Abstract
Atypical teratoid/rhabdoid tumors (AT/RTs) are highly aggressive brain tumors of early childhood poorly responding to therapy. The majority of cases show inactivation of SMARCB1 (INI1, hSNF5, BAF47), a core member of the adenosine triphosphate (ATP)-dependent SWI/SNF chromatin-remodeling complex. We here report the case of a supratentorial AT/RT in a 9-month-old boy, which showed retained SMARCB1 staining on immunohistochemistry and lacked genetic alterations of SMARCB1. Instead, the tumor showed loss of protein expression of another SWI/SNF chromatin-remodeling complex member, the ATPase subunit SMARCA4 (BRG1) due to a homozygous SMARCA4 mutation [c.2032C>T (p.Q678X)]. Our findings highlight the role of SMARCA4 in the pathogenesis of SMARCB1-positive AT/RT and the usefulness of antibodies directed against SMARCA4 in this diagnostic setting.
Publication types
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Case Reports
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Research Support, Non-U.S. Gov't
MeSH terms
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Brain Neoplasms / genetics
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Brain Neoplasms / pathology*
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Brain Neoplasms / therapy
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Chromosomal Proteins, Non-Histone / genetics*
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Chromosomal Proteins, Non-Histone / metabolism
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Codon, Nonsense*
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Combined Modality Therapy
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DNA Helicases / genetics*
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DNA-Binding Proteins / genetics*
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DNA-Binding Proteins / metabolism
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Fatal Outcome
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Gene Silencing
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Humans
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Infant
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Male
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Nuclear Proteins / genetics*
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Rhabdoid Tumor / genetics
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Rhabdoid Tumor / pathology*
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Rhabdoid Tumor / therapy
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SMARCB1 Protein
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Teratoma / genetics
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Teratoma / pathology*
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Teratoma / therapy
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Transcription Factors / genetics*
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Transcription Factors / metabolism
Substances
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Chromosomal Proteins, Non-Histone
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Codon, Nonsense
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DNA-Binding Proteins
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Nuclear Proteins
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SMARCB1 Protein
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SMARCB1 protein, human
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Transcription Factors
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SMARCA4 protein, human
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DNA Helicases