title: Immunohistochemical analyses of gastric stromal tumors in Taiwanese.
abstract: OBJECTIVE
  Gastrointestinal stromal tumors (GISTs), identified by the presence of CD117 (KIT), were previously classified as gastric and intestinal smooth muscle tumors prior to the availability of immunohistochemical methods. This study evaluated the percentage of GISTs previously diagnosed as gastric smooth muscle tumors in our hospital during an 11-year period.
  
  
  METHODS
  A total of 81 surgically resected gastric smooth muscle tumor specimens from 81 patients were collected from January 1986 to December 1997. Immunohistochemical studies were performed on these tumors with antibodies of CD34, CD117, smooth muscle actin (SMA), S-100, and desmin.
  
  
  RESULTS
  Among the 81 tumors, 74 (91.4%) were CD117-positive and were classified as GISTs. Among the 74 GISTs, CD34 was positive in 72 tumors (97.3%), SMA was positive in 12 tumors (16.2%), desmin was positive in 5 tumors (6.7%), and S-100 was positive in 4 tumors (5.4%). The 7 tumors classified as non-GISTs had the following immunohistochemical characteristics: 1 was a CD117-negative CD34-positive stromal tumor (GINST) [1/81, 1.2%]; 3 were schwannomas with strong S-100-positive characteristics (3/81, 3.7%); and 3 were smooth muscle tumors with both SMA- and desmin-positive status (3/81, 3.7%). No clear relationship between CD117 or CD34 expression and prognosis was found for these tumors.
  
  
  CONCLUSIONS
  The majority (91.4%) of gastric tumors originally diagnosed as gastric smooth muscle tumors were GISTs, except for small groups of smooth muscle tumors and schwannomas.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical Center, Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
authors.forename: Tsung-Hui
authors.initials: TH
authors.lastname: Hu
authors.forename: Jui-Wei
authors.initials: JW
authors.lastname: Lin
authors.forename: Chi-Sin
authors.initials: CS
authors.lastname: Changchien
authors.forename: Shang-Yun
authors.initials: SY
authors.lastname: Liu
authors.forename: Shue-Shian
authors.initials: SS
authors.lastname: Chiou
authors.forename: Jiin-Haur
authors.initials: JH
authors.lastname: Chuang
mesh_terms: D000199:Actins / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D003893:Desmin / Q000378:metabolism; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D012189:Retrospective Studies; D009418:S100 Proteins / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism* / Q000473:pathology; D013624:Taiwan
chemical_list: D000199:Actins; D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D003893:Desmin; D009418:S100 Proteins; D019009:Proto-Oncogene Proteins c-kit