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Assessment of tumor suppressor promoter methylation in healthy individuals.
Poduval, Deepak B; Ognedal, Elisabet; Sichmanova, Zuzana; Valen, Eivind; Iversen, Gjertrud T; Minsaas, Laura; Lønning, Per E; Knappskog, Stian.
Afiliación
  • Poduval DB; K.G. Jebsen Center for Genome Directed Cancer Therapy, Department of Clinical Science, University of Bergen, Bergen, Norway.
  • Ognedal E; Department of Oncology, Haukeland University Hospital, Bergen, Norway.
  • Sichmanova Z; K.G. Jebsen Center for Genome Directed Cancer Therapy, Department of Clinical Science, University of Bergen, Bergen, Norway.
  • Valen E; Department of Oncology, Haukeland University Hospital, Bergen, Norway.
  • Iversen GT; Present address: Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway.
  • Minsaas L; K.G. Jebsen Center for Genome Directed Cancer Therapy, Department of Clinical Science, University of Bergen, Bergen, Norway.
  • Lønning PE; Department of Oncology, Haukeland University Hospital, Bergen, Norway.
  • Knappskog S; Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway.
Clin Epigenetics ; 12(1): 131, 2020 08 28.
Article en En | MEDLINE | ID: mdl-32859265
BACKGROUND: The number of tumor suppressor genes for which germline mutations have been linked to cancer risk is steadily increasing. However, while recent reports have linked constitutional normal tissue promoter methylation of BRCA1 and MLH1 to ovarian and colon cancer risk, the role of epigenetic alterations as cancer risk factors remains largely unknown, presenting an important area for future research. Currently, we lack fast and sensitive methods for assessment of promoter methylation status across known tumor suppressor genes. RESULTS: In this paper, we present a novel NGS-based approach assessing promoter methylation status across a large panel of defined tumor suppressor genes to base-pair resolution. The method omits the limitations related to commonly used array-approaches. Our panel includes 565 target regions covering the promoters of 283 defined tumor suppressors, selected by pre-specified criteria, and was applied for rapid targeted methylation-specific NGS. The feasibility of the method was assessed by analyzing normal tissue DNA (white blood cells, WBC) samples from 34 healthy postmenopausal women and by performing preliminary assessment of the methylation landscape of tumor suppressors in these individuals. The mean target coverage was 189.6x providing a sensitivity of 0.53%, sufficient for promoter methylation assessment of low-level methylated genes like BRCA1. Within this limited test-set, we detected 206 regions located in the promoters of 149 genes to be differentially methylated (hyper- or hypo-) at > 99% confidence level. Seven target regions in gene promoters (CIITA, RASSF1, CHN1, PDCD1LG2, GSTP1, XPA, and ZNF668) were found to be hyper-methylated in a minority of individuals, with a > 20 percent point difference in mean methylation across the region between individuals. In an exploratory hierarchical clustering analysis, we found that the individuals analyzed may be grouped into two main groups based on their WBC methylation profile across the 283 tumor suppressor gene promoters. CONCLUSIONS: Methylation-specific NGS of our tumor suppressor panel, with detailed assessment of differential methylation in healthy individuals, presents a feasible method for identification of novel epigenetic risk factors for cancer.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Regiones Promotoras Genéticas / Metilación de ADN / Proteínas Supresoras de Tumor Tipo de estudio: Prognostic_studies / Risk_factors_studies Límite: Female / Humans Idioma: En Revista: Clin Epigenetics Año: 2020 Tipo del documento: Article País de afiliación: Noruega Pais de publicación: Alemania

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Regiones Promotoras Genéticas / Metilación de ADN / Proteínas Supresoras de Tumor Tipo de estudio: Prognostic_studies / Risk_factors_studies Límite: Female / Humans Idioma: En Revista: Clin Epigenetics Año: 2020 Tipo del documento: Article País de afiliación: Noruega Pais de publicación: Alemania