Abstract Normal aged tissues are thought to exist as a patchwork of mutant clones. However, the relevance of driver mutations in normal tissue in terms of cancer initiation has not been well described. Here, we sought a quantitative understanding of how different cancer drivers achieve an age-related mutational footprint in the human colonic epithelium and to relate the clonal behaviours they generate to cancer risk. Metanalysis of contemporary multiregional sampling studies of colorectal tumours revealed many of the weak or moderate cancer drivers are trunk mutations present in the last common ancestor from which cancers arise. To study the processes by which such driver mutations could contribute to cancer predisposition, immunohistochemistry was used to detect PTEN, SMAD4 and ARID1A deficient clones in normal colon FFPE surgical resection samples (N=182 patients). Age-related changes in clone size and frequency identified positive biases in clone dynamics that acted to increase the mutational footprint for ARID1A and PTEN but not SMAD4. In vitro engineered monoallelic loss of PTEN and ARID1A implicated specific altered downstream pathways and acquired pro-oncogenic cellular fates corresponding to haploinsufficiency for these genes. In situ analysis confirmed enhanced proliferation in both PTEN and ARID1A deficient clones and creation of an immune exclusive microenvironment associated with ARID1A deficiency. The behaviours resulting from haploinsufficiency of PTEN and ARID1A exemplify how priming of the tissue through somatic mosaicism could contribute alternative combinations of genetic events leading to transformation.
Objective: The objective of this study was to analyze the effect of a fructose-restricted diet in otherwise healthy children with abdominal pain and pathologic fructose hydrogen breath test.
Abstract Very-early-onset inflammatory bowel disease (VEO-IBD) is a heterogeneous phenotype associated with a spectrum of rare Mendelian disorders. Here, we perform whole-exome-sequencing and genome-wide genotyping in 145 patients (median age-at-diagnosis of 3.5 years), in whom no Mendelian disorders were clinically suspected. In five patients we detect a primary immunodeficiency or enteropathy, with clinical consequences ( XIAP, CYBA, SH2D1A, PCSK1 ). We also present a case study of a VEO-IBD patient with a mosaic de novo, pathogenic allele in CYBB . The mutation is present in ~70% of phagocytes and sufficient to result in defective bacterial handling but not life-threatening infections. Finally, we show that VEO-IBD patients have, on average, higher IBD polygenic risk scores than population controls (99 patients and 18,780 controls; P < 4 × 10 −10 ), and replicate this finding in an independent cohort of VEO-IBD cases and controls (117 patients and 2,603 controls; P < 5 × 10 −10 ). This discovery indicates that a polygenic component operates in VEO-IBD pathogenesis.
Improved diagnosis of coeliac disease has increased incidence and therefore burden on the health care system. There are no quality outcome measures (QOM) in use nationally to assess hospital management of this condition. This study applied QOM devised by the East of England paediatric gastroenterology network to 99 patients reviewed at two tertiary hospitals in the Network, to assess the quality of care provided by nurse led and doctor led care models. The average performance across all QOM was 96.2% at Addenbrooke’s Hospital (AH), and 98.7% at Norfolk and Norwich Hospital (NNUH), whilst 95% (n = 18) of QOM were met. Patient satisfaction was high at both sites (uptake of questionnaire 53 of 99 patients in the study). The study showed a comparably high level of care delivered by both a nurse and doctor led service. Our quality assessment tools could be applied in the future by other centres to measure standards of care.
Epigenetics can be defined as stable, potentially heritable changes in cellular phenotype caused by mechanisms other than alterations in the underlying DNA sequence. DNA methylation is amongst the most intensely studied epigenetic mechanisms and has been shown to play a major role in regulating fundamental aspects of cell biology including cellular differentiation, organ development, and cell type-specific gene expression. Importantly, it is becoming increasingly clear that epigenetic mechanisms operate at the interface between the genetic code and our environment and are able to mediate environmental changes into stable phenotypic alterations. Given existing evidence supporting the important effects of environmental factors (e.g., diet, nutrition, and infections) on human health, epigenetic mechanisms provide a plausible mechanistic framework for the development of many multifactorial diseases including inflammatory bowel disease (IBD). Impaired function of the intestinal epithelium has been implicated in IBD pathogenesis, yet underlying mechanisms remain ill defined. The work of our group focuses on investigating the role of DNA methylation in regulating cellular function of the human intestinal epithelium during gastrointestinal health and IBD. In addition to performing an analysis of primary human intestinal epithelium, we utilize human intestinal organoid culture systems allowing us to perform functional analysis in a patient-derived ex vivo model.
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