MN1 (MN1 Proto-Oncogene Transcriptional Regulator)

In our series, all three cases exhibited aggressive clinical behavior; notably, the two patients with MN1::CXXC5 gene fusion sarcomas succumbed to the disease within 20 to 23 months.

With the present report of a patient whose tumor exhibited EWSR1::BEND2 fusion, there are now 12 total reports in the literature of primary spinal AB. These cases span various pathological and molecular testing results, treatment strategies, and clinical courses. Given the diversity of current molecular signatures of spinal AB, this summative assessment of the current literature offers insights to inform guidelines for classifying AB and developing evidence-based treatment strategies going forward.

GATA2 immunostaining is highly specific for CNS tumors PATZ1-fused, but its sensitivity is perfectible and further studies are needed to confirm its use as a diagnostic tool. To conclude, our work highlights that CNS tumors, PATZ1-fused seem to represent a novel pediatric glioneuronal tumor type exhibiting a polymorphous morphology and provides new support for its addition as a provisional emerging pediatric circumscribed glioneuronal tumor type, low grade.

Collectively, our data suggest that distinct ABM-associated fusions upregulate shared transcriptional networks to disrupt the normal development of ventral telencephalon neural progenitors, which leads to oncogenic transformation. These findings uncover new avenues for targeted ABM treatment.

MN1-altered astroblastomas have an miRNA expression signature that identifies specific BPs and pathways. Our findings suggested that the involved pathways could be associated with clinical and pathological characteristics of MN1-altered astroblastomas. Also, the biology of this rare tumor could have potential implications on prognostic markers and therapy.

We validated the transcript with reverse transcription-polymerase chain reaction, Sanger sequencing, and MN1 break-apart fluorescence in situ hybridization. MN1::TAF3 was previously listed without details in a large-scale sequencing study involving a pediatric round cell sarcoma in the orbit, raising the possibility that these tumors might form a coherent group.

They typically carry a favorable prognosis. High level suspicion is required for their diagnosis and molecular analysis is must to distinguish them from other morphological mimics.

Eight of 10 patients experienced recurrence, underscoring the aggressive nature of this disease. We suggest recognizing a new molecular subgroup of spinal astroblastoma and recommend testing newly diagnosed infratentorial astroblastomas for Ewing sarcoma RNA-binding protein 1-BEND2 fusion.

MN1 expression is an independent predictor of outcome in CN-AML.

This case and others further expand the molecular findings observable in astroblastoma-like tumors outside the constraints of MN1 alteration. Such cases of astroblastoma with EWSR1::BEND2 and YAP1::BEND2 fusions challenge the current molecular classification of astroblastoma based solely on an MN1 alteration.

Interestingly, our patient developed cleft palate even without deletion of the MN1 gene, deemed responsible in previous studies. We also strongly suspect the DEPDC5 gene deletion to be responsible for seizures, consistent with previously reported cases.