title: Absence of expression of SMARCB1/INI1 in malignant rhabdoid tumors of the central nervous system, kidneys and soft tissue: an immunohistochemical study with implications for diagnosis.
abstract: Malignant rhabdoid tumors are high-grade neoplasms of the central nervous system (CNS), kidneys and soft tissue that usually occur in children. The histologic diagnosis of malignant rhabdoid tumor depends on identification of characteristic rhabdoid cells-large cells with eccentrically located nuclei and abundant, eosinophilic cytoplasm-and immunohistochemistry with antibodies to vimentin, keratin and epithelial membrane antigen. In most malignant rhabdoid tumors, the SMARCB1/INI1 gene, located in chromosome band 22q11.2, is inactivated by deletions and/or mutations, so genetic diagnosis is often possible. However, tissue may not be available for genetic analysis or studies not confirmatory. We assessed SMARCB1/INI1 expression in 17 rhabdoid tumors and 57 other tumors of the CNS, kidney or soft tissue using immunohistochemistry. In total, 12 brain, three renal and two soft tissue rhabdoid tumors were examined along with four glioblastomas, four pilocytic astrocytomas, four oligodendrogliomas, two ependymomas, two choroid plexus papillomas, five pituitary adenomas, four germinomas, four renal carcinomas with Xp11.2 translocations, two clear cell sarcomas, two Wilms' tumors, one renal medullary carcinoma, two desmoplastic small round cell tumors, two alveolar rhabdomyosarcomas, two embryonal rhabdomyosarcomas, one low-grade chondrosarcoma, two extraskeletal myxoid chondrosarcomas, one mesenchymal chondrosarcoma, four malignant peripheral nerve sheath tumors, five metastatic carcinomas and four epithelioid sarcomas, two primary and two metastatic. The neoplastic cells of all rhabdoid tumors, the four epithelioid sarcomas and the renal medullary carcinoma did not express SMARCB1/INI1 by immunohistochemistry; neoplastic cells of all other tumors expressed SMARCB1/INI1. Immunohistochemistry to assess expression of SMARCB1/INI1 may be useful in the diagnosis of rhabdoid tumors of the CNS, kidneys and soft tissue.
authors.affiliation: Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9073, USA.
authors.forename: Ellen
authors.initials: E
authors.lastname: Sigauke
authors.forename: Dinesh
authors.initials: D
authors.lastname: Rakheja
authors.forename: Debra L
authors.initials: DL
authors.lastname: Maddox
authors.forename: Christa L
authors.initials: CL
authors.lastname: Hladik
authors.forename: Charles L
authors.initials: CL
authors.lastname: White
authors.forename: Charles F
authors.initials: CF
authors.lastname: Timmons
authors.forename: Jack
authors.initials: J
authors.lastname: Raisanen
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology; D016543:Central Nervous System Neoplasms / Q000378:metabolism / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D007680:Kidney Neoplasms / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D018335:Rhabdoid Tumor / Q000378:metabolism / Q000473:pathology*; D000071796:SMARCB1 Protein; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology*; D014157:Transcription Factors / Q000096:biosynthesis*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors