Project description:Molecular characteristics of pediatric brain tumors have not only allowed for tumor subgrouping but have introduced novel treatment options for patients with specific tumor alterations. Therefore, an accurate histologic and molecular diagnosis is critical for optimized management of all pediatric patients with brain tumors, including central nervous system embryonal tumors. We present a case where optical genome mapping identified a ZNF532-NUTM1 fusion in a patient with a unique tumor best characterized histologically as a central nervous system embryonal tumor with rhabdoid features. Additional analyses including immunohistochemistry for NUT protein, methylation array, whole genome, and RNA-sequencing was done to confirm the presence of the fusion in the tumor. This is the first description of a pediatric patient with a ZNF532-NUTM1 fusion, yet the histology of this tumor is similar to that of adult cancers with ZNF-NUTM1 fusions and other NUTM1-fusion positive brain tumors reported in literature. Although rare, the distinct pathology and underlying molecular characteristics of these tumors separate them from other embryonal tumors. Therefore, the NUTM-rearrangement appears to define a novel subgroup of pediatric central nervous system embryonal tumors with rhabdoid/epithelioid features that may have a unique response to treatment. Screening for a NUTM1-rearrangement should be considered for all patients with unclassified central nervous system tumors with rhabdoid features to ensure accurate diagnosis so this can ultimately inform therapeutic management for these patients.
Project description:Molecular characteristics of pediatric brain tumors have not only allowed for tumor subgrouping but have introduced novel treatment options for patients with specific tumor alterations. Therefore, an accurate histologic and molecular diagnosis is critical for optimized management of all pediatric patients with brain tumors, including central nervous system embryonal tumors. We present a case where optical genome mapping identified a ZNF532-NUTM1 fusion in a patient with a unique tumor best characterized histologically as a central nervous system embryonal tumor with rhabdoid features. Additional analyses including immunohistochemistry for NUT protein, methylation array, whole genome, and RNA-sequencing was done to confirm the presence of the fusion in the tumor. This is the first description of a pediatric patient with a ZNF532-NUTM1 fusion, yet the histology of this tumor is similar to that of adult cancers with ZNF-NUTM1 fusions and other NUTM1-fusion positive brain tumors reported in literature. Although rare, the distinct pathology and underlying molecular characteristics of these tumors separate them from other embryonal tumors. Therefore, the NUTM-rearrangement appears to define a novel subgroup of pediatric central nervous system embryonal tumors with rhabdoid/epithelioid features that may have a unique response to treatment. Screening for a NUTM1-rearrangement should be considered for all patients with unclassified central nervous system tumors with rhabdoid features to ensure accurate diagnosis so this can ultimately inform therapeutic management for these patients.
Project description:NUT carcinoma (NC) is an aggressive cancer with no effective treatment. About 70% of NUT carcinoma is associated with chromosome translocation events that lead to the formation of a BRD4::NUTM1 fusion gene. Because the BRD4::NUTM1 gene is unequivocally cytotoxic when ectopically expressed in cell lines, questions remain on whether the fusion gene can initiate NC. Here, we report the first genetically engineered mouse model (GEMM) for NUT carcinoma that recapitulates the t(15;19) chromosome translocation in mice. We demonstrated that the mouse t(2;17) syntenic chromosome translocation, forming the Brd4::Nutm1 fusion gene, could induce aggressive carcinomas in mice. The tumors present histopathological and molecular features similar to human NC, with an enrichment of undifferentiated cells. Similar to the reports of human NC incidence, Brd4::Nutm1 can induce NC from a broad range of tissues with a strong phenotypical variability. The consistent induction of poorly differentiated carcinoma demonstrated a strong reprogramming activity of BRD4::NUTM1. The new mouse model provided a critical preclinical model for NC that will lead to better understanding and therapy development for NC.
Project description:NUT carcinoma (NC) is an aggressive cancer with no effective treatment. About 70% of NUT carcinoma is associated with chromosome translocation events that lead to the formation of a BRD4::NUTM1 fusion gene. Because the BRD4::NUTM1 gene is unequivocally cytotoxic when ectopically expressed in cell lines, questions remain on whether the fusion gene can initiate NC. Here, we report the first genetically engineered mouse model (GEMM) for NUT carcinoma that recapitulates the t(15;19) chromosome translocation in mice. We demonstrated that the mouse t(2;17) syntenic chromosome translocation, forming the Brd4::Nutm1 fusion gene, could induce aggressive carcinomas in mice. The tumors present histopathological and molecular features similar to human NC, with an enrichment of undifferentiated cells. Similar to the reports of human NC incidence, Brd4::Nutm1 can induce NC from a broad range of tissues with a strong phenotypical variability. The consistent induction of poorly differentiated carcinoma demonstrated a strong reprogramming activity of BRD4::NUTM1. The new mouse model provided a critical preclinical model for NC that will lead to better understanding and therapy development for NC.
Project description:NUT carcinoma (NC) with mesenchymal differentiation have rarely been described in the literature. In this report, we describe the characterization of two cases of high grade spindle cell sarcoma harboring a novel MGA-NUTM1 fusion. Whole genome sequencing identified the presence of complex rearrangements resulting in a MGA-NUTM1 fusion gene in the absence of other significant somatic mutations. The fusion protein was predicted to retain nearly the entire protein sequence of both MGA (exons 1-22) and NUTM1 (exons 3-8). In contrast to typical cases of NC, these cases were successfully treated with aggressive local control measures (surgery and radiation) and both patients remain alive without disease. These cases describe a new subtype of NUTM1-rearranged tumors warranting expansion of diagnostic testing to evaluate for the presence of MGA-NUTM1 or alternative NUTM1 gene fusions in the diagnostic workup of high grade spindle cell sarcomas or small round blue cell tumors of ambiguous lineage.
Project description:The identification of subtype-specific translocations has revolutionized diagnostics of sarcoma and provided new insight into oncogenesis. We used RNA-Seq to investigate samples diagnosed as small round cell tumors of bone, possibly Ewing sarcoma, but lacking the canonical EWSR1-ETS translocation. A new fusion was observed between the BCL6 co-repressor (BCOR) and the testis specific cyclin B3 (CCNB3) genes on chromosome X. RNA-Seq results were confirmed by RT-PCR and cloning the tumor-specific genomic translocation breakpoints. 24 BCOR-CCNB3-positive tumors were identified among a series of 594 sarcomas. Gene profiling experiments indicate that BCOR-CCNB3-positive cases are biologically distinct from other sarcomas, particularly EwingM-bM-^@M-^Ys sarcoma. Finally, we show that CCNB3 immunohistochemistry is a powerful diagnostic marker for this group of sarcoma and that over-expression of BCOR-CCNB3 or of a truncated CCNB3 activates S-phase in NIH3T3 cells. Thus the intrachromosomal X fusion described here represents a new subtype of bone sarcoma caused by a novel gene fusion mechanism. Comparison of expression profiles of 10 BCOR-CCNB3 samples (plus 4 EWS-FLI1 Ewing sarcomas samples as control) with publicly available profiles of other tumor types.
Project description:Pediatric embryonal brain tumor (PEBT), which includes medulloblastoma (MB), primitive neuroectodermal tumor (PNET) and atypical teratoid/rhabdoid tumor (AT/RT), is the second most prevalent pediatric tumor type among brain tumors of childhood. AT/RT is highly malignant and is often misdiagnosed as MB and PNET. Distinguishing AT/RT from PNET/MB is of clinical significance since the survival rate of AT/RT patients is much lower. The diagnosis of AT/RT relies primarily on the morphologic assessment and immunohistochemistry (IHC) staining on a few known markers such as the lack of INI1 protein expression. However, in our clinical practice we observed several AT/RT-like tumors, which fulfilled histopathologic and all other biomarker criteria for AT/RT diagnosis, still showed retained INI1 immunoreactivity. Recent studies also reported retained INI1 immunoreactivity among certain diagnosed AT/RTs. It is therefore necessary to re-evaluate INI1(+), AT/RT-like cases. Sanger sequencing, array CGH and mRNA microarray analyses were performed on PEBT samples for studying their genomics landscapes. AT/RT and INI(+) AT/RT-like patients had similar survival rate, and global array CGH analysis and INI1 gene sequencing showed there is no differential chromosomal aberration marker between INI1(-) AT/RT and INI(+) AT/RT-like cases. We did not misdiagnose MB or PNET as AT/RT-like cases since transcriptome profiling revealed that not only AT/RT and INI(+) AT/RT-like cases expressed distinct mRNA and microRNA profiles, and their gene expression patterns were different from those of MBs and PNETs. AT/RTs shared the closest transcriptome profile to embryonic stem cells, INI1(+) AT/RT-like tumors were more similar to somatic neural stem cell, while MBs were closer to fetal brain. Novel biomarkers were identified to distinguish INI1(-) AT/RTs, INI1(+) AT/RT-like cases and MBs. Our studies disclosed a novel INI1(+) ATRT-like subtype among Taiwanese pediatric cases. New diagnostic biomarkers, as well as new therapeutic tactics, can be developed according to the transcriptome information unveiled in this work. 2 AT/RT-like cases and 7 AT/RT cases are subjected to transcriptome analysis.