue sections of all tumor blocks. There was a much higher PD-L1 expression in the ICs compared to TCs in our cases. We confirm a previously documented association between MMR deficiency and PD-L1 expression and show a novel association between ARID1A loss and PD-L1 expression in endometrial carcinomas. ARID1A loss represents a potential biomarker of immune checkpoint inhibitor response in endometrial carcinoma.

ATM mutations as an independent prognostic factor and potential biomarker for immune checkpoint therapy in endometrial cancer

The morbidity and mortality of endometrial cancer has been increasing over years. Ataxia telangiectasia mutated (ATM) gene, encoding a protein kinase participated in the response to DNA damage, is frequently mutated in endometrial cancer patients. However, the potential relationship between ATM mutations and the progression of endometrial cancer remains unclear. We performed an integrative bioinformatics analysis to investigate the relationship between ATM mutational status with clinical outcomes and tumor microenvironment in endometrial cancer patients. The whole exome sequencing data, RNA sequencing data and clinical information were collected from The Cancer Genome Atlas (TCGA) dataset. We found that mutation in the ATM gene was an independent prognostic factor for endometrial cancer. Antitumor immune pathways were enriched in endometrial tumors with ATM mutations. The tumor-infiltrating T lymphocytes, especially cytotoxic lymphocytes, were generally more abundant in tumors with ATM mutations. Furthermore, patients with ATM mutations exhibited higher tumor mutational burden, higher neoantigen load and increased expression levels of some immune checkpoints. In conclusion, the present study indicated that ATM mutations were linked to longer overall survival of endometrial cancer. Our findings may add better understanding for potential immunotherapy of endometrial cancer.

An immune competent orthotopic model of endometrial cancer with metastasis

Endometrial cancer is the most common gynecologic malignancy in the U.S. with metastatic disease remaining the major cause of patient death. Therapeutic strategies have remained essentially unchanged for decades. A significant barrier to progression in treatment modalities stems from a lack of clinically applicable in vivo models to accurately mimic endometrial cancer; specifically, ones that form distant metastases and maintain an intact immune system. To address this problem, we have established the first immune competent murine orthotopic tumor model for metastatic endometrial cancer by creating a green fluorescent protein labeled cell line from an endometrial cancer that developed in a Pgr ^cre/+ Pten ^f/f Kras ^G12D genetically engineered mouse. These cancer cells were grafted into the abraded uterine lumen of ovariectomized recipient mice treated with estrogen and subsequently developed local and metastatic endometrial tumors. We noted primary tumor formation in 59% mixed background and 86% of C57BL/6 animals at 4 weeks and distant lung metastases in 78% of mice after 2 months. This immunocompetent orthotopic tumor model closely resembles some human metastatic endometrial cancer, modeling both local metastasis and hematogenous spread to lung and has significant potential to advance the study of endometrial cancer and its metastasis.

Expression of Immunomodulatory Molecules PD-1, PD-L1, and PD-L2, and their Relationship With Clinicopathologic Characteristics in Endometrial Cancer

Chemotherapeutic agents are not very effective in treating advanced endometrial cancers (ECs). Recent studies have demonstrated the immune evasion mechanism of tumors and possible remedies. Programmed cell death protein 1 (PD-1), programmed death ligand 1 (PD-L1), and programmed death ligand 2 (PD-L2) are immunomodulator molecules that have been the focus of research in lung cancer, melanoma, and renal cell cancer. However, there are few studies concerning EC. This retrospective study aimed to determine PD-1, PD-L1, and PD-L2 expression immunohistochemically in EC, and to study their correlation with clinicopathologic tumor characteristics. This study comprised 127 patients with EC. Anti PD-1, PD-L1, and PD-L2 antibodies were examined immunohistochemically on sections obtained from tissue microarray paraffin blocks. No staining with PD-1 in tumor cells was seen; however, we found positive staining in tumor cells at 36.2% with PD-L1 and 64.4% with PD-L2, and at 61.6% with PD-1, 36.2% with PD-L1, and 93.2% with PD-L2 in immune cells. When comparing staining and clinicopathologic findings, most of the PD-L1 negative tumors (both in tumor and immune cells) were FIGO Stage I, which was significantly higher than stage II-III-IV tumors (P<0.05). There was a statistically significant association between the FIGO grade and the PD-L1 score in immune cells (P=0.009), and between staining of PD-1, PD-L1, and PD-L2 and age (P=0.004, 0.013, and 0.043, respectively). Interaction between PD-1, PD-L1, and PD-L2 may be a potential target for immunotherapy in elderly and advanced stage EC patients.

Tumor Mutational Burden as a Predictive Biomarker for Response to Immune Checkpoint Inhibitors: A Review of Current Evidence

Treatment with immune checkpoint inhibitors (ICPIs) extends survival in a proportion of patients across multiple cancers. Tumor mutational burden (TMB)-the number of somatic mutations per DNA megabase (Mb)-has emerged as a proxy for neoantigen burden that is an independent biomarker associated with ICPI outcomes. Based on findings from recent studies, TMB can be reliably estimated using validated algorithms from next-generation sequencing assays that interrogate a sufficiently large subset of the exome as an alternative to whole-exome sequencing. Biological processes contributing to elevated TMB can result from exposure to cigarette smoke and ultraviolet radiation, from deleterious mutations in mismatch repair leading to microsatellite instability, or from mutations in the DNA repair machinery. A variety of clinical studies have shown that patients with higher TMB experience longer survival and greater response rates following treatment with ICPIs compared with those who have lower TMB levels; this includes a prospective randomized clinical trial that found a TMB threshold of ≥10 mutations per Mb to be predictive of longer progression-free survival in patients with non-small cell lung cancer. Multiple trials are underway to validate the predictive values of TMB across cancer types and in patients treated with other immunotherapies. Here we review the rationale, algorithm development methodology, and existing clinical data supporting the use of TMB as a predictive biomarker for treatment with ICPIs. We discuss emerging roles for TMB and its potential future value for stratifying patients according to their likelihood of ICPI treatment response. IMPLICATIONS FOR PRACTICE: Tumor mutational burden (TMB) is a newly established independent predictor of immune checkpoint inhibitor (ICPI) treatment outcome across multiple tumor types. Certain next-generation sequencing-based techniques allow TMB to be reliably estimated from a subset of the exome without the use of whole-exome sequencing, thus facilitating the adoption of TMB assessment in community oncology settings. Analyses of multiple clinical trials across several cancer types have demonstrated that TMB stratifies patients who are receiving ICPIs by response rate and survival. TMB, alongside other genomic biomarkers, may provide complementary information in selecting patients for ICPI-based therapies.

Updates on adjuvant chemotherapy and radiation therapy for endometrial cancer

PURPOSE OF REVIEW

This article will provide an opinion on adjuvant treatment of stage I-III endometrial cancer based on existing and evolving evidence.

RECENT FINDINGS

For early-stage (I and II) intermediate risk endometrial cancer, vaginal brachytherapy reduces the risk of locoregional relapse. Recent studies have investigated the use of chemotherapy in early stage, high-risk patient population, but did not demonstrate a survival benefit. As such, chemotherapy is only recommended for selected patients at high risk for distant recurrence. On the other hand, for stage III disease, chemotherapy has a well established role. A landmark trial recently reported confirmed that chemoradiation improves recurrence-free survival compared with radiation alone in stage III endometrial cancer. However, in another randomized phase III trial, chemoradiotherapy was not superior to chemotherapy alone in this group, raising questions as to whether addition of radiation is necessary. Therefore, improved risk stratification using molecular markers in addition to traditional pathological criteria is critically needed to better predict the risk of local and systemic recurrence and to assist therapy decision-making.

SUMMARY

Endometrial cancer care is evolving and recent pivotal trials highlight the significance of chemotherapy to the treatment of stage III endometrial cancer and not to the approach for stage I and II cancer. The role of radiation therapy for stage III disease is raised into question.

Clinical outcomes of patients with POLE mutated endometrioid endometrial cancer

OBJECTIVES

Assess outcomes of a clinical cohort of patients with endometrioid endometrial cancer (EEC) harboring somatic POLE exonuclease domain mutations (EDMs).

METHODS

Patients were consented to a protocol of tumor-normal massively parallel sequencing of 410-468 cancer related genes. EECs subjected to sequencing from 2014 to 2018 were reviewed. Tumors with somatic POLE EDMs were identified. EECs were assessed for microsatellite instability (MSI) using MSIsensor and immunohistochemical analysis for mismatch repair (MMR) proteins.

RESULTS

Of the 451 EECs sequenced, 23 had a POLE EDM (5%): 20 primary and 3 recurrent tumors sequenced. Nineteen cases (83%) were stage I/II and 4 (17%) were stages III/IV. Thirteen EECs (57%) were of FIGO grades 1/2, 10 (43%) grade 3. All patients were treated with surgery and 17 (89%) received adjuvant therapy. Five (22%) demonstrated loss of DNA MMR protein expression, none were due to Lynch syndrome. MSIsensor scores were conclusive for 21 samples: 19 were microsatellite stable and 2 MSI-high. After median follow-up of 30 months, 4/23 (17%) developed recurrences: 3 with initial grade 3 stage I and 1 with grade 1 stage III disease. One patient with grade 2 stage IV EEC had progressive disease after treatment.

CONCLUSIONS

Patients with POLE EDM EEC have been shown to have a favorable prognosis. In this real-world cohort of patients, de novo metastatic disease and recurrences in initially uterine-confined cases were observed. Further research is warranted before incorporating the presence of POLE EDM into decision-making regarding adjuvant therapy.

Endometrial Cancer Stem Cells: Role, Characterization and Therapeutic Implications

Endometrial cancer (EC) is the most frequent gynecological cancer. In patients with relapsed and advanced disease, prognosis is still dismal and development of resistance is common. In this context, endometrial Cancer Stem Cells (eCSC), stem-like cells capable to self-renewal and differentiation in mature cancer cells, represent a potential field of expansion for drug development. The aim of this review is to characterize the role of eCSC in EC, their features and how they could be targeted. CSC are involved in progression, invasiveness and metastasis (though epithelial to mesenchimal transition, EMT), as well as chemoresistance in EC. Nevertheless, isolation of eCSC is still controversial. Indeed, CD133, Aldheyde dehydrogenase (ALDH), CD117, CD55 and CD44 are enriched in CSCs but there is no universal marker nowadays. The most frequently activated pathways in eCSC are Wingless-INT (Wnt)/β-catenin, Notch1, and Hedghog, with a high expression of self-renewal transcription factors like Octamer binding transcription factor 4 (OCT), B Lymphoma Mo-MLV Insertion Region 1 Homolog (BMI1), North American Network Operations Group Homebox protein (NANOG), and SRY-Box 2 (SOX2). These pathways have been targeted with selective drugs alone or in combination with chemotherapy and immunotherapy. Unfortunately, although preclinical results are encouraging, few clinical data are available.

Immunohistochemical mismatch repair proteins expression as a tool to predict the melanoma immunotherapy response

In difference to other solid malignancies, the identification of biomarkers for the prediction of malignant melanoma (MM) response to immunotherapy is limited. The aim of the current study was to evaluate the immunohistochemical (IHC) expression of MMR proteins in a cohort of MM metastatic patients receiving anti PD-1 treatments. The therapeutic response of patients was also retrospectively assessed. The cohort of the current study included 14 patients with advanced MM that had received anti PD-1 from January 2014 to December 2016 (12 males, 2 females; average age, 71 years; age range, 47–88 years). IHC analysis of MLH1, PMS2, MSH2 and MSH6 proteins was performed on paraffin-embedded primary tumor samples from each patient and on the 23 available metastasis specimens obtained from the Division of Pathology (University of Modena and Reggio Emilia). The results revealed that 7% of the primary melanoma tissue obtained from the patient cohort exhibited the loss of expression of at least one MMR protein. Three samples from one patient, including one primary melanoma and two metastases, exhibited no MSH6 expression and had the most successful response to anti PD-1 treatment, with a progression-free survival and overall survival of 956 and 2,546 days, respectively. In conclusion, the assessment of MMR protein expression represents a potential predictive marker that may have critical importance for patients with primary and metastatic MM, primarily as criterion for the adoption of immunotherapy treatments.

β-arrestin-2 up-regulates toll-like receptor 2 signaling and inhibits apoptosis in human endometrial cancer heterotransplants in nude mice

BACKGROUND

β-arrestin-2(Arr2) functions as an anti-apoptotic factor and affects cell proliferation, but its downstream molecular pathway in endometrial carcinoma (EC) is still unclear. This study aimed to investigate the effects of the stable overexpression of Arr2 on the proliferation and apoptosis of human EC heterotransplants and the expression of associated molecules, including Toll-like receptor 2(TLR2), serine-threonine kinase Akt (Akt), glycogen synthase kinase-3β(GSK3β) and some typical inflammatory cytokines such as NF-κB p56, TNF-α and IL-6 & IL-8.

METHODS

Human EC cell line Ishikawa, stably transfected with Arr2 full-length plasmid, was injected subcutaneously into nude mice. They were treated with 0, 10, 20 mg/kg paclitaxel and the volume and weight of the tumor tissue were measured and calculated. The necrotic index were assessed by H&E staining and microscopic observation. The levels of caspase-3, caspase-9, TLR2, NF-κB p56, Akt, GSK3β were measured by western blot, and the levels of TNF-α, IL-6, IL-8 were measured by real-time PCR.

RESULTS

We found that Arr2 overexpression promoted the growth of human EC heterotransplants. Arr2 attenuated the promotion of caspase-3 and caspase-9 by paclitaxel and mediated the increase of TLR2 and several inflammatory cytokines. The levels of Akt and GSK3β were not affected.

CONCLUSION

Arr2 overexpression was associated with the increase of TLR2 and several inflammatory factors, meanwhile inhibited paclitaxel-induced anti-tumor effect on human EC heterotransplants.

Dramatic response of metastatic cutaneous angiosarcoma to an immune checkpoint inhibitor in a patient with xeroderma pigmentosum: whole-genome sequencing aids treatment decision in end-stage disease

"Mutational signatures" are patterns of mutations that report DNA damage and subsequent repair processes that have occurred. Whole-genome sequencing (WGS) can provide additional information to standard diagnostic techniques and can identify therapeutic targets. A 32-yr-old male with xeroderma pigmentosum developed metastatic angiosarcoma that was unresponsive to three lines of conventional sarcoma therapies. WGS was performed on his primary cancer revealing a hypermutated tumor, including clonal ultraviolet radiation-induced mutational patterns (Signature 7) and subclonal signatures of mutated DNA polymerase epsilon (POLE) (Signature 10). These signatures are associated with response to immune checkpoint blockade. Immunohistochemistry confirmed high PD-L1 expression in metastatic deposits. The anti-PD-1 monoclonal antibody pembrolizumab was commenced off-label given the POLE mutation and high mutational load. After four cycles, there was a significant reduction in his disease with almost complete resolution of the metastatic deposits. This case highlights the importance of WGS in the analysis, interpretation, and treatment of cancers. We anticipate that as WGS becomes integral to the cancer diagnostic pathway, treatments will be stratified to the individual based on their unique genomic and/or transcriptomic profile, enhancing classical approaches of histologically driven treatment decisions.

Metformin suppresses cancer cell growth in endometrial carcinoma by inhibiting PD-L1

Endometrial cancer is the most common cancer of the female reproductive system in the developed countries. Metformin is a widely used medication that has been prescribed to treat type 2 diabetes. In recent years, metformin has been found to improve the survival prognosis of cancer patients clinically. We aimed to investigate inhibition of metformin on the proliferation of endometrial carcinoma. Metformin was used to treat endometrial cancer cell lines Ishikawa and RL95-2. The expression of programmed death-ligand 1 (PD-L1) in the treated cells was assessed by western blot. The tumor cell proliferation was evaluated by colony formation assay. The binding between PD-L1 and AMP-activated protein kinase (AMPK) was identified by co-immunoprecipitation. Ishikawa and RL95-2 cells were co-cultured with activated T cells to detect the survival of Ishikawa and RL95-2 cells in the presence or absence of metformin. Our results showed that metformin treatment on endometrial cancer cells Ishikawa and RL95-2 decreased the expression level of PD-L1 protein. Metformin treatment significantly activated T cells against Ishikawa and RL95-2 cells. We demonstrated that the inhibition of PD-L1 by metformin is dependent on the AMPK signaling protein, and that metformin promotes direct binding of the AMPK protein to the PD-L1 protein. We confirmed that metformin, a conventional medication used in diabetes therapy, holds anti-tumor activity in endometrial cancer. The suppression of metformin is relevant to the inhibition of PD-L1 expression and the activation of AMPK signaling protein, providing a novel mechanism in the anti-tumor property of metformin.

Mutational signatures and mutable motifs in cancer genomes

Cancer is a genetic disorder, meaning that a plethora of different mutations, whether somatic or germ line, underlie the etiology of the 'Emperor of Maladies'. Point mutations, chromosomal rearrangements and copy number changes, whether they have occurred spontaneously in predisposed individuals or have been induced by intrinsic or extrinsic (environmental) mutagens, lead to the activation of oncogenes and inactivation of tumor suppressor genes, thereby promoting malignancy. This scenario has now been recognized and experimentally confirmed in a wide range of different contexts. Over the past decade, a surge in available sequencing technologies has allowed the sequencing of whole genomes from liquid malignancies and solid tumors belonging to different types and stages of cancer, giving birth to the new field of cancer genomics. One of the most striking discoveries has been that cancer genomes are highly enriched with mutations of specific kinds. It has been suggested that these mutations can be classified into 'families' based on their mutational signatures. A mutational signature may be regarded as a type of base substitution (e.g. C:G to T:A) within a particular context of neighboring nucleotide sequence (the bases upstream and/or downstream of the mutation). These mutational signatures, supplemented by mutable motifs (a wider mutational context), promise to help us to understand the nature of the mutational processes that operate during tumor evolution because they represent the footprints of interactions between DNA, mutagens and the enzymes of the repair/replication/modification pathways.