title: INI1-deficient tumors: diagnostic features and molecular genetics.
abstract: Significant progress has been made in understanding the molecular genetic alterations involved in sarcomagenesis. Cytogenetic and molecular studies have identified nonrandom genetic abnormalities, including tumor suppressor gene inactivation. Mutations, deletions, and other somatic alterations in the tumor suppressor gene INI1 (hSNF5; SMARCB1), which encodes a subunit of the SWI/SNF chromatin remodeling complex, were first described in the malignant rhabdoid tumor of infancy. Since then, INI1 has also been implicated in the pathogenesis of additional tumor types including renal medullary carcinomas and epithelioid sarcomas and a subset of epithelioid malignant peripheral nerve sheath tumors, myoepithelial carcinomas, and extraskeletal myxoid chondrosarcomas. As varied as this group appears, they all show loss of INI1 protein expression, a propensity for rhabdoid cytomorphology, and sometimes other overlapping immunohistochemical and histologic findings. We will review the clinicopathologic features of these tumor types and emphasize the clinical utility of INI1 immunohistochemistry in differential diagnosis.
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Travis J
authors.initials: TJ
authors.lastname: Hollmann
authors.forename: Jason L
authors.initials: JL
authors.lastname: Hornick
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D018276:Carcinoma, Medullary / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D002813:Chondrosarcoma / Q000175:diagnosis; D002868:Chromosomal Proteins, Non-Histone / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D020732:Cytogenetic Analysis; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D009208:Myoepithelioma / Q000175:diagnosis / Q000378:metabolism; D018317:Nerve Sheath Neoplasms / Q000175:diagnosis / Q000378:metabolism; D018335:Rhabdoid Tumor / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D000071796:SMARCB1 Protein; D012509:Sarcoma / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D012983:Soft Tissue Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors