Biology subjects

Treger, T. D.

Publications and source records attributed to Treger, T. D..

4 recordsLinked to original sources

bioRxiv2025

Extensive and differential platinum chemotherapy mutagenesis in children

Childhood cancer survivors often develop long-term adverse effects, which may be caused by direct mutagenesis of cytotoxic agents. Some of these agents generate distinctive DNA imprints (mutational signatures), as exemplified by platinum chemotherapeutics. Here, we examined chemotherapy mutagenesis in paediatric tissues by deploying a duplex sequencing method (NanoSeq), which enables mutation calling from single DNA molecules. We surveyed whole genomes of paediatric liver, blood and other tissues, obtained from surgical resections and at post-mortem. Platinum signatures pervaded all tissues extensively, elevating mutation burdens of paediatric tissues to levels seen in adults. Remarkably, we found a tissue-specific mutational signature in the liver. We examined the functional potential of mutations by gene focused NanoSeq, which revealed that platinum agents cause a vast repertoire of cancer causing variants across normal tissues, such as leukaemogenic mutations in blood. This finding may conceivably link cancer treatment in childhood to mutation-driven long term sequelae.

cancer biology↗

bioRxiv2025

Single cell transcriptional evolution of myeloid leukaemia of Down syndrome

Children with Down syndrome have a 150-fold increased risk of developing myeloid leukaemia (ML-DS). Unusually for a childhood leukaemia, ML-DS arises from a preleukaemic state, termed transient abnormal myelopoiesis (TAM), via a conserved sequence of mutations. Here, we examined the relationship between the genetic and transcriptional evolution of ML-DS from natural variation; a rich collection of primary patient samples and fetal tissues with a range of constitutional karyotypes. We distilled transcriptional consequences of each genetic step in ML-DS evolution, utilising single cell mRNA sequencing, complemented by phylogenetic analyses in progressive disease. We found that transcriptional changes induced by the TAM-defining GATA1 mutations are retained in, and account for most of the ML-DS transcriptome. The GATA1 transcriptome pervaded all stages of ML-DS, including progressive disease that had undergone genetic evolution. Our approach delineates the transcriptional evolution of ML-DS and provides an analytical blueprint for distilling consequences of mutations within their pathophysiological context.

cancer biology↗

bioRxiv2024

Cancer-independent, second somatic NF1 mutation of normal tissues in neurofibromatosis type 1

INTRODUCTIONCancer predisposition syndromes mediated by recessive cancer genes generate tumours via somatic variants (second hits) in the unaffected allele. Second hits may or may not be sufficient for neoplastic transformation. Here, we performed whole genome and exome sequencing on 479 tissue biopsies from a child with neurofibromatosis type 1, a multi-system cancer-predisposing syndrome mediated by constitutive monoallelic NF1 inactivation. We identified multiple independent NF1 driver variants in histologically normal tissues, but not in 610 biopsies from two non-predisposed children. We corroborated this finding using targeted duplex sequencing, including a further nine adults with the same syndrome. Overall, truncating NF1 mutations were under positive selection in normal tissues from individuals with neurofibromatosis type 1. We demonstrate that normal tissues in neurofibromatosis type 1 commonly harbour second hits in NF1, the extent and pattern of which may underpin the syndromes cancer phenotype.

cancer biology↗

bioRxiv2024

Subtype-specific Patterns of Evolution and Clinically Relevant Genomic Instability in Wilms Tumour

BackgroundUnderstanding cancer evolution is fundamental to predicting cancer progression. However, the evolution of paediatric cancers is still under-researched. Large cohorts of patients are required to determine consistent evolutionary trajectories that shed light on key steps in cancer development and reveal underlying biology, especially in rare cancers. Additionally, well annotated clinical data is necessary for determining if evolutionary biomarkers are predictive of patient outcome. MethodsWe performed detailed evolutionary analysis of 64 paediatric kidney cancers, including 60 Wilms tumours (WT), using DNA microarrays and, in a subset of 30 patients, a WT-specific targeted sequencing assay, to detect copy number alterations (CNA) and mutations, respectively. By analysing multiple tissue samples in the majority of cases we could detect mutation heterogeneity in each tumour. We reconstructed clones across the cohort and described their phylogenetic histories, in addition to detecting mirrored subclonal allelic imbalance. ResultsOur results highlight pervasive evidence of parallel evolution in WTs affecting CNAs, and CTNNB1 and TP53 mutations. Furthermore, we demonstrate that stromal-type WTs often evolve from a consistent series of events (WT1 mutation, 11p uniparental disomy and CTNNB1 mutation) and we suggest that 19q uniparental disomy is an important ancestral event in both epithelial and diffuse anaplastic WTs. Finally, we propose the total number of evolutionary CNA events as a prognostic biomarker in WTs for event-free survival, particularly in high-risk WT. ConclusionsOverall, this study sheds light on the evolution of the most common paediatric kidney cancer and links evolutionary analysis to fundamental clinical and biological questions in a large cohort of WTs. We conclude that histological subtypes of WT are often defined by consistent evolutionary sequences. We present evidence that a key marker of evolvability, namely CNA diversity measured phylogenetically across multiple tumour sites, is prognostic of patient outcome and should be considered for clinical use to detect the most aggressive blastemal and diffuse anaplastic type WTs.

cancer biology↗