title: Gastrointestinal stromal tumors and KIT-positive mesenchymal cells in the omentum.
abstract: Gastrointestinal stromal tumor (GIST) is currently considered to be derived from the interstitial cells of Cajal (ICC). To test the hypothesis that omental mesenchymal tumor is also a type of GIST, we evaluated the expression of specific molecules in GIST, and c-kit gene mutation in omental mesenchymal tumors, and we identified a possible counterpart of ICC in the omentum. Immunohistochemically, all of the omental mesenchymal tumors (n = 5) were positive for both KIT and CD34, and three of the five tumors were also positive for an embryonic form of smooth-muscle myosin heavy chain (SMemb). Polymerase chain reaction-single-strand conformational polymorphism analysis (PCR-SSCP) and direct sequencing revealed mutations in c-kit gene exon 11 in all five tumors. As for the ICC counterparts in the omentum, there were some KIT-positive mesenchymal cells resembling ICC at the surface of the omentum. Double fluorescence immunostaining, using anti-KIT polyclonal antibodies and monoclonal antibodies against other molecules, demonstrated that KIT-, CD34- and SMemb-positive cells were present just beneath the mesothelial cells of the omentum. These results show that omental mesenchymal tumor corresponds to GIST of the omentum, and that KIT-positive bipolar mesenchymal cells may be a counterpart of ICC in the gastrointestinal tract. Identification of a new type of KIT-positive mesenchymal cell in the omentum may lead to the discovery of a new physiological role for this organ.
authors.affiliation: Department of Pathology, Jichi Medical School, Tochigi, Japan. ssakurai@jichi.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Sakurai
authors.forename: T
authors.initials: T
authors.lastname: Hishima
authors.forename: Y
authors.initials: Y
authors.lastname: Takazawa
authors.forename: T
authors.initials: T
authors.lastname: Sano
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: K
authors.initials: K
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Morinaga
authors.forename: M
authors.initials: M
authors.lastname: Fukayama
mesh_terms: D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000032:analysis; D004252:DNA Mutational Analysis; D017931:DNA Primers / Q000737:chemistry; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D008969:Molecular Sequence Data; D009197:Myenteric Plexus / Q000473:pathology; D009852:Omentum / Q000378:metabolism* / Q000473:pathology; D010534:Peritoneal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism*; D017154:Stromal Cells / Q000378:metabolism / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D017931:DNA Primers; D004273:DNA, Neoplasm; D019009:Proto-Oncogene Proteins c-kit