The clinical significance of sub-total surgical resection in childhood medulloblastoma: a multi-cohort analysis of 1100 patients

Background

Medulloblastoma patients with a sub-total surgical resection (STR; >1.5 cm2 primary tumour residuum post-surgery) typically receive intensified treatment. However, the association of STR with poor outcomes has not been observed consistently, questioning the validity of STR as a high-risk disease feature.

Methods

We collected extent of resection (EOR) data from 1110 patients (from UK CCLG centres (n = 416, collected between September 1990 and July 2014) and published (n = 694) cohorts), the largest cohort of molecularly and clinically annotated tumours assembled to specifically assess the significance of EOR. We performed association and univariable/multivariable survival analyses, assessing overall survival (OS) cohort-wide and with reference to the four consensus medulloblastoma molecular groups and clinical features.

Findings

STR was reported in 20% (226/1110) of patients. Non-WNT (p = 0.047), children <5 years at diagnosis (p = 0.021) and metastatic patients (p < 0.0001) were significantly more likely to have a STR. In cohort-wide analysis, STR was associated with worse survival in univariable analysis (p < 0.0001). Examination of specific disease contexts showed that STR was prognostic in univariate analysis for patients receiving cranio-spinal irradiation (CSI) and chemotherapy (p = 0.016) and for patients with Group 3 tumours receiving CSI (p = 0.039). STR was not independently prognostic in multivariable analyses; outcomes for patients who have STR as their only risk-feature are as per standard-risk disease. Specifically, STR was not prognostic in non-metastatic patients that received upfront CSI.

Interpretation

In a cohort of 1100 molecularly characterised medulloblastoma patients, STR (n = 226) predicted significantly lower OS in univariable analysis, but was not an independent prognostic factor. Our data suggest that maximal safe resection can continue to be carried out for patients with medulloblastoma and suggest STR should not inform patient management when observed as a sole, isolated risk-feature.

Funding

Cancer Research UK, Newcastle Hospitals Charity, Children's Cancer North, British Division of the International Academy of Pathology.

Metabolite profiles of medulloblastoma for rapid and non-invasive detection of molecular disease groups

BACKGROUND

The malignant childhood brain tumour, medulloblastoma, is classified clinically into molecular groups which guide therapy. DNA-methylation profiling is the current classification 'gold-standard', typically delivered 3-4 weeks post-surgery. Pre-surgery non-invasive diagnostics thus offer significant potential to improve early diagnosis and clinical management. Here, we determine tumour metabolite profiles of the four medulloblastoma groups, assess their diagnostic utility using tumour tissue and potential for non-invasive diagnosis using in vivo magnetic resonance spectroscopy (MRS).

METHODS

Metabolite profiles were acquired by high-resolution magic-angle spinning NMR spectroscopy (MAS) from 86 medulloblastomas (from 59 male and 27 female patients), previously classified by DNA-methylation array (WNT (n = 9), SHH (n = 22), Group3 (n = 21), Group4 (n = 34)); RNA-seq data was available for sixty. Unsupervised class-discovery was performed and a support vector machine (SVM) constructed to assess diagnostic performance. The SVM classifier was adapted to use only metabolites (n = 10) routinely quantified from in vivo MRS data, and re-tested. Glutamate was assessed as a predictor of overall survival.

FINDINGS

Group-specific metabolite profiles were identified; tumours clustered with good concordance to their reference molecular group (93%). GABA was only detected in WNT, taurine was low in SHH and lipids were high in Group3. The tissue-based metabolite SVM classifier had a cross-validated accuracy of 89% (100% for WNT) and, adapted to use metabolites routinely quantified in vivo, gave a combined classification accuracy of 90% for SHH, Group3 and Group4. Glutamate predicted survival after incorporating known risk-factors (HR = 3.39, 95% CI 1.4-8.1, p = 0.025).

INTERPRETATION

Tissue metabolite profiles characterise medulloblastoma molecular groups. Their combination with machine learning can aid rapid diagnosis from tissue and potentially in vivo. Specific metabolites provide important information; GABA identifying WNT and glutamate conferring poor prognosis.

FUNDING

Children with Cancer UK, Cancer Research UK, Children's Cancer North and a Newcastle University PhD studentship.

Molecular characterisation defines clinically-actionable heterogeneity within Group 4 medulloblastoma and improves disease risk-stratification

Group 4 tumours (MBGrp4) represent the majority of non-WNT/non-SHH medulloblastomas. Their clinical course is poorly predicted by current risk-factors. MBGrp4 molecular substructures have been identified (e.g. subgroups/cytogenetics/mutations), however their inter-relationships and potential to improve clinical sub-classification and risk-stratification remain undefined. We comprehensively characterised the paediatric MBGrp4 molecular landscape and determined its utility to improve clinical management. A clinically-annotated discovery cohort (n = 362 MBGrp4) was assembled from UK-CCLG institutions and SIOP-UKCCSG-PNET3, HIT-SIOP-PNET4 and PNET HR + 5 clinical trials. Molecular profiling was undertaken, integrating driver mutations, second-generation non-WNT/non-SHH subgroups (1-8) and whole-chromosome aberrations (WCAs). Survival models were derived for patients ≥ 3 years of age who received contemporary multi-modal therapies (n = 323). We first independently derived and validated a favourable-risk WCA group (WCA-FR) characterised by ≥ 2 features from chromosome 7 gain, 8 loss, and 11 loss. Remaining patients were high-risk (WCA-HR). Subgroups 6 and 7 were enriched for WCA-FR (p < 0·0001) and aneuploidy. Subgroup 8 was defined by predominantly balanced genomes with isolated isochromosome 17q (p < 0·0001). While no mutations were associated with outcome and overall mutational burden was low, WCA-HR harboured recurrent chromatin remodelling mutations (p = 0·007). Integration of methylation and WCA groups improved risk-stratification models and outperformed established prognostication schemes. Our MBGrp4 risk-stratification scheme defines: favourable-risk (non-metastatic disease and (i) subgroup 7 or (ii) WCA-FR (21% of patients, 5-year PFS 97%)), very-high-risk (metastatic disease with WCA-HR (36%, 5-year PFS 49%)) and high-risk (remaining patients; 43%, 5-year PFS 67%). These findings validated in an independent MBGrp4 cohort (n = 668). Importantly, our findings demonstrate that previously established disease-wide risk-features (i.e. LCA histology and MYC(N) amplification) have little prognostic relevance in MBGrp4 disease. Novel validated survival models, integrating clinical features, methylation and WCA groups, improve outcome prediction and re-define risk-status for ~ 80% of MBGrp4. Our MBGrp4 favourable-risk group has MBWNT-like excellent outcomes, thereby doubling the proportion of medulloblastoma patients who could benefit from therapy de-escalation approaches, aimed at reducing treatment induced late-effects while sustaining survival outcomes. Novel approaches are urgently required for the very-high-risk patients.

Medulloblastoma group 3 and 4 tumors comprise a clinically and biologically significant expression continuum reflecting human cerebellar development

Medulloblastoma is currently subclassified into distinct DNA methylation subgroups/subtypes with particular clinico-molecular features. Using RNA sequencing (RNA-seq) in large, well-annotated cohorts of medulloblastoma, we show that transcriptionally group 3 and group 4 medulloblastomas exist as intermediates on a bipolar continuum between archetypal group 3 and group 4 entities. Continuum position is prognostic, reflecting a propensity for specific DNA copy-number changes, and specific switches in isoform/enhancer usage and RNA editing. Examining single-cell RNA-seq (scRNA-seq) profiles, we show that intratumoral transcriptional heterogeneity along the continuum is limited in a subtype-dependent manner. By integrating with a human scRNA-seq reference atlas, we show that this continuum is mirrored by an equivalent continuum of transcriptional cell types in early fetal cerebellar development. We identify distinct developmental niches for all four major subgroups and link each to a common developmental antecedent. Our findings show a transcriptional continuum arising from oncogenic disruption of highly specific fetal cerebellar cell types, linked to almost every aspect of group 3/group 4 molecular biology and clinico-pathology.

MEDB-65. Molecular subclassification of a national cohort of pediatric medulloblastoma based on methylation profile

INTRODUCTION: Pediatric Medulloblastoma (MB) accounts for approximately 20% of all childhood brain tumors. Molecular subgroups namely WNT, SHH, Group 3 and Group 4, exhibit divergent biology, and clinical outcomes. DNA methylation analysis is a robust option to classify pediatric MB into molecular subgroups, which allows the optimization of diagnosis and stratification of the treatment. We review the first experience of molecular subclassification carried out at the national level in our country. METHODS: Multi-center centralized prospective and retrospective study of frozen tumor samples at diagnosis from pediatric MB patients diagnosed in Spanish hospitals, from April 2021 to December 2021. A registry was created with histology review, immunohistochemical (IHC) subgrouping, and a molecular subgrouping based on the Minimal Methylation Classifier (MIMIC) from Schwalbe et al., 2017. The time from the sample centralized reception to the study result was also collected. RESULTS: 25 frozen MB tumor samples from patients at diagnosis were included. 6 were retrospective and 19 prospective. IHC classified 19 cases (76%) as non-WNT/non-SHH MBs, 3 (12%) as WNT-activated and 3 (12%) as SHH-activated. MIMIC classified, in the non-WNT/non-SHH, 6 tumors (24%) as Group 3 and 13 (52%) as Group 4. 2 cases (8%) were WNT-activated MBs and 3 (12%) were SHH-activated MBs. Only 1 case (4%) was unclassified by MIMIC (WNT using IHC). Comparing both methods (IHC and MIMIC), diagnosis agreed in 96% of cases. The response time ranged from 5 to 10 days. CONCLUSIONS: DNA methylation profiling has proven to be a robust and quick option to classify MB into subgroups and it correlates with the IHC diagnosis. This tool was successfully implemented in our national routine diagnosis, enabling a reliable and rapid molecular subgrouping classification.

MEDB-71. Molecular characterisation of group 4 medulloblastoma improves risk-stratification and its biological understanding

Group 4 (MB_Grp4) accounts for ~40% of medulloblastoma and the majority of non-WNT/non-SHH cases, yet its underpinning biology is poorly understood, and survival outcomes are not sufficiently explained by established clinico-pathological risk factors. We investigated the clinical and molecular correlates of MB_Grp4, including second-generation methylation non-WNT/non-SHH subtypes (I-VIII) and whole chromosome aberration (WCA) subtypes (defined by chromosome 7 gain, 8 loss, and 11 loss; WCA-favourable risk [WCA-FR] ≥2 features, WCA-high risk [WCA-HR] ≤1 feature). A clinically-annotated MB_Grp4 discovery cohort (n=378) was assembled from UK CCLG institutions, collaborating centres and SIOP-UKCCSG-PNET3/HIT-SIOP-PNET4 clinical trials. Contemporary molecular profiling integrating methylation/WCA subtypes and next-generation sequencing was performed. Survival modelling was carried out with patients >3 years old who received craniospinal irradiation (n=336). Association analysis confirmed relationships between methylation and WCA subtypes. Subtypes VI and VII were enriched for WCA-FR (p<0.0001) and aneuploidy, whereas subtype VIII was defined solely by i17q (p<0.0001). Whilst we observed an overall low mutational burden, WCA-HR harboured recurrent mutations in genes involved in chromatin remodelling (p=0.007). No gene-specific events were associated with disease risk, however integration of both methylation subtype and WCA groups enabled improved risk-stratification survival models that outperformed current schemes. The optimal MB_Grp4-specific model stratified patients into: favourable-risk (local disease, subtype VII or subtype VI with WCA-FR; 39/194 [20%], 97% 5-year PFS), very-high-risk (metastatic disease with WCA-HR; 71/194 [37%], 50% 5-year PFS) and high-risk (remaining patients; 84/194 [43%], 67% 5-year PFS). Findings were validated in independent cohorts. Comprehensive clinico-molecular assessment of MB_Grp4 provides important understanding of its clinical and biological heterogeneity. Our novel MB_Grp4 stratification scheme removes standard risk disease and identifies a favourable risk group (20% of MB_Grp4) with potential for therapy de-escalation. Current therapeutic strategies are insufficient for the very-high risk group (encompassing 37% of MB_Grp4), for whom novel therapies are urgently required.

PATH-06. Molecular subgrouping of medulloblastoma via low-depth whole genome bisulfite sequencing

INTRODUCTION: International consensus recognises four molecular subgroups of medulloblastoma, each with distinct molecular features and clinical outcomes. Assigning molecular subgroup is typically achieved via the Illumina DNA methylation microarray. Given the rapidly-expanding WGS capacity in healthcare institutions, there is an unmet need to develop platform-independent, sequence-based subgrouping assays. Whole genome bisulfite sequencing (WGBS) enables the assessment of genome-wide methylation status at single-base resolution. To date, its routine application for subgroup assignment has been limited, due to high economic cost and sample input requirements. Currently, no optimised pipeline exists that is tailored to handle samples sequenced at low-pass (i.e., <10x depth). METHODOLOGY: Two datasets were utilised; 36 newly sequenced low-depth (10x) and 42 publicly available high-depth (30x) WGBS medulloblastoma samples (n=34), alongside cerebellar control samples (n=8), all with matched DNA methylation microarray data. We applied imputation to low-pass WGBS data, assessed inter-platform correlation and identified molecular subgroups by directly integrating WGBS sample data with pre-existing array-trained models. We developed machine learning WGBS-based classifiers and compared performance against microarray. We optimised reference-free aneuploidy detection with low-pass WGBS and assessed concordance with microarray-derived aneuploidy calls. RESULTS: We optimised a pipeline for processing, QC, and analysis of low-pass WGBS data, suitable for routine molecular subgrouping and reference-free aneuploidy assessment that achieves 96% sensitivity compared to microarray approaches. A pilot study of the suitability of FFPE was promising, and we demonstrate that WGBS data can be integrated into existing array-trained models with high assignment probabilities. Also, WGBS-derived classifier performance measures exceeded microarray-derived classifiers. CONCLUSION: We describe a platform-independent WGBS assay for molecular subgrouping of medulloblastoma. It performs equivalently to array-based methods at increasingly comparable cost ($400 vs $580) and provides a proof-of-concept for routine clinical adoption using standard WGS technology. Finally, the full methylome enabled elucidation of additional biological heterogeneity that has hitherto been inaccessible.

MEDB-31. THE CLINICAL SIGNIFICANCE OF EXTENT OF RESECTION IN MEDULLOBLASTOMA

Medulloblastoma (MB) patients determined to have a sub-total resection (STR), defined by >1.5cm² post-surgical tumour residuum, receive intensified treatment regimes, but recently the designation of STR as a high risk feature is being questioned. We aimed to assess the clinical correlates of extent of resection (EOR) and its impact on survival, with particular consideration of EOR in relation to the four MB consensus molecular subgroups (WNT, SHH, Group 3, Group 4). We collected data from 1113 patients (n=419, UK CCLG institutions; n=694, published data) representing the largest ever combined cohort constructed to assess the impact of EOR in medulloblastoma. We performed association analyses and univariate/multivariate survival analysis using Kaplan-Meier, log-rank and Cox proportional hazard modelling, analysing overall survival (OS) cohort-wide and with reference to molecular subgroups and clinical features. Association analysis of the combined cohort evidenced that infant patients were more likely to have STR (p=0.02). In this whole-cohort analysis, EOR was significantly associated with survival in univariate analysis (HR 1.64, 95% CI 1.30-2.07, p=<0.001) but not in multivariate analysis. STR was variably prognostic in sub-cohort analyses of specific demographics and molecular subgroup; worse outcomes were observed in patients <5 years in SHH (p=0.044) and Group 4 (p=0.044). This was true for WNT patients >5 years old at diagnosis (p=0.034) although numbers were small and require validation in even larger cohorts. In this cohort of >1100 MBs, STR was significantly associated with a lower OS in univariate analysis, but this was driven by specific disease contexts (SHH and Group 4 patients <5 years old). STR was not independently prognostic overall or in any setting. We recommended that surgeons should continue to pursue maximal safe resection for all MB patients but suggest that consideration of STR as a high-risk feature should be disease context specific.

The Place and Value of Sodium-Glucose Cotransporter 2 Inhibitors in the Evolving Treatment Paradigm for Type 2 Diabetes Mellitus: A Narrative Review

Over recent years, the expanding evidence base for sodium-glucose cotransporter-2 inhibitor (SGLT2i) therapies has revealed benefits beyond their glucose-lowering efficacy in the treatment of Type 2 diabetes mellitus (T2DM), resulting in their recognition as cardiorenal medicines. While SGLT2is continue to be recommended among the second-line therapies for the treatment of hyperglycaemia, their true value now extends to the prevention of debilitating and costly cardiovascular and renal events for high-risk individuals, with particular benefit shown in reducing major adverse cardiac events and heart failure (HF) and slowing the progression of chronic kidney disease. However, SGLT2i usage is still suboptimal among groups considered to be at greatest risk of cardiorenal complications. The ongoing coronavirus disease 2019 (COVID-19) pandemic has intensified financial pressures on healthcare systems, which may hamper further investment in newer effective medicines. Emerging evidence indicates that glycaemic control should be prioritised for people with T2DM in the era of COVID-19 and practical advice on the use of T2DM medications during periods of acute illness remains important, particularly for healthcare professionals working in primary care who face multiple competing priorities. This article provides the latest update from the Improving Diabetes Steering Committee, including perspectives on the value of SGLT2is as cost-effective therapies within the T2DM treatment paradigm, with particular focus on the latest published evidence relating to the prevention or slowing of cardiorenal complications. The implications for ongoing and future approaches to diabetes care are considered in the light of the continuing coronavirus pandemic, and relevant aspects of international treatment guidelines are highlighted with practical advice on the appropriate use of SGLT2is in commonly occurring T2DM clinical scenarios. The 'SGLT2i Prescribing Tool for T2DM Management', previously published by the Steering Committee, has been updated to reflect the latest evidence and is provided in the Supplementary Materials to help support clinicians delivering T2DM care.

Meeting the Challenge of Virtual Diabetes Care: A Consensus Viewpoint on the Positioning and Value of Oral Semaglutide in Routine Clinical Practice

While glucagon-like peptide-1 receptor agonists (GLP-1 RAs), such as semaglutide, are among the most effective drugs for treating people with type 2 diabetes (T2D), they are clinically under-utilised. Until recently, the only route for semaglutide administration was via subcutaneous injection. However, an oral formulation of semaglutide was recently licensed, with the potential to address therapy inertia and increase patient adherence to treatment, which is essential in controlling blood glucose and reducing complications. The availability of oral semaglutide provides a new option for both clinicians and patients who are reluctant to use an injectable agent. This has been of particular importance in addressing the challenge of virtual diabetes care during the COVID-19 pandemic, circumventing the logistical problems that are often associated with subcutaneous medication administration. However, there remains limited awareness of the clinical and economic value of oral semaglutide in routine clinical practice. In this article, we present our consensus opinion on the role of oral semaglutide in routine clinical practice and discuss its value in reducing the burden of delivering diabetes care in the post-COVID-19 pandemic period of chronic disease management.

Single-cell DNA sequencing identifies risk-associated clonal complexity and evolutionary trajectories in childhood medulloblastoma development

We reconstructed the natural history and temporal evolution of the most common childhood brain malignancy, medulloblastoma, by single-cell whole-genome sequencing (sc-WGS) of tumours representing its major molecular sub-classes and clinical risk groups. Favourable-risk disease sub-types assessed (MB_WNT and infant desmoplastic/nodular MB_SHH) typically comprised a single clone with no evidence of further evolution. In contrast, highest risk sub-classes (MYC-amplified MB_Group3 and TP53-mutated MB_SHH) were most clonally diverse and displayed gradual evolutionary trajectories. Clinically adopted biomarkers (e.g. chromosome 6/17 aberrations; CTNNB1/TP53 mutations) were typically early-clonal/initiating events, exploitable as targets for early-disease detection; in analyses of spatially distinct tumour regions, a single biopsy was sufficient to assess their status. Importantly, sc-WGS revealed novel events which arise later and/or sub-clonally and more commonly display spatial diversity; their clinical significance and role in disease evolution post-diagnosis now require establishment. These findings reveal diverse modes of tumour initiation and evolution in the major medulloblastoma sub-classes, with pathogenic relevance and clinical potential.

Emergence and maintenance of actionable genetic drivers at medulloblastoma relapse

Background

Less than 5% of medulloblastoma (MB) patients survive following failure of contemporary radiation-based therapies. Understanding the molecular drivers of medulloblastoma relapse (rMB) will be essential to improve outcomes. Initial genome-wide investigations have suggested significant genetic divergence of the relapsed disease.

Methods

We undertook large-scale integrated characterization of the molecular features of rMB—molecular subgroup, novel subtypes, copy number variation (CNV), and driver gene mutation. 119 rMBs were assessed in comparison with their paired diagnostic samples (n = 107), alongside an independent reference cohort sampled at diagnosis (n = 282). rMB events were investigated for association with outcome post-relapse in clinically annotated patients (n = 54).

Results

Significant genetic evolution occurred over disease-course; 40% of putative rMB drivers emerged at relapse and differed significantly between molecular subgroups. Non-infant MBSHH displayed significantly more chromosomal CNVs at relapse (TP53 mutation-associated). Relapsed MB_Group4 demonstrated the greatest genetic divergence, enriched for targetable (eg, CDK amplifications) and novel (eg, USH2A mutations) events. Importantly, many hallmark features of MB were stable over time; novel subtypes (>90% of tumors) and established genetic drivers (eg, SHH/WNT/P53 mutations; 60% of rMB events) were maintained from diagnosis. Critically, acquired and maintained rMB events converged on targetable pathways which were significantly enriched at relapse (eg, DNA damage signaling) and specific events (eg, 3p loss) predicted survival post-relapse.

Conclusions

rMB is characterised by the emergence of novel events and pathways, in concert with selective maintenance of established genetic drivers. Together, these define the actionable genetic landscape of rMB and provide a basis for improved clinical management and development of stratified therapeutics, across disease-course.

OMIC-06. MOLECULAR SUBGROUPING OF MEDULLOBLASTOMA VIA LOW-DEPTH WHOLE GENOME BISULFITE SEQUENCING

Introduction

International consensus recognises four molecular subgroups of medulloblastoma, each with distinct molecular features and clinical outcomes. The current gold-standard for subgroup assignment is DNA methylation microarray. There is an unmet need to develop platform-independent subgrouping assays which are both non-proprietary and compatible with rapidly-expanding WGS capacity in healthcare. Whole Genome Bisulfite Sequencing (WGBS) enables the assessment of genome-wide methylation status at single-base resolution. Previously, WGBS adoption has been limited by cost and sample quality/quantity requirements. Its application for routine detection of medulloblastoma subgroups has not previously been reported.

Methodology

Two datasets were utilised; 36 newly-sequenced low-depth (10x coverage) and 34 publicly-available high-depth (30x) WGBS medulloblastomas, all with matched DNA methylation microarray data. We compared platform concordance and identified molecular subgroups. Machine-learning WGBS-based subgroup classifiers were optimised and compared between platforms. Aneuploidy and mutation detection using WGBS was optimised and compared to microarray-derived estimates where possible. Finally, comprehensive subgroup-specific DNA methylation signatures were identified.

Results

We optimised a pipeline for processing, quality control and analysis of low-depth WGBS data, suitable for routine molecular subgrouping and aneuploidy assessment. We demonstrated the suitability of fresh-frozen and FFPE DNA for WGBS, and, using downsampling, showed that subgroup calling is robust at coverages as low as 2x. We identified differentially methylated regions that, due to poor representation, could not be detected using methylation microarrays. Molecular subgroups of medulloblastoma assigned using WGBS were concordant with array-based definitions, and WGBS-derived classifier performance measures exceeded microarray-derived classifiers.

Conclusion

We describe a platform-independent assay for molecular subgrouping of medulloblastoma using WGBS. It performs equivalently to current array-based methods at comparable cost ($405 vs $596) and provides a proof-of-concept for its routine clinical adoption using standard WGS technology. Finally, the full methylome enabled elucidation of additional biological heterogeneity that has hitherto been inaccessible.

EMBR-25. GENOME-WIDE GENETIC AND EPIGENETIC ASSESSMENT OF GROUP 4 MEDULLOBLASTOMA FOR IMPROVED, BIOMARKER DRIVEN, PROGNOSTICATION AND RISK-STRATIFICATION

Introduction

Medulloblastoma (MB) is the most common malignant brain tumour in children. The most frequent molecular subgroup, Group 4 (MBGrp4) accounts for ~35/40% of cases, however it has the least understood underlying biology. Clinical outcomes are heterogeneous in MBGrp4 and are not accounted for by established clinico-pathological risk factors. There is now a requirement for a comprehensive study of MBGrp4, considering established clinico-pathological features and novel molecular biomarkers to enhance risk-stratification and identify novel therapeutic targets.

Methods

A clinically-annotated, retrospective MBGrp4 discovery cohort (n = 420) was generated from UK CCLG institutions, collaborating European centres and SIOP-UKCCSG-PNET3 and HIT-SIOP-PNET4 clinical trials. Contemporary, multi-omics profiling was performed. Focal and arm level copy number aberrations (CNAs) were determined from molecular inversion probe (MIP) or DNA methylation array which additionally provided next generation non-WNT/non-SHH (Grp3/Grp4) subtype classifications. Targeted next-generation DNA sequencing was performed to overlay the mutational landscape. Survival modelling was carried out with patients &gt;3 years old who received craniospinal irradiation.

Results

MBGrp4 subtypes were assigned to 88% of tumours with available data. Subtype VIII was strongly associated with i17q (p&lt;0.0001). The favourable-risk cytogenetic signature (2 or 3 of; chromosome 7 gain, chromosome 8 loss and/or chromosome 11 loss) associated with both subtypes VI and VII (p&lt;0.0001). MYCN amplifications were strongly associated with subtype V (p&lt;0.0001) in addition to 16q loss (p&lt;0.0001). The high-risk CNA group was enriched for mutations in genes involved in chromatin remodelling (p&lt;0.0001). Risk factors were identified from multivariate survival modelling. Subtype and CNA groups contributed to improved risk-stratification models that outperformed current clinical schemes.

Conclusion

Comprehensive genetic and epigenetic profiling in this large retrospective cohort has improved our understanding of the molecular and clinical heterogeneity within MBGrp4. Incorporation of molecular biomarkers improved risk-stratification for MBGrp4.

Advanced molecular pathology for rare tumours: A national feasibility study and model for centralised medulloblastoma diagnostics

Aims

Application of advanced molecular pathology in rare tumours is hindered by low sample numbers, access to specialised expertise/technologies and tissue/assay QC and rapid reporting requirements. We assessed the feasibility of co‐ordinated real‐time centralised pathology review (CPR), encompassing molecular diagnostics and contemporary genomics (RNA‐seq/DNA methylation‐array).

Methods

This nationwide trial in medulloblastoma (<80 UK diagnoses/year) introduced a national reference centre (NRC) and assessed its performance and reporting to World Health Organisation standards. Paired frozen/formalin‐fixed, paraffin‐embedded tumour material were co‐submitted from 135 patients (16 referral centres).

Results

Complete CPR diagnostics were successful for 88% (120/135). Inadequate sampling was the most common cause of failure; biomaterials were typically suitable for methylation‐array (129/135, 94%), but frozen tissues commonly fell below RNA‐seq QC requirements (53/135, 39%). Late reporting was most often due to delayed submission. CPR assigned or altered histological variant (vs local diagnosis) for 40/135 tumours (30%). Benchmarking/QC of specific biomarker assays impacted test results; fluorescent in‐situ hybridisation most accurately identified high‐risk MYC/MYCN amplification (20/135, 15%), while combined methods (CTNNB1/chr6 status, methylation‐array subgrouping) best defined favourable‐risk WNT tumours (14/135; 10%). Engagement of a specialist pathologist panel was essential for consensus assessment of histological variants and immunohistochemistry. Overall, CPR altered clinical risk‐status for 29% of patients.

Conclusion

National real‐time CPR is feasible, delivering robust diagnostics to WHO criteria and assignment of clinical risk‐status, significantly altering clinical management. Recommendations and experience from our study are applicable to advanced molecular diagnostics systems, both local and centralised, across rare tumour types, enabling their application in biomarker‐driven routine diagnostics and clinical/research studies.

3D Echocardiography Provides Highly Accurate 3D Printed Models in Congenital Heart Disease

Cardiac 3D printing is mainly performed from magnetic resonance imaging (MRI) and computed tomography (CT) 3D datasets, though anatomic detail of atrioventricular (AV) valves may be limited. 3D echo provides excellent visualization of AV valves. Thus, we tested the feasibility and accuracy of 3D printing from 3D echo in this pilot series of subjects with congenital heart disease (CHD), with a focus on valve anatomy. Five subjects with CHD were identified. 3D echo data were converted to 3D printable files and printed in collaboration with 3D Systems Healthcare (Golden, Colorado). A novel technique for valve modeling was utilized using commercially available software. Two readers (KM, SA) independently measured valve structures from 3D models and compared to source echo images. 3D printing was feasible for all cases. Table 1 shows measurements comparing 2D echo to 3D models. Bland Altman analysis showed close agreement and no significant bias between 2D and digital 3D models (mean difference 0.0, 95% CI 1.1 to - 1.1) or 2D vs printed 3D models, though with wider limits of agreement (mean difference - 0.3, 95% CI 1.9 to - 2.6). Accuracy of 3D models compared to 2D was within < 0.5 mm. This pilot study shows 3D echo datasets can be used to reliably print AV and semilunar valve structures in CHD. The 3D models are highly accurate compared to the source echo images. This is a novel and value-added technique that adds incremental information on cardiac anatomy over current methods.

Risk Prediction of the Diabetes Missing Million: Identifying Individuals at High Risk of Diabetes and Related Complications

Early diagnosis and effective management of type 2 diabetes (T2D) are crucial in reducing the risk of developing life-changing complications such as heart failure, stroke, kidney disease, blindness and amputation, which are also associated with significant costs for healthcare providers. However, as T2D symptoms often develop slowly it is not uncommon for people to live with T2D for years without being aware of their condition-commonly known as the undiagnosed missing million. By the time a diagnosis is received, many individuals will have already developed serious complications. While the existence of undiagnosed diabetes has long been recognised, wide-reaching awareness among the general public, clinicians and policymakers is lacking, and there is uncertainty in how best to identify high-risk individuals. In this article we have used consensus expert opinion alongside the available evidence, to provide support for the diabetes healthcare community regarding risk prediction of the missing million. Its purpose is to provide awareness of the risk factors for identifying individuals at high, moderate and low risk of T2D and T2D-related complications. The awareness of risk predictors, particularly in primary care, is important, so that appropriate steps can be taken to reduce the clinical and economic burden of T2D and its complications.

MBRS-44. TIME, PATTERN AND OUTCOME OF MEDULLOBLASTOMA RELAPSE ARE ASSOCIATED WITH TUMOUR BIOLOGY AT DIAGNOSIS AND UPFRONT THERAPY: A COHORT STUDY

Disease relapse occurs in ~30% of children with medulloblastoma, and is fatal in the majority. We sought to establish whether clinico-molecular characteristics at diagnosis are associated with the nature of relapse, subsequent disease-course, and whether these associations could inform clinical management. We surveyed the clinical features of medulloblastoma relapse (time-to-relapse, pattern-of-relapse, time-to-death and overall outcome) in 247 centrally-reviewed patients who relapsed following standard-upfront-therapies. We related these to clinico-molecular features at diagnosis, prognostic factors, and first-line/relapse treatment. Patients who received upfront craniospinal irradiation (CSI-treated) displayed prolonged time-to-relapse compared to CSI naïve patients (p<0.001). Similarly, in CSI naïve patients, CSI at relapse, alongside re-resection and desmoplastic/nodular histology, were associated with long-term survival. In CSI-treated patients, the nature of relapse was subgroup-dependent. Local-nodular relapse patterns were enriched in relapsed-MB_SHH patients (p<0.001), but a notable proportion (65%) also acquired distant-diffuse disease (p=0.010). MB_Group3 relapsed quickly (median 1.3 years), MB_Group4 slowly (median 2.1 years). Distant-disease was prevalent in MB_Group3 and MB_Group4 relapses (90%) but, in contrast to relapsed-MB_SHH, nodular and diffuse patterns of distant-disease were observed. Furthermore, nodular disease was associated with a prolonged time-to-death post-relapse (p=0.006). Investigation of second-generation MB_Group3/4 subtypes refined our understanding of heterogeneous relapse characteristics. Subtype VIII had prolonged time-to-relapse; subtype II a rapid time-to-death. Subtypes II/III/VIII developed a significantly higher incidence of distant-disease at relapse, whereas subtypes V/VII did not. The nature of medulloblastoma relapse are biology and therapy-dependent, providing immediate translational opportunities for improved disease management through biology-directed surveillance, post-relapse prognostication and risk-stratified selection of second-line treatment.

MBRS-69. METABOLITE PROFILING OF SHH MEDULLOBLASTOMA IDENTIFIES A SUBSET OF CHILDHOOD TUMOURS ENRICHED FOR HIGH-RISK MOLECULAR BIOMARKERS AND CLINICAL FEATURES

SHH medulloblastoma patients have a variable prognosis. Infants (&lt;3–5 years at diagnosis) are associated with a good prognosis, while disease-course in childhood is associated with specific prognostic biomarkers (MYCN amplification, TP53 mutation, LCA histology; all high-risk). There is an unmet need to identify prognostic subgroups of SHH tumours rapidly in the clinical setting, to aid in real-time risk stratification and disease management. Metabolite profiling is a powerful technique for characterising tumours. High resolution magic angle spinning NMR spectroscopy (HR-MAS) can be performed on frozen tissue samples and provides high quality metabolite information. We therefore assessed whether metabolite profiles could identify subsets of SHH tumours with prognostic potential. Metabolite concentrations of 22 SHH tumours were acquired by HR-MAS and analysed using unsupervised hierarchical clustering. Methylation profiling assigned the infant and childhood SHH subtypes, and clinical and molecular features were compared between clusters. Two clusters were observed. A significantly higher concentration of lipids was observed in Cluster 1 (t-test, p=0.012). Cluster 1 consisted entirely of childhood-SHH whilst Cluster 2 included both childhood-SHH and infant-SHH subtypes. Cluster 1 was enriched for high-risk markers - LCA histology (3/7 v. 0/5), MYCN amplification (2/7 v. 0/5), TP53 mutations (3/7 v. 1/5) and metastatic disease - whilst having a lower proportion of TERT mutations (0/7 v. 2/5) than Cluster 2. These pilot results suggest that (i) it is possible to identify childhood-SHH patients linked to high-risk clinical and molecular biomarkers using metabolite profiles and (ii) these may be detected non-invasively in vivo using magnetic-resonance spectroscopy.

QOL-17. BIOLOGICAL CORRELATES OF QUALITY OF SURVIVAL AND NEUROCOGNITIVE OUTCOMES IN MEDULLOBLASTOMA; A META-ANALYSIS OF THE SIOP-UKCCSG-PNET3 AND HIT-SIOP-PNET4 TRIALS

Relationships between biological factors (genetic, tumour molecular subgroup) and neurocognitive/Quality of Survival (QoS) outcomes in medulloblastoma survivors are emerging, based on studies of limited retrospective cohorts. Integrated investigations of the medulloblastoma late-effects pathway (considering biological, clinical and treatment factors), using larger clinically-controlled cohorts, are now essential to determine their independent significance and potential for clinical application. In a combined cohort of SIOP-UKCCSG-PNET3 and HIT-SIOP-PNET4 patients (n=150), molecular subgroup (MB_WNT, MB_SHH, MB_Grp3, MB_Grp4) was assessed against QoS measures [health status: HUI3; emotional and behavioural difficulties: SDQ; Health-related Quality of Life (HrQoL): PedsQL]. Additionally, in DNA remaining from HIT-SIOP-PNET4 (n=74), 39 candidate SNPs (involved in metabolism, DNA maintenance/repair, neural growth/repair and oxidative stress/inflammation) were genotyped by multiplexed MALDI-TOF MassArray and assessed against Wechsler Intelligence Scale (WISC) scores. Molecular subgroup was significantly associated with HrQoL and health status in univariate analyses; MB_Grp4 predicted significantly worse outcomes than MB_SHH and MB_Grp3 (p<0.05), but not in multivariate analyses taking into consideration other significant and reported QoS predictors (e.g. treatment, gender, age). In contrast, 6 SNPs were significantly associated with ≥1 WISC domain; 4/6 showed associations across domains. 3 SNPs were independently prognostic in multivariate analyses, and further significant associations were apparent at the gene (BDNF, APOE) and pathway (folate) level. This cross-discipline, international study encompassing two medulloblastoma trials has identified relationships between molecular subgroup, genotype and survivorship outcomes. These findings now require assessment in larger series, to inform our understanding of medulloblastoma survivorship outcomes and impact future disease management strategies.

SGLT2 Inhibitors: Slowing of Chronic Kidney Disease Progression in Type 2 Diabetes

Diabetic kidney disease (DKD) is a topic of increasing concern among clinicians involved in the management of type 2 diabetes mellitus (T2DM). It is a progressive and costly complication associated with increased risk of adverse cardiovascular (CV) and renal outcomes and mortality. Ongoing monitoring of the estimated glomerular filtration (eGFR) rate alongside the urine albumin:creatinine ratio (ACR) is recommended during regular T2DM reviews to enable a prompt DKD diagnosis or to assess disease progression, providing an understanding of adverse risk for each individual. Many people with DKD will progress to end-stage kidney disease (ESKD), requiring renal replacement therapy (RRT), typically haemodialysis or kidney transplantation. A range of lifestyle and pharmacological interventions is recommended to help lower CV risk, slow the advancement of DKD and prevent or delay the need for RRT. Emerging evidence concerning sodium-glucose co-transporter-2 inhibitor (SGLT2i) agents suggests a role for these medicines in slowing eGFR decline, enabling regression of albuminuria and reducing progression to ESKD. Improvements in renal end points observed in SGLT2i CV outcome trials (CVOTs) highlighted the possible impact of these agents in the management of DKD. Data from the canagliflozin CREDENCE trial (Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation) have since demonstrated the effectiveness of this medicine in reducing the risk of kidney failure and CV events in a population comprising individuals with T2DM and renal disease. CREDENCE was the first SGLT2i study to examine renal outcomes as the primary end point. Real-world studies have reaffirmed these outcomes in routine clinical practice. This article summarises the evidence regarding the use of SGLT2i medicines in slowing the progression of DKD and examines the possible mechanisms underpinning the renoprotective effects of these agents. The relevant national and international guidance for monitoring and treatment of DKD is also highlighted to help clinicians working to support this vulnerable group.

Time, pattern, and outcome of medulloblastoma relapse and their association with tumour biology at diagnosis and therapy: a multicentre cohort study

Background

Disease relapse occurs in around 30% of children with medulloblastoma, and is almost universally fatal. We aimed to establish whether the clinical and molecular characteristics of the disease at diagnosis are associated with the nature of relapse and subsequent disease course, and whether these associations could inform clinical management.

Methods

In this multicentre cohort study we comprehensively surveyed the clinical features of medulloblastoma relapse (time to relapse, pattern of relapse, time from relapse to death, and overall outcome) in centrally reviewed patients who relapsed following standard upfront therapies, from 16 UK Children's Cancer and Leukaemia Group institutions and four collaborating centres. We compared these relapse-associated features with clinical and molecular features at diagnosis, including established and recently described molecular features, prognostic factors, and treatment at diagnosis and relapse.

Findings

247 patients (175 [71%] boys and 72 [29%] girls) with medulloblastoma relapse (median year of diagnosis 2000 [IQR 1995–2006]) were included in this study. 17 patients were later excluded from further analyses because they did not meet the age and treatment criteria for inclusion. Patients who received upfront craniospinal irradiation (irradiated group; 178 [72%] patients) had a more prolonged time to relapse compared with patients who did not receive upfront craniospinal irradiation (non-irradiated group; 52 [21%] patients; p<0·0001). In the non-irradiated group, craniospinal irradiation at relapse (hazard ratio [HR] 0·27, 95% CI 0·11–0·68) and desmoplastic/nodular histology (0·23, 0·07–0·77) were associated with prolonged time to death after relapse, MYC amplification was associated with a reduced overall survival (23·52, 4·85–114·05), and re-resection at relapse was associated with longer overall survival (0·17, 0·05–0·57). In the irradiated group, patients with MB_Group3 tumours relapsed significantly more quickly than did patients with MB_Group4 tumours (median 1·34 [0·99–1·89] years vs 2·04 [1·39–3·42 years; p=0·0043). Distant disease was prevalent in patients with MB_Group3 (23 [92%] of 25 patients) and MB_Group4 (56 [90%] of 62 patients) tumour relapses. Patients with distantly-relapsed MB_Group3 and MB_Group4 displayed both nodular and diffuse patterns of disease whereas isolated nodular relapses were rare in distantly-relapsed MB_SHH (1 [8%] of 12 distantly-relapsed MB_SHH were nodular alone compared with 26 [34%] of 77 distantly-relapsed MB_Group3 and MB_Group4). In MB_Group3 and MB_Group4, nodular disease was associated with a prolonged survival after relapse (HR 0·42, 0·21–0·81). Investigation of second-generation MB_Group3 and MB_Group4 molecular subtypes refined our understanding of heterogeneous relapse characteristics. Subtype VIII had prolonged time to relapse and subtype II had a rapid time from relapse to death. Subtypes II, III, and VIII developed a significantly higher incidence of distant disease at relapse whereas subtypes V and VII did not (equivalent rates to diagnosis).

Interpretation

This study suggests that the nature and outcome of medulloblastoma relapse are biology and therapy-dependent, providing translational opportunities for improved disease management through biology-directed disease surveillance, post-relapse prognostication, and risk-stratified selection of second-line treatment strategies.

Funding

Cancer Research UK, Action Medical Research, The Tom Grahame Trust, The JGW Patterson Foundation, Star for Harris, The Institute of Child Health - Newcastle University - Institute of Child Health High-Risk Childhood Brain Tumour Network (co-funded by The Brain Tumour Charity, Great Ormond Street Children's Charity, and Children with Cancer UK).

The molecular landscape and associated clinical experience in infant medulloblastoma: prognostic significance of second-generation subtypes

AIMS

Biomarker-driven therapies have not been developed for infant medulloblastoma (iMB). We sought to robustly sub-classify iMB, and proffer strategies for personalized, risk-adapted therapies.

METHODS

We characterized the iMB molecular landscape, including second-generation subtyping, and the associated retrospective clinical experience, using large independent discovery/validation cohorts (n = 387).

RESULTS

iMB_Grp3 (42%) and iMB_SHH (40%) subgroups predominated. iMB_Grp3 harboured second-generation subtypes II/III/IV. Subtype II strongly associated with large-cell/anaplastic pathology (LCA; 23%) and MYC amplification (19%), defining a very-high-risk group (0% 10yr overall survival (OS)), which progressed rapidly on all therapies; novel approaches are urgently required. Subtype VII (predominant within iMB_Grp4 ) and subtype IV tumours were standard risk (80% OS) using upfront CSI-based therapies; randomized-controlled trials of upfront radiation-sparing and/or second-line radiotherapy should be considered. Seventy-five per cent of iMB_SHH showed DN/MBEN histopathology in discovery and validation cohorts (P < 0.0001); central pathology review determined diagnosis of histological variants to WHO standards. In multivariable models, non-DN/MBEN pathology was associated significantly with worse outcomes within iMB_SHH . iMB_SHH harboured two distinct subtypes (iMB_SHH-I/II ). Within the discriminated favourable-risk iMB_SHH DN/MBEN patient group, iMB_SHH-II had significantly better progression-free survival than iMB_SHH-I , offering opportunities for risk-adapted stratification of upfront therapies. Both iMB_SHH-I and iMB_SHH-II showed notable rescue rates (56% combined post-relapse survival), further supporting delay of irradiation. Survival models and risk factors described were reproducible in independent cohorts, strongly supporting their further investigation and development.

CONCLUSIONS

Investigations of large, retrospective cohorts have enabled the comprehensive and robust characterization of molecular heterogeneity within iMB. Novel subtypes are clinically significant and subgroup-dependent survival models highlight opportunities for biomarker-directed therapies.

Abstract B73: Second-generation molecular subgrouping of medulloblastoma: An international meta-analysis of Group 3 and Group 4 subtypes

In 2012, an international consensus paper reported that medulloblastoma comprises four molecular subgroups (WNT, SHH, Group 3, Group 4), each associated with distinct genomic features and clinical behavior. Independently, multiple recent reports have defined further intra-subgroup heterogeneity in the form of biologically and clinically relevant subtypes. However, owing to differences in patient cohorts and analytical methods, estimates of subtype number and definition have been inconsistent, especially within Group 3 and Group 4. Herein, we aimed to reconcile the definition of Group 3/Group 4 MB subtypes through the analysis of a series of 1,501 medulloblastomas with DNA methylation profiling data, including 852 with matched transcriptome data. Using multiple complementary bioinformatic approaches, we compared the concordance of subtype calls between published cohorts and analytical methods, including assessments of class definition confidence and reproducibility. While lowest-complexity solutions continued to support the original consensus subgroups of Group 3 and Group 4, our analysis most strongly supported a definition comprising eight robust Group 3/Group 4 subtypes (Types I-VIII). Subtype II was consistently identified across all component studies, while all others were supported by multiple class-definition methods. Regardless of analytical technique, increasing cohort size did not further increase the number of identified Group 3/Group 4 subtypes. Summarizing the molecular and clinicopathologic features of these eight subtypes indicated enrichment of specific driver gene alterations and cytogenetic events among subtypes and identified highly disparate survival outcomes, further supporting their biologic and clinical relevance. Collectively, this study provides continued support for consensus groups 3 and 4, while enabling robust derivation of, and categorical accounting for, the extensive intertumoral heterogeneity within Groups 3 and 4, revealed by recent high-resolution subclassification approaches. Further, these findings provide a basis for application of emerging methods (e.g., proteomics/single-cell approaches) that may additionally inform medulloblastoma subclassification. Outputs from this study will help shape definition of the next generation of medulloblastoma clinical protocols and facilitate the application of enhanced molecularly guided risk stratification to improve outcomes and quality of life for patients and their families.

Citation Format: Tanvi Sharma, Edward C. Schwalbe, Daniel W. Williamson, Martin Sill, Volker Hovestadt, Martin Mynarek, Stefan Rutkowski, Giles W. Robinson, Amar Gajjar, Florence Cavalli, Vijay Ramaswamy, Michael D. Taylor, Janet C. Lindsey, Rebecca M. Hill, Natalie Jäger, Andrey Korshunov, Debbie Hicks, Simon Bailey, Marcel Kool, Lukas Chavez, Paul A. Northcott, Stefan M. Pfister, Steven C. Clifford. Second-generation molecular subgrouping of medulloblastoma: An international meta-analysis of Group 3 and Group 4 subtypes [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr B73.

Correction to: Optimising the Benefits of SGLT2 Inhibitors for Type 1 Diabetes

In the original article, Associated Medical Education Section has been published mistakenly. It has been removed from the original publication.

Effects of the growth pattern of medulloblastoma on short-term neurological impairments after surgery: results from the prospective multicenter HIT-SIOP PNET 4 study

OBJECTIVE

Extensive resection of a tumor in the posterior fossa in children is associated with the risk of neurological deficits. The objective of this study was to prospectively evaluate the short-term neurological morbidity in children after medulloblastoma surgery and relate this to the tumor's growth pattern and to the extent of resection.

METHODS

In 160 patients taking part in the HIT-SIOP PNET 4 (Hyperfractionated Versus Conventionally Fractionated Radiotherapy in Standard Risk Medulloblastoma) trial, neurosurgeons prospectively responded to questions concerning the growth pattern of the tumor they had resected. The extent of resection (gross, near, or subtotal) was evaluated using MRI. The patients' neurological status before resection and around 30 days after resection was recorded.

RESULTS

Invasive tumor growth, defined as local invasion in the brain or meninges, cranial nerve, or major vessel, was reported in 58% of the patients. After surgery almost 70% of all patients were affected by one or several neurological impairments (e.g., impaired vision, impaired extraocular movements, and ataxia). However, this figure was very similar to the preoperative findings. Invasive tumor growth implied a significantly higher number of impairments after surgery (p = 0.03) and greater deterioration regarding extraocular movements (p = 0.012), facial weakness (p = 0.048), and ataxia in the arms (p = 0.014) and trunk (p = 0.025) compared with noninvasive tumor growth. This deterioration was not dependent on the extent of resection performed. Progression-free survival (PFS) at 5 years was 80% ± 4% and 76% ± 5% for patients with invasive and noninvasive tumor growth, respectively, with no difference in the 5-year PFS for extent of resection.

CONCLUSIONS

Preoperative neurological impairments and invasive tumor growth were strong predictors of deterioration in short-term neurological outcome after medulloblastoma neurosurgery, whereas the extent of resection was not. Neither tumor invasiveness nor extent of resection influenced PFS. These findings support the continuation of maximal safe resection in medulloblastoma surgery where functional risks are not taken in areas with tumor invasion.

Optimising the Benefits of SGLT2 Inhibitors for Type 1 Diabetes

Sodium-glucose cotransporter 2 (SGLT2) inhibitor clinical studies in type 1 diabetes mellitus (T1DM) have demonstrated reduced HbA1c and lower glucose variability with increased time in optimal glucose range as well as additional benefits of reductions in weight and insulin dose without increasing the incidence of hypoglycaemia. However, the appropriate use of SGLT2 inhibitor therapies within clinical practise to treat people with T1DM remains unclear. In this article we have used consensus expert opinion alongside the available evidence, product indication and most recent clinical guidance to provide support for the diabetes healthcare community regarding the appropriate use of SGLT2 inhibitors, focussing on specific considerations for appropriate prescribing of dapagliflozin within the T1DM management pathway. Its purpose is to provide awareness of the issues surrounding treatment with dapagliflozin in T1DM as well as offer practical guidance that also includes a checklist tool for appropriate dapagliflozin prescribing. The checklist aims to support clinicians in identifying those people with T1DM most likely to benefit from dapagliflozin treatment as well as situations where caution may be required.Funding: AstraZeneca UK Ltd.

Imaging Characteristics of Wingless Pathway Subgroup Medulloblastomas: Results from the German HIT/SIOP-Trial Cohort

BACKGROUND AND PURPOSE

In addition to the 4 histopathologically defined entities of medulloblastoma, 4 distinct genetically defined subgroups have been included in the World Health Organization classification of 2016. The smallest subgroup is the medulloblastoma with activated wingless pathway. The goal of this study was to identify a typical MR imaging morphology in a larger number of pediatric patients with wingless pathway medulloblastoma.

MATERIALS AND METHODS

From January 2001 to October 2017, of 75 patients with histologically confirmed and molecularly subgrouped wingless pathway medulloblastomas recruited to the German Pediatric Brain Tumor (HIT) trials, 38 patients (median age, 12.8 ± 4.6 years at diagnosis; 24 [63.2%] female) had preoperative imaging that passed the entry criteria for this study. Images were rated by the local standardized imaging criteria of the National Reference Center of Neuroradiology. Additionally, a modified laterality score was used to determine tumor localization and extension.

RESULTS

Twenty-eight of 38 (73.7%) were primary midline tumors but with a lateral tendency in 39.3%. One extensively eccentric midline tumor was rated by the laterality score as in an off-midline position. Five tumors were found in the cerebellopontine angle; 3, in the deep white matter; and 2, in a cerebellar hemisphere. Leptomeningeal dissemination was rare (11.5%). In 60.5%, intratumoral blood-degradation products were found, and 26.3% showed cysts with blood contents.

CONCLUSIONS

According to our observations, wingless pathway medulloblastomas are not preferentially off-midline tumors as postulated in previous studies with smaller wingless pathway medulloblastoma cohorts. Dense intratumoral blood-degradation products and cysts with blood contents are frequently found and might help to differentiate wingless pathway medulloblastoma from other medulloblastoma subtypes.

Correction to: SGLT2 Inhibitors: Cardiovascular Benefits Beyond HbA1c-Translating Evidence into Practice

In the original publication, Table 2 note was incorrectly published as "SGLT2i therapies may be initiated in people with eGFR 60 mL/min/1.73 m². Individuals already treated with canagliflozin or empagliflozin who demonstrate renal decline may continue treatment until eGFR reaches < 45 mL/min/1.73 m²".

SGLT2 Inhibitors: Cardiovascular Benefits Beyond HbA1c-Translating Evidence into Practice

Cardiovascular disease (CVD), including heart failure (HF), is a leading cause of morbidity and mortality in people with type 2 diabetes mellitus (T2DM). CVD and T2DM share common risk factors for development and progression, and there is significant overlap between the conditions in terms of worsening outcomes. In assessing the cardiovascular (CV) safety profiles of anti-diabetic drugs, sodium-glucose co-transporter-2 inhibitor (SGLT2i) therapies have emerged with robust evidence for reducing the risk of adverse CVD outcomes in people with T2DM who have either established CVD or are at risk of developing CVD. A previous consensus document from the Improving Diabetes Steering Committee has examined the potential role of SGLT2is in T2DM management and considered the risk-benefit profile of the class and the appropriate place for these medicines within the T2DM pathway. This paper builds on these findings and presents practical guidance for maximising the pleiotropic benefits of this class of medicines in people with T2DM in terms of reducing adverse CVD outcomes. The Improving Diabetes Steering Committee aims to offer evidence-based practical guidance for the use of SGLT2i therapies in people with T2DM stratified by CVD risk. This is of particular importance currently because some treatment guidelines have not been updated to reflect recent evidence from cardiovascular outcomes trials (CVOTs) and real-world studies that complement the CVOTs. The Improving Diabetes Steering Committee seeks to support healthcare professionals (HCPs) in appropriate treatment selection for people with T2DM who are at risk of developing or have established CVD and examines the role of SGLT2i therapy for these people.Funding: Napp Pharmaceuticals Limited.

Second-generation molecular subgrouping of medulloblastoma: an international meta-analysis of Group 3 and Group 4 subtypes

In 2012, an international consensus paper reported that medulloblastoma comprises four molecular subgroups (WNT, SHH, Group 3, and Group 4), each associated with distinct genomic features and clinical behavior. Independently, multiple recent reports have defined further intra-subgroup heterogeneity in the form of biologically and clinically relevant subtypes. However, owing to differences in patient cohorts and analytical methods, estimates of subtype number and definition have been inconsistent, especially within Group 3 and Group 4. Herein, we aimed to reconcile the definition of Group 3/Group 4 MB subtypes through the analysis of a series of 1501 medulloblastomas with DNA-methylation profiling data, including 852 with matched transcriptome data. Using multiple complementary bioinformatic approaches, we compared the concordance of subtype calls between published cohorts and analytical methods, including assessments of class-definition confidence and reproducibility. While the lowest complexity solutions continued to support the original consensus subgroups of Group 3 and Group 4, our analysis most strongly supported a definition comprising eight robust Group 3/Group 4 subtypes (types I–VIII). Subtype II was consistently identified across all component studies, while all others were supported by multiple class-definition methods. Regardless of analytical technique, increasing cohort size did not further increase the number of identified Group 3/Group 4 subtypes. Summarizing the molecular and clinico-pathological features of these eight subtypes indicated enrichment of specific driver gene alterations and cytogenetic events amongst subtypes, and identified highly disparate survival outcomes, further supporting their biological and clinical relevance. Collectively, this study provides continued support for consensus Groups 3 and 4 while enabling robust derivation of, and categorical accounting for, the extensive intertumoral heterogeneity within Groups 3 and 4, revealed by recent high-resolution subclassification approaches. Furthermore, these findings provide a basis for application of emerging methods (e.g., proteomics/single-cell approaches) which may additionally inform medulloblastoma subclassification. Outputs from this study will help shape definition of the next generation of medulloblastoma clinical protocols and facilitate the application of enhanced molecularly guided risk stratification to improve outcomes and quality of life for patients and their families.

Abstract P1-03-02: ASCO/CAP human epidermal growth factor receptor-2 (HER2) in situ hybridization (ISH) categories evaluated by quantitative HER2 protein diagnostic methodologies: A comparative analysis

Background: In 2013, the ASCO/CAP consensus panel published updated guidelines for HER2 testing in breast cancer that modified the definition of HER2 amplification by in situ hybridization (ISH), creating five new prognostic categories (group 1: classic amplified, group 2: monosomy, group 3: co-amplified (polysomy), group 4: equivocal, and group 5: classic non-amplified). Patients determined to be ISH amplified, were considered eligible for HER2-directed therapy. Concern over whether patients from non-classic groups 2-4 would benefit from treatment has led to the recent publication of the 2018 HER2 focused update. This update has modified the criteria for interpreting these ISH categories, recommending that the final diagnosis take into consideration a combination of HER2 immunohistochemistry (IHC) and ISH results. With increased emphasis on the HER2 protein assessment, it has prompted us to quantitatively examine HER2 protein expression in the ISH categories, using two different novel technologies. Materials & Methods: A cohort of 170 cases (URMC) and 102 cases (PSHMC) of invasive breast cancers, which had previously undergone HER2 IHC and ISH testing, were selected for this study. Cases were sorted and categorized into the HER2 ISH categories defined by ASCO/CAP. HER2 protein expression was quantitatively measured in the URMC and PSHMC cohorts using a novel immunodetection methodology (streptavidin-coated Phosphor-Integrated Dot (PID) fluorescent nanoparticles), and a novel dual-antibody, proximity-binding immunoassay (HERmark® Breast Cancer Assay, Monogram Biosciences, South San Francisco, California), respectively. HER2 protein expression was compared to the HER2 FISH and IHC results by ASCO/CAP category. Results: Cases in group 1 had a significantly (p &lt; 0.01) higher average PID/cell and HERmark compared to cases in groups 2-5 (Table 1). Cases in groups 2-4 showed lower quantitative levels of HER2 protein expression, similar to the classic non-amplified cases (group 5). Group 1 was further divided into three subgroups (Table 2): Group A - ISH high-level amplified (ratio &gt; 2, HER2 &gt; 6, CEP17 &lt; 2.7), Group B - amplified with elevated CEP17 (ratio &gt; 2, CEP17 &gt; 2.7), and Group C - low-level amplified (ratio &gt; 2, HER2 &gt; 4 and &lt; 6). Group A and B had a significantly (p &lt; 0.01) higher average PID/cell and HERmark compared to Group C. Group C was more comparable to cases in groups 2-5 (Table 1). Conclusion: Our results suggest that quantitative assessment of HER2 protein expression may help to further classify cases for HER2 status for targeted therapy, supporting the 2018 ASCO/CAP recommendation that non-classic ISH results might be resolved by evaluating protein expression. Follow up studies with a larger patient cohort and dual quantitative assessment are warranted.

Average PID/cell and HERmark in ASCO category groupsASCO category groupN (URMC)PID/cell (URMC)*N (PSHMC)HERmark (PSHMC)*18888.07761.521011.20N/A32016.0213.84238.5315.95296.3208.3*averageTable 2:Average PID/cell and HERmark in subgroups of Group 1SubgroupN (URMC)PID/cell (URMC)*N (PSHMC)HERmark (PSHMC)*A24157.66465.7B34101.61044.1C3016.9329.8*average

Citation Format: Buscaglia B, Turner B, Goda H, Huang W, Leitzel K, Natori T, Nakano Y, Okada H, Sperinde J, Ali S, Vasekar M, D'Aguiar M, McMahon L, Henry J, Lipton A, Hicks D. ASCO/CAP human epidermal growth factor receptor-2 (HER2) in situ hybridization (ISH) categories evaluated by quantitative HER2 protein diagnostic methodologies: A comparative analysis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-03-02.

SGLT2 Inhibitors in Type 2 Diabetes Management: Key Evidence and Implications for Clinical Practice

Management of type 2 diabetes mellitus (T2DM) is complex and challenging, particularly for clinicians working in primary care who are faced with many competing clinical priorities. The range of available T2DM treatments has diversified significantly in recent years, generating a busy and data-rich environment in which evidence is rapidly evolving. Sodium-glucose cotransporter-2 inhibitor (SGLT2i) agents are a relatively new class of oral glucose-lowering therapy that have been available in the UK for approximately 5 years. These agents reduce the reabsorption of glucose in the kidney and increase its excretion via the urine. Conflicting messages and opinions within the clinical community have led to misconceptions concerning the efficacy, safety and appropriate position of SGLT2i therapies within the T2DM treatment pathway. To help address some of these concerns and provide advice regarding the appropriate place of these medicines in clinical practice, the Improving Diabetes Steering Committee was formed. The Committee worked together to develop this review article, providing a summary of relevant data regarding the use of SGLT2i medicines and focusing on specific considerations for appropriate prescribing within the T2DM management pathway. In addition, a benefit/risk tool has been provided (see Fig. 3) that summarises many of the aspects discussed in this review. The tool aims to support clinicians in identifying the people most likely to benefit from SGLT2i treatments, as well as situations where caution may be required.

FUNDING

Napp Pharmaceuticals Limited.

Abstract LB-324: A whole chromosome aberration phenotype in non-WNT/non-SHH tumors predicts outcome within standard-risk medulloblastomas from the HIT-SIOP-PNET4 clinical trial

Introduction: Standard-risk medulloblastoma (SR-MB; 50-60% of patients) is currently defined by the absence of high-risk (e.g. metastatic disease, large-cell/anaplastic histology, MYC amplification) disease features. 75-85% survival rates are achieved, however the identification and validation of novel prognostic biomarkers will be essential to improve risk-adapted therapies, aimed at increased survival and reduced treatment-related late-effects.

Experimental procedures: We undertook comprehensive analysis of the pan-European HIT-SIOP-PNET4 prospective clinical trial (2001-2006; age 4-21 years at diagnosis), encompassing central clinical and radiological review, and annotation of molecular pathological features to the WHO (2016) classification. Methods were developed and/or adapted to assess methylation-dependent molecular subgroup (MassArray), copy number aberrations (molecular inversion probe array) and mutational status in scant archival material previously refractory to analysis (n=136). Independent prognostic markers/predictive models for non-WNT/non-SHH patients (n=91) were identified by multivariate analyses, and validated in a representative independent cohort (n=70).

Results: WNT (n=28; 21%) and Group 4 (n=76; 56%) tumors were enriched in SR-MB compared to published disease-wide estimates. Favorable-risk WNT disease was confirmed in patients &lt;16.0 years at diagnosis. All events in SHH (4 of 17) occurred in tumors with TP53 mutation and/or chr17p loss. In non-WNT/non-SHH tumors, a novel whole chromosomal aberration (WCA) phenotype characterized by chr7 gain, chr8 loss, and/or chr11 loss, was identified in 42% of patients (38 of 91). This phenotype predicted an excellent prognosis (100% 5-year PFS) and its incorporation into novel survival models out-performed current risk-stratification schemes for SR-MB.

Conclusion: A favorable-risk WCA phenotype identifies a large proportion (42%) of non-WNT/non-SHH SR-MB patients for whom therapy de-escalation should be considered in future biomarker-driven risk-adapted clinical trials; remaining patients (58%; 68% 5-year PFS) might benefit from more intensive and/or novel therapies.

Citation Format: Tobias Goschzik, Ed C. Schwalbe, Debbie Hicks, Dominique Figarella-Branger, Francois Doz, Stefan Rutkowski, Goran Gustafsson, Birgitta Lannering, Torsten Pietsch, Steve C. Clifford. A whole chromosome aberration phenotype in non-WNT/non-SHH tumors predicts outcome within standard-risk medulloblastomas from the HIT-SIOP-PNET4 clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-324.

The mica of certain coal-measure shales in South Wales

During a study of the sources of the dusts in South Wales coal mines, carried out on behalf of the Industrial Pulmonary Disease Committee of the Medical Research Council, a mineral of the mica group was found as the main constituent of the shales overlying the coal in several mines. Of six shales investigated four were associated with anthracite, one with semi-bituminous, and one with bituminous coal. Between the coal seam itself and the shale which forms its roof there usually occurs a more coaly shale referred to locally as ‘clod’. Five of the samples investigated were isolated from ‘clods’ and one from a roof.

Abstract P2-02-10: Circulating level of GP88/Progranulin is associated with clinical outcome and overall survival in stage 4 breast cancer patients

Monitoring of disease status in metastatic breast cancer (MBC) patients is a necessary step for an optimal management of patients during and post-therapy. Imaging technologies are the methods of choice in the standard of care to monitor therapy response and disease status in MBC patients. These methods are expensive, time-consuming and have limited sensitivity for real time monitoring. Measurements of circulating tumor markers CA15-3, CA125 and CEA have contributed, albeit with limitation, minimally invasive methods for MBC disease management. It is our hypothesis that measuring biomarkers involved in tumor biological processes may provide better evaluation of the disease state and thus aid real-time clinical management of MBC patients. Thus, addition of such new circulating disease biomarkers may improve the management of MBC patients. The 88kDa glycoprotein Progranulin (GP88/PGRN) fit these criteria. GP88/PGRN is expressed in tumor tissue and not in normal mammary tissue counterpart and secreted in the circulation of BC patients. Biological studies have established GP88/PGRN as a critical driver of BC cell proliferation, survival, invasiveness and drug resistance. Clinical studies have demonstrated that high tumor GP88/PGRN expression was prognostic for recurrence and that breast cancer patients had a statistically elevated GP88/PGRN serum level compared to healthy individuals. In the present study, we examined whether GP88/PGRN serum levels were elevated in MBC patients and whether GP88/PGRN circulating levels were correlated with patient clinical outcome and overall survival.

Under an IRB approved protocol at the University of Maryland Greenebaum Comprehensive Cancer Center, 101 stage 4 BC patients undergoing standard of care therapy and meeting the inclusion criteria were consented and enrolled. MBC patients' demographics, clinical and disease characteristics and therapies were collected as part of the study. Blood samples were collected from each patient at specific times at follow-up visits during and post-therapy. The prepared serum was stored at -80C until tested for GP88 using a GP88 enzyme linked immunoassay developed in our laboratory.

Statistical analysis using Kaplan-Meier functions established whether there was a correlation between GP88/PGRN serum level and overall survival in MBC patients. MBC patients with distinct survival characteristics (P=0.0002) could be stratified based on their circulating GP88/PGRN levels. Analysis of this association was carried out in MBC patients based on their age, race, tumor characteristics, receptor status and metastatic burden (number and sites of metastasis) and will be reported. We conclude that circulating levels of GP88/PGRN in MBC patients are correlated with overall survival and that monitoring circulating GP88/PGRN levels would provide additional information and valuable insight into real-time MBC disease status.

This work was supported by grant R43 CA 210817-01A1 to GS.

Citation Format: Serrero G, Hawkins D, Hicks D, Rosenblatt P, Tait N, Yue B, Tkaczuk K. Circulating level of GP88/Progranulin is associated with clinical outcome and overall survival in stage 4 breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-02-10.

Development of a targeted sequencing approach to identify prognostic, predictive and diagnostic markers in paediatric solid tumours

The implementation of personalised medicine in childhood cancers has been limited by a lack of clinically validated multi-target sequencing approaches specific for paediatric solid tumours. In order to support innovative clinical trials in high-risk patients with unmet need, we have developed a clinically relevant targeted sequencing panel spanning 311 kb and comprising 78 genes involved in childhood cancers. A total of 132 samples were used for the validation of the panel, including Horizon Discovery cell blends (n=4), cell lines (n=15), formalin-fixed paraffin embedded (FFPE, n=83) and fresh frozen tissue (FF, n=30) patient samples. Cell blends containing known single nucleotide variants (SNVs, n=528) and small insertion-deletions (indels n=108) were used to define panel sensitivities of ≥98% for SNVs and ≥83% for indels [95% CI] and panel specificity of ≥98% [95% CI] for SNVs. FFPE samples performed comparably to FF samples (n=15 paired). Of 95 well-characterised genetic abnormalities in 33 clinical specimens and 13 cell lines (including SNVs, indels, amplifications, rearrangements and chromosome losses), 94 (98.9%) were detected by our approach. We have validated a robust and practical methodology to guide clinical management of children with solid tumours based on their molecular profiles. Our work demonstrates the value of targeted gene sequencing in the development of precision medicine strategies in paediatric oncology.

Minimal methylation classifier (MIMIC): A novel method for derivation and rapid diagnostic detection of disease-associated DNA methylation signatures

Rapid and reliable detection of disease-associated DNA methylation patterns has major potential to advance molecular diagnostics and underpin research investigations. We describe the development and validation of minimal methylation classifier (MIMIC), combining CpG signature design from genome-wide datasets, multiplex-PCR and detection by single-base extension and MALDI-TOF mass spectrometry, in a novel method to assess multi-locus DNA methylation profiles within routine clinically-applicable assays. We illustrate the application of MIMIC to successfully identify the methylation-dependent diagnostic molecular subgroups of medulloblastoma (the most common malignant childhood brain tumour), using scant/low-quality samples remaining from the most recently completed pan-European medulloblastoma clinical trial, refractory to analysis by conventional genome-wide DNA methylation analysis. Using this approach, we identify critical DNA methylation patterns from previously inaccessible cohorts, and reveal novel survival differences between the medulloblastoma disease subgroups with significant potential for clinical exploitation.

Exome sequences versus sequential gene testing in the UK highly specialised Service for Limb Girdle Muscular Dystrophy

BACKGROUND

Limb girdle muscular dystrophies are a group of rare and genetically heterogeneous diseases that share proximal weakness as a common feature; however they are often lacking very specific phenotypic features to allow an accurate differential diagnosis based on the clinical signs only, limiting the diagnostic rate using phenotype driven genetic testing. Next generation sequencing provides an opportunity to obtain molecular diagnoses for undiagnosed patients, as well as identifying novel genetic causes of muscle diseases. We performed whole exome sequencing (WES) on 104 affected individuals from 75 families in who standard gene by gene testing had not yielded a diagnosis. For comparison we also evaluated the diagnostic rate using sequential gene by gene testing for 91 affected individuals from 84 families over a 2 year period.

RESULTS

Patients selected for WES had undergone more extensive prior testing than those undergoing standard genetic testing and on average had had 8 genes screened already. In this extensively investigated cohort WES identified the genetic diagnosis in 28 families (28/75, 37%), including the identification of the novel gene ZAK and two unpublished genes. WES of a single affected individual with sporadic disease yielded a diagnosis in 13/38 (34%) of cases. In comparison, conventional gene by gene testing provided a genetic diagnosis in 28/84 (33%) families. Titinopathies and collagen VI related dystrophy were the most frequent diagnoses made by WES. Reasons why mutations in known genes were not identified previously included atypical phenotypes, reassignment of pathogenicity of variants, and in one individual mosaicism for a COL6A1 mutation which was undetected by prior direct sequencing.

CONCLUSION

WES was able to overcome many limitations of standard testing and achieved a higher rate of diagnosis than standard testing even in this cohort of extensively investigated patients. Earlier application of WES is therefore likely to yield an even higher diagnostic rate. We obtained a high diagnosis rate in simplex cases and therefore such individuals should be included in exome or genome sequencing projects. Disease due to somatic mosaicism may be increasingly recognised due to the increased sensitivity of next generation sequencing techniques to detect low level mosaicism.