Spatial analysis of tissue immunity and vascularity by light sheet fluorescence microscopy

The pathogenesis of cancer and cardiovascular diseases is subjected to spatiotemporal regulation by the tissue microenvironment. Multiplex visualization of the microenvironmental components, including immune cells, vasculature and tissue hypoxia, provides critical information underlying the disease progression and therapy resistance, which is often limited by imaging depth and resolution in large-volume tissues. To this end, light sheet fluorescence microscopy, following tissue clarification and immunostaining, may generate three-dimensional high-resolution images at a whole-organ level. Here we provide a detailed description of light sheet fluorescence microscopy imaging analysis of immune cell composition, vascularization, tissue perfusion and hypoxia in mouse normal brains and hearts, as well as brain tumors. We describe a procedure for visualizing tissue vascularization, perfusion and hypoxia with a transgenic vascular labeling system. We provide the procedures for tissue collection, tissue semi-clearing and immunostaining. We further describe standard methods for analyzing tissue immunity and vascularity. We anticipate that this method will facilitate the spatial illustration of structure and function of the tissue microenvironmental components in cancer and cardiovascular diseases. The procedure requires 1-2 weeks and can be performed by users with expertise in general molecular biology.

Adult brain tumour research in 2024: Status, challenges and recommendations

In 2015, a groundswell of brain tumour patient, carer and charity activism compelled the UK Minister for Life Sciences to form a brain tumour research task and finish group. This resulted, in 2018, with the UK government pledging £20m of funding, to be paralleled with £25m from Cancer Research UK, specifically for neuro-oncology research over the subsequent 5 years. Herein, we review if and how the adult brain tumour research landscape in the United Kingdom has changed over that time and what challenges and bottlenecks remain. We have identified seven universal brain tumour research priorities and three cross-cutting themes, which span the research spectrum from bench to bedside and back again. We discuss the status, challenges and recommendations for each one, specific to the United Kingdom.

Relations Between Posttraumatic Growth and Fear of Progression Among Young and Middle-Aged Primary Brain Tumor Patients: The Parallel Mediating Role of Perceived Social Support and Illness Uncertainty

OBJECTIVE

This study aimed to investigate the mediating role of perceived social support and illness uncertainty in posttraumatic growth (PTG) and fear of progression (FoP) among young and middle-aged primary brain tumor (PBT) patients.

METHODS

A total of 252 young and middle-aged benign PBT patients were investigated. Data were collected by using self-designed general and disease-related data questionnaires, PTG Inventory, FoP Questinaire-Short Form, Mischel Uncertainty in Illness Scale, and Perceived Social Support Scale. Parallel mediation effect models were used to explore the relationship between PTG and FoP mediation effects. Bootstrap analysis was conducted to examine the mediation effect of PTG on FoP.

RESULTS

The total FoP and PTG scores were 35.15 ± 4.85 and 55.04 ± 7.86. Furthermore, mediation effect analyses revealed that perceived social support and illness uncertainty were partially associated with the mediated relationship between PTG and FoP. (std.β = -0.026, P-value = 0.001, std. β = -0.393, P value ＜0.001, respectively).

CONCLUSIONS

Illness uncertainty and perceived social support were identified as partially parallel mediators between PTG and FoP. Thus, we should ensure adequate social support and improve the enthusiasm and input of family members for better patient recovery. Strengthening the nursing support, reducing the uncertainty of young and middle-aged PBT patients, and improving the patients' PTG can help reduce the fear of disease progression.

Multi-parametric MRI-based machine learning model for prediction of WHO grading in patients with meningiomas

OBJECTIVE

The purpose of this study was to develop and validate a nomogram combined multiparametric MRI and clinical indicators for identifying the WHO grade of meningioma.

MATERIALS AND METHODS

Five hundred and sixty-eight patients were included in this study, who were diagnosed pathologically as having meningiomas. Firstly, radiomics features were extracted from CE-T1, T2, and 1-cm-thick tumor-to-brain interface (BTI) images. Then, difference analysis and the least absolute shrinkage and selection operator were orderly used to select the most representative features. Next, the support vector machine algorithm was conducted to predict the WHO grade of meningioma. Furthermore, a nomogram incorporated radiomics features and valuable clinical indicators was constructed by logistic regression. The performance of the nomogram was assessed by calibration and clinical effectiveness, as well as internal validation.

RESULTS

Peritumoral edema volume and gender are independent risk factors for predicting meningioma grade. The multiparametric MRI features incorporating CE-T1, T2, and BTI features showed the higher performance for prediction of meningioma grade with a pooled AUC = 0.885 (95% CI, 0.821-0.946) and 0.860 (95% CI, 0.788-0.923) in the training and test groups, respectively. Then, a nomogram with a pooled AUC = 0.912 (95% CI, 0.876-0.961), combined radiomics score, peritumoral edema volume, and gender improved diagnostic performance compared to radiomics model or clinical model and showed good calibration as the true results. Moreover, decision curve analysis demonstrated satisfactory clinical effectiveness of the proposed nomogram.

CONCLUSIONS

A novel nomogram is simple yet effective in differentiating WHO grades of meningioma and thus can be used in patients with meningiomas.

CLINICAL RELEVANCE STATEMENT

We proposed a nomogram that included clinical indicators and multi-parameter radiomics features, which can accurately, objectively, and non-invasively differentiate WHO grading of meningioma and thus can be used in clinical work.

KEY POINTS

• The study combined radiomics features and clinical indicators for objectively predicting the meningioma grade. • The model with CE-T1 + T2 + brain-to-tumor interface features demonstrated the best predictive performance by investigating seven different radiomics models. • The nomogram potentially has clinical applications in distinguishing high-grade and low-grade meningiomas.

Procedural interventions for oligoprogression during treatment with immune checkpoint blockade in gynecologic malignancies: a case series

OBJECTIVE

To evaluate the feasibility and outcomes of performing procedural interventions, defined as surgical resection, tumor ablation, or targeted radiation therapy, for oligoprogressive disease among patients with gynecologic malignancies who are treated with immune checkpoint blockade.

METHODS

Patients with gynecologic cancers treated with immune checkpoint blockade between January 2013 and October 2021 who underwent procedural interventions including surgical resection, interventional radiology ablation, or radiation therapy for oligoprogressive disease were identified. Procedures performed before immune checkpoint therapy initiation or ≥6 months after therapy completion were excluded. Long immunotherapy duration prior to intervention was defined as ≥6 months. Progression-free survival and overall survival were calculated from procedure date until disease progression or death, respectively.

RESULTS

During the study period, 886 patients met inclusion criteria and received immune checkpoint blockade therapy. Of these, 34 patients underwent procedural interventions for oligoprogressive disease; 7 underwent surgical resection, 3 underwent interventional radiology ablation, and 24 underwent radiation therapy interventions. Primary disease sites included uterus (71%), ovary (24%), and cervix (6%). Sites of oligoprogression included abdomen/pelvis (26%), bone (21%), lung (18%), distant lymph node (18%), brain (9%), liver (6%), and vagina (3%). Most tumors (76%) did not exhibit microsatellite instability or mismatch repair deficiency. Approximately half (53%) of the patients had long immune checkpoint therapy duration prior to intervention. Median progression-free survival following the procedure was 5.3 months (95% CI, 3.1-9.9), and median overall survival was 21.7 months (95% CI, 14.9-not estimable). Long versus short immune checkpoint therapy duration prior to procedure and length of immune checkpoint therapy had no effect on progression-free or overall survival.

CONCLUSIONS

Procedural interventions for patients with oligoprogression on immune checkpoint blockade therapy are feasible and demonstrate favorable outcomes. With expanding use of immune checkpoint therapy, it is important to investigate combined modalities to maximize therapeutic benefit for patients with gynecologic cancers.

Patterns of neurological adverse events among a retrospective cohort of patients receiving immune checkpoint inhibitors

Aim: Neurological adverse events (NAEs) are infrequent immune checkpoint inhibitor (ICI) outcomes poorly characterized in extant research, complicating their clinical management. Methods: This study characterized the frequency, severity, patterning and timing of NAEs using a large retrospective registry, including all patients who received at least one dose of an ICI from 2/1/2011-4/7/2022 within our health network. Results: Among 3137 patients, there were 54 NAEs (1.72% any grade; 0.8% grade 3-4). Most NAEs were peripheral (57.4%) versus central (42.6%). Melanoma and renal cell carcinoma were significantly associated with NAEs. Conclusion: The incidence of NAEs was rare though higher than many prior case estimates; the timing was consistent with other AEs. NAEs frequently occurred in tumor types known to favor brain metastases.

Tumor analysis of MMR genes in Lynch-like syndrome: Challenges associated with results interpretation

BACKGROUND

Up to 70% of suspected Lynch syndrome patients harboring MMR deficient tumors lack identifiable germline pathogenic variants in MMR genes, being referred to as Lynch-like syndrome (LLS). Previous studies have reported biallelic somatic MMR inactivation in a variable range of LLS-associated tumors. Moreover, translating tumor testing results into patient management remains controversial. Our aim is to assess the challenges associated with the implementation of tumoral MMR gene testing in routine workflows.

METHODS

Here, we present the clinical characterization of 229 LLS patients. MMR gene testing was performed in 39 available tumors, and results were analyzed using two variant allele frequency (VAF) thresholds (≥5% and ≥10%).

RESULTS AND DISCUSSION

More biallelic somatic events were identified at VAF ≥ 5% than ≥10% (35.9% vs. 25.6%), although the rate of nonconcordant results regarding immunohistochemical pattern increased (30.8% vs. 20.5%). Interpretation difficulties question the current utility of the identification of MMR somatic hits in the diagnostic algorithm of suspected LS cases.

BRAFV600E immunohistochemistry can reliably substitute BRAF molecular testing in the Lynch syndrome screening algorithm in colorectal cancer

AIMS

The Lynch syndrome (LS) screening algorithm requires BRAF testing as a fundamental step to distinguish sporadic from LS-associated colorectal carcinomas (CRC). BRAF testing by immunohistochemistry (IHC) has shown variable results in the literature. Our aim was to analyse concordance between BRAFV600E IHC and BRAF molecular analysis in a large, mono-institutional CRC whole-slide, case series with laboratory validation.

METHODS AND RESULTS

MisMatch repair (MMR) protein (hMLH1, hPMS2, hMSH2, and hMSH6) and BRAFV600E IHC were performed on all unselected cases of surgically resected CRCs (2018-2023). An in-house validation study for BRAFV600E IHC was performed in order to obtain optimal IHC stains. BRAFVV600E IHC was considered negative (score 0), positive (scores 2-3), and equivocal (score 1). Interobserver differences in BRAFV600E IHC scoring were noted in the first 150 cases prospectively collected. Nine-hundred and ninety CRCs cases (830 proficient (p)MMR/160 deficient (d)MMR) were included and all cases performed BRAFV600E IHC (BRAFV600E IHC-positive 13.5% of all series; 66.3% dMMR cases; 3.4% pMMR cases), while 333 also went to BRAF mutation analysis. Optimal agreement in IHC scoring between pathologists (P < 0.0001) was seen; concordance between BRAFV600E IHC and BRAF molecular analysis was extremely high (sensitivity 99.1%, specificity 99.5%; PPV 99.1%, and NPV 99.5%). Discordant cases were reevaluated; 1 score 3 + IHC/wildtype case was an interpretation error and one score 0 IHC/mutated case was related to heterogenous BRAFV600E IHC expression. Among the 12 IHC-equivocal score 1+ cases (which require BRAF molecular analysis), three were BRAF-mutated and nine BRAF-wildtype.

CONCLUSION

BRAFV600E IHC can be used as a reliable surrogate of molecular testing after stringent in-house validation.

Real-world study on microsatellite instability and mismatch repair deficiency testing patterns among patients with metastatic colorectal cancer in Spain

PURPOSE

Clinical practice guidelines recommend that all patients with metastatic colorectal cancer (mCRC) should be tested for mismatch repair deficiency (dMMR) or microsatellite instability-high (MSI-H). We aimed to describe the dMMR/MSI-H testing practice in patients with mCRC in Spanish centers.

METHODS

Multicenter, observational retrospective study that included patients newly diagnosed with mCRC or who progressed to a metastatic stage from early/localized stages.

RESULTS

Three hundred patients were included in the study from May 2020 through May 2021, with a median age of 68 years, and two hundred twenty-five (75%) had stage IV disease at initial diagnosis; two hundred eighty-four patients received first-line treatment, and dMMR/MSI-H testing was performed in two hundred fifty-one (84%) patients. The results of the dMMR/MSI-H tests were available in 61 (24%) of 251 patients before the diagnosis of metastatic disease and in 191 (81%) of 236 evaluable patients for this outcome before the initiation of first-line treatment. Among the 244 patients who were tested for dMMR/MSI-H with IHC or PCR, 14 (6%) were MMR deficient. The most frequent type of first-line treatment was the combination of chemotherapy and biological agent, that was received by 71% and 50% of patients with MMR proficient and deficient tumors, respectively, followed by chemotherapy alone, received in over 20% of patients in each subgroup. Only 29% of dMMR/MSI-H tumors received first-line immunotherapy.

CONCLUSION

Our study suggests that a high proportion of patients with mCRC are currently tested for dMMR/MSI-H in tertiary hospitals across Spain. However, there is still room for improvement until universal testing is achieved.

TRIAL REGISTRATION

Not applicable.

A Panel-Based Mutational Signature of Mismatch Repair Deficiency is Associated With Durable Response to Pembrolizumab in Metastatic Castration-Resistant Prostate Cancer

INTRODUCTION/BACKGROUND

Immune checkpoint inhibitors (ICIs) have limited efficacy in prostate cancer (PCa). Better biomarkers are needed to predict responses to ICIs. We sought to demonstrate that a panel-based mutational signature identifies mismatch repair (MMR) deficient (MMRd) PCa and is a biomarker of response to pembrolizumab.

PATIENTS AND METHODS

Clinico-genomic data was obtained for 2664 patients with PCa sequenced at Dana-Farber Cancer Institute (DFCI) and Memorial Sloan Kettering (MSK). Clinical outcomes were collected for patients with metastatic castration-resistant PCa (mCRPC) treated with pembrolizumab at DFCI. SigMA was used to characterize tumors as MMRd or MMR proficient (MMRp). The concordance between MMRd with microsatellite instability (MSI-H) was assessed. Radiographic progression-free survival (rPFS) and overall survival (OS) were collected for patients treated with pembrolizumab. Event-time distributions were estimated using Kaplan-Meier methodology.

RESULTS

Across both cohorts, 100% (DFCI: 12/12; MSK: 43/43) of MSI-H tumors were MMRd. However, 14% (2/14) and 9.1% (6/66) of MMRd tumors in the DFCI and MSK cohorts respectively were microsatellite stable (MSS), and 26% (17/66) were MSI-indeterminate in the MSK cohort. Among patients treated with pembrolizumab, those with MMRd (n = 5) versus MMRp (n = 14) mCRPC experienced markedly improved rPFS (HR = 0.088, 95% CI: 0.011-0.70; P = .0064) and OS (HR = 0.11, 95% CI: 0.014-0.80; P = .010) from start of treatment. Four patients with MMRd experienced remissions of >= 2.5 years.

CONCLUSION

SigMA detects additional cases of MMRd as compared to MSI testing in PCa and identifies patients likely to experience durable response to pembrolizumab.

Targeting Group 3 Medulloblastoma by the Anti-PRUNE-1 and Anti-LSD1/KDM1A Epigenetic Molecules

Medulloblastoma (MB) is a highly malignant childhood brain tumor. Group 3 MB (Gr3 MB) is considered to have the most metastatic potential, and tailored therapies for Gr3 MB are currently lacking. Gr3 MB is driven by PRUNE-1 amplification or overexpression. In this paper, we found that PRUNE-1 was transcriptionally regulated by lysine demethylase LSD1/KDM1A. This study aimed to investigate the therapeutic potential of inhibiting both PRUNE-1 and LSD1/KDM1A with the selective inhibitors AA7.1 and SP-2577, respectively. We found that the pharmacological inhibition had a substantial efficacy on targeting the metastatic axis driven by PRUNE-1 (PRUNE-1-OTX2-TGFβ-PTEN) in Gr3 MB. Using RNA seq transcriptomic feature data in Gr3 MB primary cells, we provide evidence that the combination of AA7.1 and SP-2577 positively affects neuronal commitment, confirmed by glial fibrillary acidic protein (GFAP)-positive differentiation and the inhibition of the cytotoxic components of the tumor microenvironment and the epithelial-mesenchymal transition (EMT) by the down-regulation of N-Cadherin protein expression. We also identified an impairing action on the mitochondrial metabolism and, consequently, oxidative phosphorylation, thus depriving tumors cells of an important source of energy. Furthermore, by overlapping the genomic mutational signatures through WES sequence analyses with RNA seq transcriptomic feature data, we propose in this paper that the combination of these two small molecules can be used in a second-line treatment in advanced therapeutics against Gr3 MB. Our study demonstrates that the usage of PRUNE-1 and LSD1/KDM1A inhibitors in combination represents a novel therapeutic approach for these highly aggressive metastatic MB tumors.

Identification and validation of a metabolism-related gene signature for predicting the prognosis of paediatric medulloblastoma

Medulloblastoma (MB) is a malignant brain tumour that is highly common in children and has a tendency to spread to the brain and spinal cord. MB is thought to be a metabolically driven brain tumour. Understanding tumour cell metabolic patterns and characteristics can provide a promising foundation for understanding MB pathogenesis and developing treatments. Here, by analysing RNA-seq data of MB samples from the Gene Expression Omnibus (GEO) database, 12 differentially expressed metabolic-related genes (DE-MRGs) were chosen for the construction of a predictive risk score model for MB. This model demonstrated outstanding accuracy in predicting the outcomes of MB patients and served as a standalone predictor. An evaluation of functional enrichment revealed that the risk score showed enrichment in pathways related to cancer promotion and the immune response. In addition, a high risk score was an independent poor prognostic factor for MB in patients with different ages, sexes, metastasis stages and subgroups (SHH and Group 4). Consistently, the metabolic enzyme ornithine decarboxylase (ODC1) was upregulated in MB patients with poor survival time. Inhibition of ODC1 in primary and metastatic MB cell lines decreased cell proliferation, migration and invasion but increased immune infiltration. This study could aid in identifying metabolic targets for MB as well as optimizing risk stratification systems and individual treatment plans for MB patients via the use of a metabolism-related gene prognostic risk score signature.

The HLA-I landscape confers prognosis and antitumor immunity in breast cancer

Breast cancer is a highly heterogeneous disease with varied subtypes, prognoses and therapeutic responsiveness. Human leukocyte antigen class I (HLA-I) shapes the immunity and thereby influences the outcome of breast cancer. However, the implications of HLA-I variations in breast cancer remain poorly understood. In this study, we established a multiomics cohort of 1156 Chinese breast cancer patients for HLA-I investigation. We calculated four important HLA-I indicators in each individual, including HLA-I expression level, somatic HLA-I loss of heterozygosity (LOH), HLA-I evolutionary divergence (HED) and peptide-binding promiscuity (Pr). Then, we evaluated their distribution and prognostic significance in breast cancer subtypes. We found that the four breast cancer subtypes had distinct features of HLA-I indicators. Increased expression of HLA-I and LOH were enriched in triple-negative breast cancer (TNBC), while Pr was relatively higher in hot tumors within TNBCs. In particular, a higher Pr indicated a better prognosis in TNBCs by regulating the infiltration of immune cells and the expression of immune molecules. Using the matched genomic and transcriptomic data, we found that mismatch repair deficiency-related mutational signature and pathways were enriched in low-Pr TNBCs, suggesting that targeting mismatch repair deficiency for synthetic lethality might be promising therapy for these patients. In conclusion, we presented an overview of HLA-I indicators in breast cancer and provided hints for precision treatment for low-Pr TNBCs.

Research on multi-model imaging machine learning for distinguishing early hepatocellular carcinoma

OBJECTIVE

To investigate the value of differential diagnosis of hepatocellular carcinoma (HCC) and non-hepatocellular carcinoma (non-HCC) based on CT and MR multiphase radiomics combined with different machine learning models and compare the diagnostic efficacy between different radiomics models.

BACKGROUND

Primary liver cancer is one of the most common clinical malignancies, hepatocellular carcinoma (HCC) is the most common subtype of primary liver cancer, accounting for approximately 90% of cases. A clear diagnosis of HCC is important for the individualized treatment of patients with HCC. However, more sophisticated diagnostic modalities need to be explored.

METHODS

This retrospective study included 211 patients with liver lesions: 97 HCC and 124 non-hepatocellular carcinoma (non-HCC) who underwent CT and MRI. Imaging data were used to obtain imaging features of lesions and radiomics regions of interest (ROI). The extracted imaging features were combined to construct different radiomics models. The clinical data and imaging features were then combined with radiomics features to construct the combined models. Support Vector Machine (SVM), K-nearest Neighbor (KNN), RandomForest (RF), eXtreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), Multilayer Perceptron (MLP) six machine learning models were used for training. Five-fold cross-validation was used to train the models, and ROC curves were used to analyze the diagnostic efficacy of each model and calculate the accuracy rate. Model training and efficacy test were performed as before.

RESULTS

Statistical analysis showed that some clinical data (gender and concomitant cirrhosis) and imaging features (presence of envelope, marked enhancement in the arterial phase, rapid contouring in the portal phase, uniform density/signal and concomitant steatosis) were statistical differences (P < 0.001). The results of machine learning models showed that KNN had the best diagnostic efficacy. The results of the combined model showed that SVM had the best diagnostic efficacy, indicating that the combined model (accuracy 0.824) had better diagnostic efficacy than the radiomics-only model.

CONCLUSIONS

Our results demonstrate that the radiomic features of CT and MRI combined with machine learning models enable differential diagnosis of HCC and non-HCC (malignant, benign). The diagnostic model with dual radiomic had better diagnostic efficacy. The combined model was superior to the radiomic model alone.

Outcomes of Patients with Non-Small Cell Lung Cancer and Brain Metastases Treated with the Upfront Single Agent Pembrolizumab: A Retrospective and Multicentric Study of the ESCKEYP GFPC Cohort

Non-small cell lung cancer (NSCLC) is the most common cause of brain metastasis (BM). Little is known about immune checkpoint inhibitor activity in the central nervous system, especially in patients receiving monotherapy for tumors with a tumor proportion score (TPS) ≥ 50%. This noninterventional, retrospective, multicenter study, conducted with the GFPC, included treatment-naïve patients strongly positive for PD-L1 (TPS ≥ 50%) with BM receiving first-line single-agent pembrolizumab treatment between May 2017 and November 2019. The primary endpoints were centrally reviewed intracranial overall response rates (ORRs), centrally reviewed intracranial progression-free survival (cPFS), extracranial PFS, and overall survival were secondary endpoints. Forty-three patients from five centers were included. Surgical or local radiation therapy was administered to 31 (72%) patients, mostly before initiating ICI therapy (25/31). Among 38/43 (88.4%) evaluable patients, the intracranial ORR was 73%. The median PFS was 8.3 months. The cerebral and extracerebral median PFS times were 9.2 and 5.3 months, respectively. The median OS was 25.5 months. According to multivariate analysis, BM surgery before ICI therapy was the only factor significantly associated with both improved PFS (HR = 0.44) and OS (HR = 0.45). This study revealed the feasibility and outcome of front-line pembrolizumab treatment in this population with BM.

Gastroesophageal Adenocarcinomas With Defective Mismatch Repair: Current Knowledge and Clinical Management

Esophageal, gastroesophageal junction, and gastric adenocarcinomas, referred to collectively as gastroesophageal adenocarcinomas (GEAs), are a major cause of global cancer-related mortality. Our increasing molecular understanding has led to the addition of biomarker-directed approaches to defined subgroups and has improved survival in selected patients, such as those with HER2 and Claudin18.2 overexpression. Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of cancer, including GEA, but biomarkers beyond PD-L1 expression are lacking. Mismatch repair deficiency and/or high microsatellite instability (dMMR/MSI-H) is observed in 8% to 22% of nonmetastatic GEA, and 3% to 5% of patients with metastatic disease. dMMR/MSI-H tumors are associated with more favorable prognosis and significant benefit from ICIs, although some heterogeneity exists. The activity of ICIs in advanced dMMR/MSI-H cancer is seen across lines of therapy and should be recommended in the frontline setting. In patients with nonmetastatic dMMR/MSI-H cancer, increasing evidence suggests that perioperative and adjuvant chemotherapy may not provide benefit to the dMMR/MSI-H subgroup. The activity of perioperative chemotherapy-free immune checkpoint regimens in patients with nonmetastatic dMMR/MSI-H cancer is highly promising and underscores the need to identify this unique subgroup. We recommend MMR/MSI testing for all patients with GEA at diagnosis, and review the key rationale and clinical management implications for patient with dMMR/MSI-H tumors across disease stages.

Epigenetic MLH1 silencing concurs with mismatch repair deficiency in sporadic, naturally occurring colorectal cancer in rhesus macaques

BACKGROUND

Naturally occurring colorectal cancers (CRC) in rhesus macaques share many features with their human counterparts and are useful models for cancer immunotherapy; but mechanistic data are lacking regarding the comparative molecular pathogenesis of these cancers.

METHODS

We conducted state-of-the-art imaging including CT and PET, clinical assessments, and pathological review of 24 rhesus macaques with naturally occurring CRC. Additionally, we molecularly characterized these tumors utilizing immunohistochemistry (IHC), microsatellite instability assays, DNAseq, transcriptomics, and developed a DNA methylation-specific qPCR assay for MLH1, CACNA1G, CDKN2A, CRABP1, and NEUROG1, human markers for CpG island methylator phenotype (CIMP). We furthermore employed Monte-Carlo simulations to in-silico model alterations in DNA topology in transcription-factor binding site-rich promoter regions upon experimentally demonstrated DNA methylation.

RESULTS

Similar cancer histology, progression patterns, and co-morbidities could be observed in rhesus as reported for human CRC patients. IHC identified loss of MLH1 and PMS2 in all cases, with functional microsatellite instability. DNA sequencing revealed the close genetic relatedness to human CRCs, including a similar mutational signature, chromosomal instability, and functionally-relevant mutations affecting KRAS (G12D), TP53 (R175H, R273*), APC, AMER1, ALK, and ARID1A. Interestingly, MLH1 mutations were rarely identified on a somatic or germline level. Transcriptomics not only corroborated the similarities of rhesus and human CRCs, but also demonstrated the significant downregulation of MLH1 but not MSH2, MSH6, or PMS2 in rhesus CRCs. Methylation-specific qPCR suggested CIMP-positivity in 9/16 rhesus CRCs, but all 16/16 exhibited significant MLH1 promoter hypermethylation. DNA hypermethylation was modelled to affect DNA topology, particularly propeller twist and roll profiles. Modelling the DNA topology of a transcription factor binding motif (TFAP2A) in the MLH1 promoter that overlapped with a methylation-specific probe, we observed significant differences in DNA topology upon experimentally shown DNA methylation. This suggests a role of transcription factor binding interference in epigenetic silencing of MLH1 in rhesus CRCs.

CONCLUSIONS

These data indicate that epigenetic silencing suppresses MLH1 transcription, induces the loss of MLH1 protein, abrogates mismatch repair, and drives genomic instability in naturally occurring CRC in rhesus macaques. We consider this spontaneous, uninduced CRC in immunocompetent, treatment-naïve rhesus macaques to be a uniquely informative model for human CRC.

A Benzarone Derivative Inhibits EYA to Suppress Tumor Growth in SHH Medulloblastoma

Medulloblastoma is one of the most common malignant brain tumors of children, and 30% of medulloblastomas are driven by gain-of-function genetic lesions in the Sonic Hedgehog (SHH) signaling pathway. EYA1, a haloacid dehalogenase phosphatase and transcription factor, is critical for tumorigenesis and proliferation of SHH medulloblastoma (SHH-MB). Benzarone and benzbromarone have been identified as allosteric inhibitors of EYA proteins. Using benzarone as a point of departure, we developed a panel of 35 derivatives and tested them in SHH-MB. Among these compounds, DS-1-38 functioned as an EYA antagonist and opposed SHH signaling. DS-1-38 inhibited SHH-MB growth in vitro and in vivo, showed excellent brain penetrance, and increased the lifespan of genetically engineered mice predisposed to fatal SHH-MB. These data suggest that EYA inhibitors represent promising therapies for pediatric SHH-MB.

SIGNIFICANCE

Development of a benzarone derivative that inhibits EYA1 and impedes the growth of SHH medulloblastoma provides an avenue for improving treatment of this malignant pediatric brain cancer.

Facilitating Repeat Intracarotid Injections in Mouse Models by a Novel Injection Site Repair Technique

Given recent advances in the delivery of novel antitumor therapeutics using endovascular selective intraarterial delivery methods in neuro-oncology, there is an urgent need to develop methods for intracarotid injections in mouse models, including methods to repair the carotid artery in mice after injection to allow for subsequent injections. We developed a method of intracarotid injection in a mouse model to deliver therapeutics into the internal carotid artery (ICA) with two alternative procedures. During injection, the needle is inserted into the common carotid artery (CCA) after tying a suture around the external carotid artery (ECA) and injected therapeutics are delivered into the ICA. Following injection, the common carotid artery (CCA) can be ligated, which limits the number of intracarotid injections to one. The alternative procedure described in this article includes a modification where intracarotid artery injection is followed by injection site repair of the CCA, which restores blood flow within the CCA and avoids the complication of cerebral ischemia seen in some mouse models. We also compared the delivery of bone marrow-derived human mesenchymal stem cells (BM-hMSCs) to intracranial tumors when delivered through intracarotid injection with and without injection site repair following the injection. Delivery of BM-hMSCs does not differ significantly between the methods. Our results demonstrate that injection site repair of the CCA allows for repeat injections through the same artery and does not impair the delivery and distribution of injected material, thus providing a model with greater flexibility that more closely emulates intracarotid injection in humans.

Serum Interleukin-38 and Tumor-Infiltrating Lymphocytes in Primary Brain Tumors

Background

Tumor-infiltrating lymphocytes (TILs) and brain stromal cells produce immunosuppressive cytokines, contributing to an immunosuppressive tumor microenvironment (TME). Interleukin-38 (IL-38) is a novel anti-inflammatory cytokine and a natural modulator of the innate and adaptive immune system. However, its biological roles in brain tumors are not well defined.

Objective

To assess the serum levels of IL-38 and the percentages of TILs in the tumor tissues of patients with primary brain tumors and to determine their associations with the pathological features of the disease.

Methods

IL-38 was evaluated in sera using the enzyme-linked immunosorbent assay (ELISA). Hematoxylin and eosin (H&E)-stained sections were scored to determine the percentages of TILs in four different areas: the invasive margin, central tumor, perivascular and perinecrotic areas.

Results

IL-38 serum levels were significantly higher in low- and high-grade tumors than in healthy individuals, meanwhile, its levels remained consistent between these two grades. Although no significant difference was found in IL-38 serum levels between different histological subtypes of brain tumors, its levels were significantly higher in intra-axial brain tumors than in extra-axial ones. Additionally, a significant positive correlation was observed between serum levels of IL-38 and tumor size in patients with low-grade tumors. TILs were detected in at least one of the four examined areas; however, no statistically significant correlation was found between IL-38 levels and TILs.

Conclusion

Our data may suggest a connection between IL-38 and immune suppression and tumor progression in primary brain tumors. Further investigation is needed to uncover the role of IL-38 in the brain tumor microenvironment.

The first pineoblastoma case report of a patient with Sotos syndrome harboring NSD1 germline mutation

Germline mutations of NSD1 are associated with Sotos syndrome, characterized by distinctive facial features, overgrowth, and developmental delay. Approximately 3% of individuals with Sotos syndrome develop tumors. In this study, we describe an infant in pineoblastoma with facial anomalies, learning disability and mild autism at 1 years diagnosed as Sotos syndrome owing to carrying a novel mutation de novo germline NSD1 likely pathogenic variant. This patient expands both the mutation and phenotype spectrum of the Sotos Syndrome and provides new clinical insights into the potential mechanism of underlying pinealoblastoma pathology.

Label-free nonlinear optical signatures of extracellular vesicles in liquid and tissue biopsies of human breast cancer

Extracellular vesicles (EVs) have been implicated in metastasis and proposed as cancer biomarkers. However, heterogeneity and small size makes assessments of EVs challenging. Often, EVs are isolated from biofluids, losing spatial and temporal context and thus lacking the ability to access EVs in situ in their native microenvironment. This work examines the capabilities of label-free nonlinear optical microscopy to extract biochemical optical metrics of EVs in ex vivo tissue and EVs isolated from biofluids in cases of human breast cancer, comparing these metrics within and between EV sources. Before surgery, fresh urine and blood serum samples were obtained from human participants scheduled for breast tumor surgery (24 malignant, 6 benign) or healthy participants scheduled for breast reduction surgery (4 control). EVs were directly imaged both in intact ex vivo tissue that was removed during surgery and in samples isolated from biofluids by differential ultracentrifugation. Isolated EVs and freshly excised ex vivo breast tissue samples were imaged with custom nonlinear optical microscopes to extract single-EV optical metabolic signatures of NAD(P)H and FAD autofluorescence. Optical metrics were significantly altered in cases of malignant breast cancer in biofluid-derived EVs and intact tissue EVs compared to control samples. Specifically, urinary isolated EVs showed elevated NAD(P)H fluorescence lifetime in cases of malignant cancer, serum-derived isolated EVs showed decreased optical redox ratio in stage II cancer, but not earlier stages, and ex vivo breast tissue showed an elevated number of EVs in cases of malignant cancer. Results further indicated significant differences in the measured optical metabolic signature based on EV source (urine, serum and tissue) within individuals.

Identification of Key Molecular Pathways and Associated Genes as Targets to Overcome Radiotherapy Resistance Using a Combination of Radiotherapy and Immunotherapy in Glioma Patients

Recent mechanistic studies have indicated that combinations of radiotherapy (RT) plus immunotherapy (via CSF-1R inhibition) can serve as a strategy to overcome RT resistance and improve the survival of glioma mice. Given the high mortality rate for glioma, including low-grade glioma (LGG) patients, it is of critical importance to investigate the mechanism of the combination of RT and immunotherapy and further translate the mechanism from mouse studies to improve survival of RT-treated human glioma patients. Using the RNA-seq data from a glioma mouse study, 874 differentially expressed genes (DEGs) between the group of RT-treated mice at glioma recurrence and the group of mice with combination treatment (RT plus CSF-1R inhibition) were translated to the human genome to identify significant molecular pathways using the KEGG enrichment analysis. The enrichment analysis yields statistically significant signaling pathways, including the phosphoinositide 3-kinase (PI3K)/AKT pathway, Hippo pathway, and Notch pathway. Within each pathway, a candidate gene set was selected by Cox regression models as genetic biomarkers for resistance to RT and response to the combination of RT plus immunotherapies. Each Cox model is trained using a cohort of 295 RT-treated LGG patients from The Cancer Genome Atlas (TCGA) database and validated using a cohort of 127 RT-treated LGG patients from the Chinese Glioma Genome Atlas (CGGA) database. A four-DEG signature (ITGB8, COL9A3, TGFB2, JAG1) was identified from the significant genes within the three pathways and yielded the area under time-dependent ROC curve AUC = 0.86 for 5-year survival in the validation set, which indicates that the selected DEGs have strong prognostic value and are potential intervention targets for combination therapies. These findings may facilitate future trial designs for developing combination therapies for glioma patients.