Prognostic role of EZH2 in gliomas: a meta-analysis

Death-ision: the link between cellular resilience and cancer resistance to treatments

One of the key challenges in defeating advanced tumors is the ability of cancer cells to evade the selective pressure imposed by chemotherapy, targeted therapies, immunotherapy and cellular therapies. Both genetic and epigenetic alterations contribute to the development of resistance, allowing cancer cells to survive initially effective treatments. In this narration, we explore how genetic and epigenetic regulatory mechanisms influence the state of tumor cells and their responsiveness to different therapeutic strategies. We further propose that an altered balance between cell growth and cell death is a fundamental driver of drug resistance. Cell death programs exist in various forms, shaped by cell type, triggering factors, and microenvironmental conditions. These processes are governed by temporal and spatial constraints and appear to be more heterogeneous than previously understood. To capture the intricate interplay between death-inducing signals and survival mechanisms, we introduce the concept of Death-ision. This framework highlights the dynamic nature of cell death regulation, determining whether specific cancer cell clones evade or succumb to therapy. Building on this understanding offers promising strategies to counteract resistant clones and enhance therapeutic efficacy. For instance, combining DNMT inhibitors with immune checkpoint blockade may counteract YAP1-driven resistance or the use of transcriptional CDK inhibitors could prevent or overcome chemotherapy resistance. Death-ision aims to provide a deeper understanding of the diversity and evolution of cell death programs, not only at diagnosis but also throughout disease progression and treatment adaptation.

Immunoexpressions of PD-L1 and EZH2 in Endometrial Carcinoma: Associations with Clinicopathological Parameters

Background: This study investigated PD-L1 and EZH2 immunoexpressions in endometrial carcinomas (ECs) and correlated their associations with clinicopathological parameters and five-year survival outcomes. Methods: A cross-sectional, retrospective study was conducted on all ECs diagnosed between January 2014 and December 2018. Immunohistochemical staining for PD-L1 (clone 22C3) and EZH2 was performed on tumour samples, and their expression levels were assessed. Results: Among the 104 EC cases included, 19.2% (n = 20) overexpressed PD-L1, while 8.7% (n = 9) overexpressed EZH2. Most (n = 19/20, 95.0%) PD-L1-expressing tumour cells showed EZH2 immunonegativity. Likewise, most (n = 8/9, 88.9%) EZH2-expressing ECs were PD-L1-negative. Increased PD-L1 and EZH2 expressions in ECs were seen more frequently in women more than 60 years of age (p = 0.013 and p = 0.039). EZH2 overexpression was associated with higher tumour grade (p = 0.009) and more aggressive histological subtypes (p = 0.013), while PD-L1 expression was not significantly associated with tumour grade, tumour stage, histological subtypes, and lymph node status (p > 0.05). Kaplan-Meier survival analysis revealed that PD-L1-positive ECs had a significantly better five-year overall survival (OS) rate compared to PD-L1-negative ECs (p = 0.034). Conversely, EZH2 overexpression did not correlate with survival outcomes (p > 0.05). Notably, the combination of PD-L1 and EZH2 expression patterns on ECs (PD-L1-/EZH2+) portends the worst OS compared to other combined PD-L1/EZH2 expression patterns (p = 0.05). Conclusions: PD-L1 immunoexpression was associated with better survival outcomes in ECs, while overexpression of EZH2 was associated with higher tumour grade and aggressive histological subtypes, suggesting their potential utility as prognostic biomarkers in ECs.

Single-cell RNA sequencing reveals intra-tumoral heterogeneity of glioblastoma and a pro-tumor subset of tumor-associated macrophages characterized by EZH2 overexpression

BACKGROUND

Glioblastoma (GBM) is a highly heterogeneous disease with poor clinical outcome.

AIM

To comprehensively dissect molecular landscape of GBM and heterogeneous distribution and potential role of Enhancer of zeste homolog 2 (EZH2) in tumor microenvironment (TME).

METHODS

Single-cell RNA sequencing (scRNA-seq) analysis was performed in GBM samples from 8 patients. Deconvolution analysis, immunofluorescence (IF) microscopy, reverse-transcription quantitative polymerase chain reaction (RT-qPCR), colony formation experiments, and Cell Counting Kit-8 (CCK-8) assays were performed to confirmed the potential role of EZH2 in TME cells.

RESULTS

Malignant cells exhibited remarkable heterogeneity in abnormal metabolic patterns. A mesenchymal-2-like (MES2-like) GBM subcluster with glial-immune dual feature was firstly discovered, which were associated with highly activated hallmark pathways, immune evasion associated transcription factor (IRF8), and poor survival. The oncogene, EZH2, was heterogeneously expressed in malignant cells and immune cells consistent with proliferative genes, cell-cycle transcription factors, and similar activated hallmark pathways. In a tumor-associated macrophages (TAMs) subset (macrophage.3), EZH2 was highly expressed with similar changes of transcriptomic dynamics with cell-cycle genes and macrophages M2-phetotype genes. In addition, the subset tightly interacted with malignant cells. Deconvolution analysis showed increased abundance of the subset in GBM compared to low-grade glioma (LGG) and significant association with worse prognosis. Functional verification experiments confirmed the pro-tumor role of TAMs with EZH2 overexpression in GBM.

CONCLUSIONS

Our study illustrated a MES2-like GBM subcluster characterized by glial-immune dual feature and highlighted the pro-tumor role of a TAMs subset characterized by EZH2 overexpression.

Latest updates on cellular and molecular biomarkers of gliomas

Gliomas are the most common central nervous system malignancies, compromising almost 80% of all brain tumors and is associated with significant mortality. The classification of gliomas has shifted from basic histological perspective to one that is based on molecular biomarkers. Treatment of this type of tumors consists currently of surgery, chemotherapy and radiation therapy. During the past years, there was a limited development of effective glioma diagnostics and therapeutics due to multiple factors including the presence of blood-brain barrier and the heterogeneity of this type of tumors. Currently, it is necessary to highlight the advantage of molecular diagnosis of gliomas to develop patient targeted therapies based on multiple oncogenic pathway. In this review, we will evaluate the development of cellular and molecular biomarkers for the diagnosis of gliomas and the impact of these diagnostic tools for better tailored and targeted therapies.

High EZH2 Protein Expression Is a Poor Prognostic Predictor in IDH1 R132H-Negative Gliomas

Accumulating data indicates that enhancer of zeste homology 2 (EZH2) and isocitrate dehydrogenase 1 (IDH1) are implicated in promoting tumourigenesis in a myriad of malignancies including gliomas. We aimed to determine the immunoexpression of EZH2 in gliomas and its correlation with clinicopathological variables. The prognostic value of the combined immunoexpression of EZH2 and IDH1 was further explored in a retrospective analysis involving 56 patients with histologically confirmed gliomas in Universiti Kebangsaan Malaysia Medical Centre from 2010 to 2016. The patients were then followed up for a period of five years. EZH2 and IDH1 R132H immunoexpressions were performed and analysed on respective tissue blocks. Five-year progression-free survival (PFS) and overall survival (OS) were estimated by Kaplan−Meier analysis. Univariate and multivariate Cox proportional hazard regression models were performed to evaluate the value of EZH2 as an independent factor for the prediction of PFS and OS. High EZH2 immunoexpression was demonstrated in 27 (48.2%) gliomas. High EZH2 expression was significantly correlated with older age (p = 0.003), higher tumour grade (p < 0.001), negative IDH1 R132H immunoexpression (p = 0.039), a poor 5-year PFS (mean = 9.7 months, p < 0.001) and 5-year OS (mean = 28.2 months, p = 0.007). In IDH1 R132H-negative gliomas, there was a trend toward shorter 5-year PFS (mean = 8.0 months, p = 0.001) and 5-year OS (mean = 28.7 months, p = 0.06) in gliomas demonstrating high EZH2 expression compared with those with low EZH2 expression. High EZH2 immunoexpression is an unfavourable independent prognostic predictor of poor survival in gliomas. EZH2 analysis might therefore be of clinical value for risk stratification, especially in patients with IDH1 R132H-negative gliomas.

Effect of enhancer of zeste homolog 2 mutations on the prognosis of patients with myelodysplastic syndrome: A meta-analysis

BACKGROUND

Gene mutations with important prognostic roles have been identified in patients with myelodysplastic syndrome (MDS). Overall, it is not yet fully clear whether enhancer of zeste homolog 2 (EZH2) is affected and contributes to the disease in MDS patients. Thus, we performed a meta-analysis to investigate the effects of EZH2 mutations on the prognosis of patients with MDS.

METHODS

We searched English-language databases (PubMed, Embase, and Cochrane Library) for studies published on the effects of EZH2 mutations in MDS patients. The study had to include at least 1 of the following indices as therapeutic evaluation data: overall survival (OS), transformation time to leukemia, and International Prognostic Scoring System risk. Revman, version 5.2 software was used for all statistical processing. We calculated the risk ratio and the 95% confidence interval (CI) of continuous variables, and determined the hazard ratio and 95% CI of time-to-event data.

RESULTS

We included 5 studies with a total enrolment of 994 patients. There was a significant adverse effect on OS in the EZH2-mutation group compared to the unmutated group (hazard ratio = 2.47, 95% CI: 1.37-4.47, P < .00001), while the heterogeneity was relatively high (I = 68%). There was no significant correlation between EZH2 mutations and IPSS risk (low/int-1 vs int-2/high) (odds ratio: 0.69, 95% CI: 0.14-3.39, P = .65), with significant heterogeneity (I = 78%). The analysis did not show significant publication bias in the studies.

CONCLUSION

This meta-analysis indicated an adverse effect of EZH2 mutations with regard to OS in patients with MDS. However, larger cohort trials are still needed to better understand the prognostic impacts of EZH2 mutations on MDS patients.

Clinicopathological, Immunohistochemical and Molecular Genetic Study on Epithelioid Glioblastoma: A Series of Fifteen Cases with Literature Review

PURPOSE

To observe the clinicopathological, immunohistochemical, and molecular genetic features of epithelioid glioblastoma (E-GBM), and identify tumor-associated prognostic factors.

PATIENTS AND METHODS

The clinical and radiological data of fifteen cases of E-GBM were collected, and their pathological, immunohistochemical, and molecular features were examined. A 1p/19q analysis via FISH, MGMT promoter methylation by MS-PCR, and IDH1 and BRAF V600E mutation analysis by HRM-PCR were performed. The level of EZH2 expression was valuated by immunohistochemistry in 15 E-GBM cases, and the prognostic factors were analyzed in E-GBM patients. Fifteen non-E-GBM cases were used as a control.

RESULTS

The fifteen cases of E-GBM included twelve males and three females, with fourteen cases supratentorially located. Headache was the main symptom. Microscopy revealed that the tumors were composed of epithelioid cells and some rhabdoid cells. The epithelioid and rhabdoid cells displayed focal discohesion, scant intervening neuropil, a distinct cell membrane, eosinophilic cytoplasm, and a laterally positioned nucleus. Most tumors showed high mitosis, zonal necrosis, and microvascular hyperplasia. Immunohistochemical findings included epithelioid cells positive for GFAP, vimentin, nestin, S-100, and INI-1. The molecular findings included no deletions of 1p/19q, EGFR amplifications, or IDH1 mutations in any case, a methylated MGMT promoter in 46.7% (7/15) cases, and a BRAFV600E mutation in 46.7% (7/15) cases. EZH2 overexpression occurred in 60.0% (9/15) of E-GBM cases. E-GBM patients with OS (≤12 months) exhibited extensive necrosis (6/6), EZH2 overexpression (6/6), MGMT promoter unmethylation (5/6), BRAFV600E mutation (3/6), and treatment (surgery4/6). E-GBM patients with OS (>12 months) exhibited focal or limited necrosis, low or negative EZH2 expression, MGMT promoter methylation (2/3), BRAFV600E mutation (3/3), and treatment (surgery+radiotherapy/chemo-radiotherapy, 2/3).

CONCLUSION

E-GBM was a rare variant of glioblastoma, with histological epithelioid features and poor prognosis. Extensive necrosis, MGMT promoter unmethylation, EZH2 overexpression, and lack of adjuvant chemo-radiotherapy may indicate a poor prognosis.

Evaluation of EZH2 expression, BRAF V600E mutation, and CDKN2A/B deletions in epithelioid glioblastoma and anaplastic pleomorphic xanthoastrocytoma

INTRODUCTION

Epithelioid glioblastoma (EGBM) and anaplastic pleomorphic xanthoastrocytoma (APXA) are two rare entities with different prognoses. However, they share certain morphological and molecular features. MATERIALS AND METHODS: To better recognize EGBM and APXA and identify the prognostic factors associated with these tumors, EZH2 status, BRAF V600E mutations, and CDKN2A/B deletions were assessed in 15 APXA and 13 EGBM cases.

RESULTS

The expression level of EZH2 was found to increase with tumor grade. Overexpression of EZH2 occurred in 69.2% (9/13) of EGBM cases and 20% (3/15) of APXA cases. In addition, 72.7% (8/11) of EGBM and 12.5% (1/8) of APXA cases harbored a CDKN2A homozygous deletion based on fluorescence in situ hybridization. BRAF V600E mutations were detected in 80% (8/10) of EGBM cases and 42.9% (3/7) of APXA cases. Furthermore, EGBM, which exhibited co-existing low-grade glioma-like lesions, was found to have strong EZH2 expression and high Ki-67 indexes only in epithelioid cells and not in low grade lesions. Univariate analysis demonstrated that abundant epithelioid cells, extensive necrosis, EZH2 overexpression and BRAF V600E mutations were significantly associated with decreased overall survival in EGBM and APXA patients (P < 0.05).

CONCLUSIONS

The results suggested that testing for EZH2 expression and BRAF V600E mutations might be helpful to evaluate the prognoses of EGBM and APXA patients. The presence of heterogeneous EZH2 expression in biphasic EGBMs could also contribute to malignant progression.

microRNA-124a suppresses PHF19 over-expression, EZH2 hyper-activation, and aberrant cell proliferation in human glioma

Enhancer of Zeste 2 (EZH2) is the key enzymatic factor in Polycomb Repressive Complex 2 (PRC2), a transcriptional repressor which contributes to oncogenesis. Recent research has revealed the key role of aberrant EZH2 hyper-activity in human gliomas. Here, we examined the role of the lesser-known PRC2-associated PHD Finger Protein 19 (PHF19) in human glioma. We found that PHF19 transcript and protein levels were significantly elevated in human glioma tumors, which was negatively associated with expression of the anti-PHF19 microRNA miR-124a. miR-124a over-expression in the A172 and U251MG glioma cell lines and patient glioma cells suppressed PHF19 expression, EZH2 activation, and cell proliferation. However, miR-124a did not suppress cell proliferation with PHF19 silencing or mutation. Knockdown of PHF19 suppressed EZH2 phosphorylation and proliferation of glioma cells. Co-immunoprecipitation confirmed that PHF19 forms the PRC2 with EZH2, EED, and SUZ12. In a nude murine model, subcutaneous and orthotopic xenograft tumor growth was significantly inhibited by miRNA-124a or PHF19 shRNA. In conclusion, miR-124a suppresses PHF19 over-expression, EZH2 hyper-activation, and aberrant glioma cell proliferation. Targeting PHF19 via miR-124a agomir therapy may block aberrant EZH2 hyper-activity in these tumors.