Wilms tumor (nephroblastoma) is a pediatric kidney tumor that arises from renal progenitor cells. Since the blastemal type is associated with adverse prognosis, we characterized such Wilms tumors by exome and transcriptome analysis. We detected novel, recurrent somatic mutations affecting the SIX1/2 SALL1 pathway implicated in kidney development, the DROSHA/DGCR8 microprocessor genes as well as alterations in MYCN and TP53, the latter being strongly associated with dismal outcome. The DROSHA mutations impair the RNase III domains, while DGCR8 exhibits stereotypic E518K mutations in the RNA binding domain - both may skew miRNA representation. SIX1 and SIX2 mutations affect a single hotspot (Q177R) in the homeodomain indicative of a dominant effect. In larger cohorts, these mutations cluster in blastemal and chemotherapy-induced regressive tumors that likely derive from blastemal cells and these are characterized by generally higher SIX1/2 expression. These findings broaden the spectrum of human cancer genes and may open new avenues for stratification and therapeutic leads for Wilms tumors.
Mutations in the SIX1/2 pathway and the DROSHA/DGCR8 miRNA microprocessor complex underlie high-risk blastemal type Wilms tumors.
Sex
View SamplesAtypical teratoid/rhabdoid tumor (ATRT) is one of the most common brain tumors in infants. Although the prognosis of ATRT patients is poor, some patients respond favorably to current treatments, suggesting molecular inter-tumor heterogeneity. To investigate this further, we genetically and epigenetically analyzed a large series of human ATRTs. Three distinct molecular subgroups of ATRTs, associated with differences in demographics, tumor location, and type of SMARCB1 alterations, were identified. Whole-genome DNA and RNA sequencing found no recurrent mutations in addition to SMARCB1 that would explain the differences between subgroups. Whole-genome bisulfite sequencing and H3K27Ac chromatin-immunoprecipitation sequencing of primary tumors, however, revealed clear differences, leading to the identification of subgroup-specific regulatory networks and potential therapeutic targets.
Atypical Teratoid/Rhabdoid Tumors Are Comprised of Three Epigenetic Subgroups with Distinct Enhancer Landscapes.
Sex, Age
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