Integrated molecular characterization of the lethal pediatric cancer pancreatoblastoma

Pancreatoblastoma (PBL) is a rare pediatric pancreatic malignancy for which the molecular pathogenesis is not understood. In this study, we report the findings of an integrated multi-omics study of whole exome and RNA sequencing as well as genome-wide copy number and methylation analyses of 10 PBL cases. The PBL genome was characterized by a high frequency of aberrant activation of the Wnt signaling pathway, either via somatic mutations of CTNNB1 (90%) and copy-neutral loss of heterozygosity (CN-LOH) of APC (10%). In addition, imprinting dysregulation of IGF2 as a consequence of CN-LOH (80%), gain of paternal allele (10%), and gain of methylation (10%) were universally detected. At the transcriptome level, PBL exhibited an expression profile characteristic of early pancreas progenitor-like cells along with upregulation of the R-spondin/LGR5/RNF43 module. Our results offer a comprehensive description of the molecular basis for PBL and highlight rational therapeutic targets for its treatment.

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