Functional Electrochemistry: On-Nerve Assessment of Electrode Materials for Electrochemistry and Functional Neurostimulation.

Emerging therapies in bioelectronic medicine highlight the need for deeper understanding of electrode material performance in the context of tissue stimulation. Electrochemical properties are characterized on the benchtop, facilitating standardization across experiments. On-nerve electrochemistry differs from benchtop characterization and the relationship between electrochemical performance and nerve activation thresholds are not commonly established. This relationship is important in understanding differences between electrical stimulation requirements and electrode performance. We report functional electrochemistry as a follow-up to benchtop testing, describing a novel experimental approach for evaluating on-nerve electrochemical performance in the context of nerve activation. An ex-vivo rat sciatic nerve preparation was developed to quantify activation thresholds of fiber subtypes and electrode material charge injection limits for platinum iridium, iridium oxide, titanium nitride and PEDOT. Finally, we address experimental complexities arising in these studies, and demonstrate statistical solutions that support rigorous material performance comparisons for decision making in neural interface development.

Thalamic connectivity topography in newborns with spina bifida: association with neurological functional level but not developmental outcome at 2 years.

Spina bifida affects spinal cord and cerebral development, leading to motor and cognitive delay. We investigated whether there are associations between thalamocortical connectivity topography, neurological function, and developmental outcomes in open spina bifida. Diffusion tensor MRI was used to assess thalamocortical connectivity in 44 newborns with open spina bifida who underwent prenatal surgical repair. We quantified the volume of clusters formed based on the strongest probabilistic connectivity to the frontal, parietal, and temporal cortex. Developmental outcomes were assessed using the Bayley III Scales, while the functional level of the lesion was assessed by neurological examination at 2 years of age. Higher functional level was associated with smaller thalamo-parietal, while lower functional level was associated with smaller thalamo-temporal connectivity clusters (Bonferroni-corrected P < 0.05). Lower functional levels were associated with weaker thalamic temporal connectivity, particularly in the ventrolateral and ventral anterior nuclei. No associations were found between thalamocortical connectivity and developmental outcomes. Our findings suggest that altered thalamocortical circuitry development in open spina bifida may contribute to impaired lower extremity function, impacting motor function and independent ambulation. We hypothesize that the neurologic function might not merely be caused by the spinal cord lesion, but further impacted by the disruption of cerebral neuronal circuitry.

Motor function outcomes in children with open prenatal repair of Spina Bifida Aperta at 36-month follow-up: The Zurich cohort.

PURPOSE: This study aimed to describe outcomes of motor function with a special focus on ambulation ability at 36 months among children with open prenatal repair of spina bifida aperta (SB). METHODS: A prospective cohort study was conducted including 87 patients with open prenatal repair of SB at the investigating center born between 2010 and 2018. Anatomic lesion level and motor function level in the neonatal period, as well as motor function level, ambulation status, and use of orthotics and assistive devices at 36 months were assessed. RESULTS: At 36 months, ambulation was assessed in 86 children; of those, 86% (n = 74) were ambulating. Independent of ambulation, orthotics were worn in 81.6% (71/87) and assistive devices in 47.1% (41/87). Children with a lower lumbar or sacral motor function level were the first to reach independent ambulation and were more likely to ambulate at 36 months than children with higher motor function levels (p = < .001). The anatomic lesion level determined on the neonatal MRI correlated with ambulation status at 36 months (p = < 0.001). CONCLUSION: At 36 months, most children with open prenatal repair for SB showed favourable ambulation status. However, most still used assistive devices or orthotics. Anatomic lesion level on neonatal MRI, motor function level during the neonatal period, and motor function level at 36 months were associated with ambulation status at 36 months.

M-Sign in Middle Cerebral Artery Doppler Waveforms: A Sign of Fetal Vasoconstriction Before and After Open Fetal Spina Bifida Repair.

BACKGROUND: Increased pulse wave reflection in the fetal arterial system, illustrated by a second systolic peak (M-sign) in middle cerebral artery (MCA) Doppler waveforms, allows interpretation of fetal systemic vasoconstriction. Little is known about fetal vascular regulation during fetal spina bifida (fSB) repair. Therefore, the aim of this study was to analyze MCA-Doppler waveform changes before, during, and after fSB repair. PATIENTS AND METHODS: 31 pregnant women who underwent fSB repair were included. Fetal MCA-Doppler waveforms were prospectively analyzed before, during and after fSB repair, and categorized as follows: normal systolic downslope, systolic shoulder, second systolic peak (M-sign), and concave systolic downslope. These MCA waveforms were related to maternal and fetal characteristics, to anesthetic medication, and to umbilical artery (UA) waveforms. RESULTS: Before fSB repair, all fetuses repeatedly presented M-signs. After initiation of desflurane for general anesthesia, systolic shoulder and the M-sign vanished in 24/31 (78%) fetuses and 19/31 (61%) showed transient UA ARED flow. A significant association between these two Doppler findings was found (p=0.007). After fSB repair, signs of increased pulse wave reflection reappeared but resolved over time (23 days ± 20, SD) in all fetuses. CONCLUSION: Both fSB and intrauterine repair influence fetal vascular regulation. This phenomenon can be illustrated by MCA-Doppler waveforms. While anesthetic agents transiently eliminated M-signs and often provoked a UA ARED flow, fSB repair finally led to normalization of MCA-Doppler waveforms indicating return to normal fetal vascular regulation.

The prolyl hydroxylase inhibitor GSK1120360A reduces early brain injury, but protection is not maintained in a neonatal rat model of hypoxic ischaemic encephalopathy.

Hypoxic-ischemic encephalopathy (HIE) in newborns is associated with high morbidity and mortality, with many babies suffering long-term neurological deficits. Currently, treatment options are limited to therapeutic hypothermia, which is not appropriate for use in all babies. Previous studies have shown protective effects of increasing the transcription factor-hypoxia-inducible factor-1 (HIF-1) in animal models, by using mild hypoxia or compounds that act as prolyl hydroxylase inhibitors (PHIs). Here, we aimed to examine the neuroprotective actions of an orally active, small molecule PHI, GSK1120360A in a neonatal rat model of hypoxia-ischemia (HI) compared to another PHI, desferrioxamine (DFX). Sprague-Dawley rats underwent HI surgery on postnatal day 7 (P7), where unilateral carotid artery occlusion was performed followed by hypoxia (8% oxygen, 3 h). Initial testing showed that GSK1120360A and erythropoietin levels were detectable in plasma at 6 h following oral exposure to GSK1120360A. For the short-term neuroprotection study, pups were assigned to receive either saline (s.c), desferrioxamine (DFX-200 mg/kg, s.c), methylcellulose (1%, oral) or GSK1120360A (30 mg/kg, oral) immediately after HI. Histological analysis showed that GSK1120360A in this setting reduced brain injury size 7 days after HI, compared to the methylcellulose vehicle control group. DFX had no significant effect on injury size compared to saline group at the same 7 day timepoint. In the long-term neuroprotection study, pups were randomly assigned to be administered methylcellulose (1%, oral) or GSK1120360A (30 mg/kg, oral) immediately after HI. On P42, rats underwent behavioural testing using the forelimb grip strength, grid walking and novel object recognition tasks, and brains were collected for histological analysis. Long-term behavioural deficits were observed in grid walking, grip strength and novel object recognition tests after HI which were not improved in the GSK1120360A treatment group compared to the methylcellulose group. Similarly, there was no improvement in injury size on P42 in the GSK1120360A study group compared to the methylcellulose group. Here, we have shown that GSK1120360A can reduce brain injury at 7 days but that this neuroprotective benefit is not maintained when examined at 5 weeks after HI.

Immune disease risk variants regulate gene expression dynamics during CD4+ T cell activation.

During activation, T cells undergo extensive gene expression changes that shape the properties of cells to exert their effector function. Understanding the regulation of this process could help explain how genetic variants predispose to immune diseases. Here, we mapped genetic effects on gene expression (expression quantitative trait loci (eQTLs)) using single-cell transcriptomics. We profiled 655,349 CD4+ T cells, capturing transcriptional states of unstimulated cells and three time points of cell activation in 119 healthy individuals. This identified 38 cell clusters, including transient clusters that were only present at individual time points of activation. We found 6,407 genes whose expression was correlated with genetic variation, of which 2,265 (35%) were dynamically regulated during activation. Furthermore, 127 genes were regulated by variants associated with immune-mediated diseases, with significant enrichment for dynamic effects. Our results emphasize the importance of studying context-specific gene expression regulation and provide insights into the mechanisms underlying genetic susceptibility to immune-mediated diseases.

The repurposing of Tebipenem pivoxil as alternative therapy for severe gastrointestinal infections caused by extensively drug-resistant Shigella spp.

Background: Diarrhoea remains one of the leading causes of childhood mortality globally. Recent epidemiological studies conducted in low-middle income countries (LMICs) identified Shigella spp. as the first and second most predominant agent of dysentery and moderate diarrhoea, respectively. Antimicrobial therapy is often necessary for Shigella infections; however, we are reaching a crisis point with efficacious antimicrobials. The rapid emergence of resistance against existing antimicrobials in Shigella spp. poses a serious global health problem. Methods: Aiming to identify alternative antimicrobial chemicals with activity against antimicrobial resistant Shigella, we initiated a collaborative academia-industry drug discovery project, applying high-throughput phenotypic screening across broad chemical diversity and followed a lead compound through in vitro and in vivo characterisation. Results: We identified several known antimicrobial compound classes with antibacterial activity against Shigella. These compounds included the oral carbapenem Tebipenem, which was found to be highly potent against broadly susceptible Shigella and contemporary MDR variants for which we perform detailed pre-clinical testing. Additional in vitro screening demonstrated that Tebipenem had activity against a wide range of other non-Shigella enteric bacteria. Cognisant of the risk for the development of resistance against monotherapy, we identified synergistic behaviour of two different drug combinations incorporating Tebipenem. We found the orally bioavailable prodrug (Tebipenem pivoxil) had ideal pharmacokinetic properties for treating enteric pathogens and was effective in clearing the gut of infecting organisms when administered to Shigella-infected mice and gnotobiotic piglets. Conclusions: Our data highlight the emerging antimicrobial resistance crisis and shows that Tebipenem pivoxil (licenced for paediatric respiratory tract infections in Japan) should be accelerated into human trials and could be repurposed as an effective treatment for severe diarrhoea caused by MDR Shigella and other enteric pathogens in LMICs. Funding: Tres Cantos Open Lab Foundation (projects TC239 and TC246), the Bill and Melinda Gates Foundation (grant OPP1172483) and Wellcome (215515/Z/19/Z).

Determination of Anatomical Levels in Spina Bifida Fetuses with Ultrasound and MRI.

PURPOSE: The goal of this study was to assess the accuracy of prenatal anatomical level determination by ultrasound (US) and magnetic resonance imaging (MRI) by analyzing the congruence with the "true" anatomical level identified by postnatal MRI. PATIENTS AND METHODS: The first 60 patients undergoing fetal myelomeningocele surgery at The Zurich Center for Fetal Diangosis and Therapy were included in this study. Anatomical levels (i. e., first dysraphic vertebra) determined by prenatal US and MRI were compared to postnatal MRI. The level of agreement between the imaging modalities was evaluated with a Cohen's kappa test. Results > 0.6 were interpreted as good agreement, > 0.8 as excellent. RESULTS: The exact congruence between prenatal US and MRI compared to postnatal MRI was 33 % and 48 %, respectively, for an accuracy within one level difference of 80 % and 90 %, and within two levels difference of 95 % and 98 %, respectively. The level of agreement of prenatal US and MRI compared to postnatal MRI was 0.62 and 0.79, respectively. Most of the prenatally incorrectly assigned levels were assigned too high (worse) than the "true" level (US 88 % vs. MRI 65 %). CONCLUSION: Reliable exact prenatal level determination by US and MRI is not possible. However, the prenatal determination of the anatomical level of the lesion is good within one level margin of error. Prenatal US as well as MRI demonstrate a systematic error towards higher levels. The above considerations must be integrated into prenatal counselling.

Impact of Brain Malformations on Neurodevelopmental Outcome in Children with a History of Prenatal Surgery for Open Spina Bifida.

INTRODUCTION: This retrospective study investigates brain malformations and their impact on neurodevelopmental outcome in children after prenatal surgery for spina bifida (SB). METHODS: Sixty-one patients were included. On neonatal MRI, SB-associated brain malformations were assessed. Ventricular size, ventriculo-peritoneal shunt (VPS), and endoscopic third ventriculostomy (ETV) were also documented. Neurodevelopment was assessed with the Bayley-III and correlated with brain malformations, ventricular size, and VPS/ETV placement. RESULTS: Chiari II malformation was detected in all patients. Corpus callosum (CC) abnormality was noted in 40%, heterotopies in 35%, and cerebellar parenchymal defects in 11%. 96% had ventriculomegaly; in 46%, VPS/ETV was performed. Cognitive and language testing yielded results in the low-average range (Bayley-III: Cognitive Composite Score 93.6, Language Composite Score 89.7), motor testing was below average (Motor Composite Score 77.4). CC abnormalities, heterotopies, and cerebellar defects were not associated with poorer Bayley-III scores, whereas patients with severe ventriculomegaly performed poorer in all subtests, significantly so for the language composite score. Patients requiring intervention for hydrocephalus had significantly lower scores in motor testing. DISCUSSION/CONCLUSION: Additional brain malformations in open SB do not seem to have an impact on cognitive function at 2 years of age. Severe ventriculomegaly is a risk factor for poorer cognitive outcome; hydrocephalus surgery adds an additional risk for delayed motor function.

Early childhood neurodevelopmental outcome after open prenatal spina bifida aperta repair.

AIM: To investigate neurodevelopmental outcome of children with open prenatal spina bifida aperta (SBA) repair. METHOD: Prenatal SBA repair was performed in 130 fetuses at the Zurich Center between 2010 and 2019. Seventy-seven children underwent 1 year assessment with the Griffiths Mental Developmental Scales (Griffiths) and 65 with the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) at 2 years. Anatomical and functional level and ambulation status were assessed. Descriptive statistics and multiple linear regression analyses for risk factors were performed. RESULTS: The Bayley-III cognition composite score in children with prenatal SBA repair was within normal limits but lower compared to population norms (mean=95.15, SD=14.683 vs norm=100, SD=15, p=0.01). Fine motor development (mean=9.58, SD=2.744, p=0.227) was typical while gross motor development was lower than the norm (mean=3.02, SD=2.758 vs norm=10, SD=3, p<0.001). Griffiths developmental quotient subscales correlated significantly with corresponding Bayley-III scores (all p<0.001, r=0.519-0.594). At 2 years, 50.8% could walk. INTERPRETATION: Children with non-trial open prenatal SBA repair show favourable cognitive outcome in the low-average range at 1 and 2 years of age. While gross motor function remained delayed, fine motor function was age appropriate. The correlation between Griffiths and Bayley-III allows a prediction about neurodevelopmental outcome at the age of 1 year. What this paper adds Children with non-trial open prenatal spina bifida repair show favourable cognitive outcome. Gross motor function remains impaired, while fine motor function is age appropriate. At 2 years of age, 50.8% of children were walking. Neurodevelopmental testing correlated between 1 (Griffiths Mental Developmental Scales) and 2 (Bayley Scales of Infant and Toddler Development, Third Edition) years.

Fetal surgery for spina bifida in Zurich: results from 150 cases.

PURPOSE: Over the past 10 years, over 150 fetal spina bifida surgeries were performed at the Zurich Center for Fetal Diagnosis and Therapy. This study looks at surrogates for success and failure of this approach. METHODS: We focused on key outcome parameters including hydrocephalus shunt rate at one year, bladder control at 4, independent ambulation at 3 years, and maternal, fetal, and neonatal complications. RESULTS: From the first 150 patients undergoing fetal surgery for spina bifida, 148 (98.7%) were included in the study. Maternal-fetal surgery was uneventful in 143/148 (97%) cases. Intraoperative problems included resuscitation in 4/148 fetuses (2.7%). 1/148 fetuses (0.7%) died on postoperative day 4. Maternal complications included chorioamniotic membrane separation in 22/148 (15%), lung embolism in 3/148 (2.1%), chorioamnionitis in 2/148 (1.4%), AV-block III and uterine rupture in 1/148 each (0.7%). 1/148 (0.7%) newborn death was recorded. Hindbrain herniation was identified preoperatively in 132/148 (90%) fetuses and resolved completely in 119/132 (90%). At one year, 39/106 (37%) children had required a CSF diversion. At 4 years, 4/34 patients (12%) had normal bladder control. At 3 years, 48/57 (84%) walked independently. CONCLUSION: A majority of patients benefitted from prenatal intervention, in that the shunt rate was lower and the rates of continent and walking patients were higher than reported with postnatal care.

Pathophysiological aspects of posterior reversible encephalopathy syndrome in two peritoneal-dialyzed children.

Hypotension, blood pressure fluctuation, and endothelial impairment indicate possible additive pathophysiological aspects in the development of posterior reversible encephalopathy syndrome in children on peritoneal dialysis.

Genotype-phenotype spectrum in isolated and syndromic nanophthalmos.

PURPOSE: To (i) describe a series of patients with isolated or syndromic nanophthalmos with the underlying genetic causes, including novel pathogenic variants and their functional characterization and (ii) to study the association of retinal dystrophy in patients with MFRP variants, based on a detailed literature review of genotype-phenotype correlations. METHODS: Patients with nanophthalmos and available family members received a comprehensive ophthalmological examination. Genetic analysis was based on whole-exome sequencing and variant calling in core genes including MFRP, BEST1, TMEM98, PRSS56, CRB1, GJA1, C1QTNF5, MYRF and FAM111A. A minigene assay was performed for functional characterization of a splice site variant. RESULTS: Seven patients, aged between three and 65 years, from five unrelated families were included. Novel pathogenic variants in MFRP (c.497C>T, c.899-3C>A, c.1180G>A), and PRSS56 (c.1202C>A), and a recurrent de novo variant in FAM111A (c.1706G>A) in a patient with Kenny-Caffey syndrome type 2, were identified. In addition, we report co-inheritance of MFRP-related nanophthalmos and ADAR-related Aicardi-Goutières syndrome. CONCLUSION: Nanophthalmos is a genetically heterogeneous condition, and the severity of ocular manifestations appears not to correlate with variants in a specific gene. However, retinal dystrophy is only observed in patients harbouring pathogenic MFRP variants. Furthermore, heterozygous carriers of MFRP and PRSS56 should be screened for the presence of high hyperopia. Identifying nanophthalmos as an isolated condition or as part of a syndrome has implications for counselling and can accelerate the interdisciplinary care of patients.

Single-cell transcriptomics identifies an effectorness gradient shaping the response of CD4+ T cells to cytokines.

Naïve CD4+ T cells coordinate the immune response by acquiring an effector phenotype in response to cytokines. However, the cytokine responses in memory T cells remain largely understudied. Here we use quantitative proteomics, bulk RNA-seq, and single-cell RNA-seq of over 40,000 human naïve and memory CD4+ T cells to show that responses to cytokines differ substantially between these cell types. Memory T cells are unable to differentiate into the Th2 phenotype, and acquire a Th17-like phenotype in response to iTreg polarization. Single-cell analyses show that T cells constitute a transcriptional continuum that progresses from naïve to central and effector memory T cells, forming an effectorness gradient accompanied by an increase in the expression of chemokines and cytokines. Finally, we show that T cell activation and cytokine responses are influenced by the effectorness gradient. Our results illustrate the heterogeneity of T cell responses, furthering our understanding of inflammation.

Benchmarking against the MOMS Trial: Zurich Results of Open Fetal Surgery for Spina Bifida.

INTRODUCTION: The Management of Myelomeningocele Study, a.k.a. the MOMS trial, was published in 2011 in the New England Journal of Medicine. This prospective randomized controlled trial proved to be a milestone publication that provided definitive evidence that fetal surgery is a novel standard of care for select fetuses with spina bifida aperta (SB). The goal of our study is to assess whether our center can match these benchmark results. MATERIALS AND METHODS: Our study was conducted according to the MOMS protocol using the same inclusion and exclusion criteria and looked at the same outcome parameters that were used in the MOMS trial. Zurich and MOMS results were compared. RESULTS: We enrolled 20 patients between December 2010 and May 2015 all of whom underwent fetal surgery for SB. Among 51 different outcome variables, there were only 3 favorable (multiplicity-adjusted) significant differences (gestational age at birth, hindbrain herniation, and psychomotor development). There were no statistically significant differences regarding any other parameters. CONCLUSION: Our findings confirm that rigorous apprenticeship, training, and comprehensive prospective data collection enable centers like the Zurich Center for Fetal Diagnosis and Therapy to achieve benchmark results for open fetal surgery for myelomeningocele and myeloschisis. These results justify the existence and continuation of our program. Outcome documentation is an essential element of quality management. It is medically and ethically fundamental for fetal medicine and surgery centers offering high-end innovative medical care.

Chromatin activity at GWAS loci identifies T cell states driving complex immune diseases.

Immune-disease-associated variants are enriched in active chromatin regions of T cells and macrophages. However, whether these variants function in specific cell states is unknown. Here we stimulated T cells and macrophages in the presence of 13 cytokines and profiled active and open chromatin regions. T cell activation induced major chromatin remodeling, while the presence of cytokines fine-tuned the magnitude of changes. We developed a statistical method that accounts for subtle changes in the chromatin landscape to identify SNP enrichment across cell states. Our results point towards the role of immune-disease-associated variants in early rather than late activation of memory CD4+ T cells, with modest differences across cytokines. Furthermore, variants associated with inflammatory bowel disease are enriched in type 1 T helper (TH1) cells, whereas variants associated with Alzheimer's disease are enriched in different macrophage cell states. Our results represent an in-depth analysis of immune-disease-associated variants across a comprehensive panel of activation states of T cells and macrophages.

Benchmarking network propagation methods for disease gene identification.

In-silico identification of potential target genes for disease is an essential aspect of drug target discovery. Recent studies suggest that successful targets can be found through by leveraging genetic, genomic and protein interaction information. Here, we systematically tested the ability of 12 varied algorithms, based on network propagation, to identify genes that have been targeted by any drug, on gene-disease data from 22 common non-cancerous diseases in OpenTargets. We considered two biological networks, six performance metrics and compared two types of input gene-disease association scores. The impact of the design factors in performance was quantified through additive explanatory models. Standard cross-validation led to over-optimistic performance estimates due to the presence of protein complexes. In order to obtain realistic estimates, we introduced two novel protein complex-aware cross-validation schemes. When seeding biological networks with known drug targets, machine learning and diffusion-based methods found around 2-4 true targets within the top 20 suggestions. Seeding the networks with genes associated to disease by genetics decreased performance below 1 true hit on average. The use of a larger network, although noisier, improved overall performance. We conclude that diffusion-based prioritisers and machine learning applied to diffusion-based features are suited for drug discovery in practice and improve over simpler neighbour-voting methods. We also demonstrate the large impact of choosing an adequate validation strategy and the definition of seed disease genes.

Inclusion Cysts after Fetal Spina Bifida Repair: A Third Hit?

INTRODUCTION: Fetal spina bifida repair (fSBR) has proven effective in the reversibility of hindbrain herniation, lower rate of shunt-dependent hydrocephalus, and independent ambulation. Besides distinct advantages, there are also concerns related to fSBR. One of these is the postnatal occurrence of inclusion cysts (IC). METHODS: In a prospective study, 48 children who underwent fSBR were followed up. Postnatal assessment included clinical examination, cystometry, and spinal MRI. Indication for IC resection was the evidence of a spinal mass on MRI in the presence of deteriorating motor or bladder function, pain, or considerable growth of the IC. RESULTS: Fourteen children (30%) developed IC, all within the first 2 years of life. Six children underwent IC resection; 4 children due to deteriorating function, 2 children due to doubling of the mass on MRI within 1 year. Following IC resection, 4/6 children (67%) demonstrated altered motor function and 6 children (100%) were diagnosed with neurogenic bladder dysfunction. CONCLUSIONS: Systematic follow-up of patients with a history of fSBR revealed a high incidence of IC. Whether these are of dysembryogenic or iatrogenic origin, remains unclear. Since both IC per se and IC resection may lead to loss of neurologic function, IC can be considered a "third hit".

Pathway-based dissection of the genomic heterogeneity of cancer hallmarks' acquisition with SLAPenrich.

Cancer hallmarks are evolutionary traits required by a tumour to develop. While extensively characterised, the way these traits are achieved through the accumulation of somatic mutations in key biological pathways is not fully understood. To shed light on this subject, we characterised the landscape of pathway alterations associated with somatic mutations observed in 4,415 patients across ten cancer types, using 374 orthogonal pathway gene-sets mapped onto canonical cancer hallmarks. Towards this end, we developed SLAPenrich: a computational method based on population-level statistics, freely available as an open source R package. Assembling the identified pathway alterations into sets of hallmark signatures allowed us to connect somatic mutations to clinically interpretable cancer mechanisms. Further, we explored the heterogeneity of these signatures, in terms of ratio of altered pathways associated with each individual hallmark, assuming that this is reflective of the extent of selective advantage provided to the cancer type under consideration. Our analysis revealed the predominance of certain hallmarks in specific cancer types, thus suggesting different evolutionary trajectories across cancer lineages. Finally, although many pathway alteration enrichments are guided by somatic mutations in frequently altered high-confidence cancer genes, excluding these driver mutations preserves the hallmark heterogeneity signatures, thus the detected hallmarks' predominance across cancer types. As a consequence, we propose the hallmark signatures as a ground truth to characterise tails of infrequent genomic alterations and identify potential novel cancer driver genes and networks.