Clinical, Histopathological, and Molecular Characterization of Pediatric MN1 :: ZNF341 ‐Associated Cancer

A lethal round-cell malignancy with an MN1::ZNF341 fusion has recently been reported in three infants. Here, we describe four further tumors, three in newborns (including monozygotic twins), and one in an adolescent. Detailed clinical, radiological, and histopathological data differentiate these tumors from their main mimics, neuroblastoma and round-cell sarcomas. Single-cell RNA sequencing confirms the tumor to be transcriptionally distinct from neuroblastoma, instead exhibiting steroidogenic differentiation. Whole genome and targeted DNA sequencing yield no further driver events. Our work reveals a broader clinicopathological phenotype than previously appreciated and corroborates suggestions that this tumor is a distinct and aggressive childhood cancer.