title: SMARCB1/INI1 protein expression in round cell soft tissue sarcomas associated with chromosomal translocations involving EWS: a special reference to SMARCB1/INI1 negative variant extraskeletal myxoid chondrosarcoma.
abstract: Several previous studies have demonstrated the lack of SMARCB1/INI1 protein expression in only the malignant rhabdoid tumor (MRT). Several sarcoma groups are associated with a tumor-specific translocation involving EWS. Moreover, the EWS and SMARCB1/INI1 genes are located on the same 22q chromosome. We analyzed the status of SMARCB1/INI1 protein expression in 93 cases of sarcomas associated with chromosomal translocation involving EWS, comprising 52 Ewing's sarcoma/primitive neuroectodermal tumors, 24 extraskeletal myxoid chondrosarcomas (EMCS), 14 clear cell sarcomas of soft tissue, 2 desmoplastic small round cell tumors, and 1 myxoid/round cell liposarcoma. In addition, we analyzed the detailed SMARCB1/INI1 gene alteration in cases, which lacked its protein expression. Consequently, 4 EMCS showed no SMARCB1/INI1 expression, and 2 of these 4 cases revealed homozygous deletion and frameshift mutation of the SMARCB1/INI1 gene, respectively. These cases showed histologic findings compatible with EMCS, according to the most recent WHO classification, but no major fusion gene transcripts were detected. Moreover, 3 out of 4 SMARCB1/INI1 negative variant EMCS disclosed rhabdoid features. Therefore, the lack of SMARCB1/INI1 protein expression may be associated with rhabdoid features. The immunohistochemical result of the SMARCB1/INI expression is not an absolute diagnostic criteria for MRT and careful histologic evaluation is required to make a precise diagnosis of MRT.
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kohashi
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Sadafumi
authors.initials: S
authors.lastname: Tamiya
authors.forename: Yumi
authors.initials: Y
authors.lastname: Oshiro
authors.forename: Teiyu
authors.initials: T
authors.lastname: Izumi
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Taguchi
authors.forename: Masazumi
authors.initials: M
authors.lastname: Tsuneyoshi
mesh_terms: D002813:Chondrosarcoma / Q000737:chemistry* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis* / Q000235:genetics; D004268:DNA-Binding Proteins / Q000032:analysis* / Q000235:genetics; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D018208:Liposarcoma, Myxoid / Q000737:chemistry / Q000235:genetics; D018242:Neuroectodermal Tumors, Primitive / Q000737:chemistry / Q000235:genetics; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D011379:Prognosis; D034802:RNA-Binding Protein EWS / Q000235:genetics*; D015203:Reproducibility of Results; D018335:Rhabdoid Tumor / Q000737:chemistry* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D000071796:SMARCB1 Protein; D012509:Sarcoma / Q000737:chemistry* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D018227:Sarcoma, Clear Cell / Q000737:chemistry / Q000235:genetics; D012512:Sarcoma, Ewing / Q000737:chemistry / Q000235:genetics; D014157:Transcription Factors / Q000032:analysis* / Q000235:genetics; D014178:Translocation, Genetic
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D015514:Oncogene Proteins, Fusion; D034802:RNA-Binding Protein EWS; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors