title: Gastrointestinal stromal tumor: evidence for a smooth-muscle origin.
abstract: A gastrointestinal stromal tumor, arising from the rectal ampulla of a 63-yr-old man, was investigated using conventional techniques as well as Western blot analysis of its cytoskeleton proteins. The expression of desmin, muscle-specific actins, vimentin, S-100 protein, chromogranin, neuron-specific enolase, and keratins was studied using the avidin-biotin technique. The tumor cells showed a positive reaction only to antivimentin antibody. Ultrastructural analysis failed to provide conclusive evidence for neural or muscular origin of the tumor. Western blot analysis of the tumor whole-protein extract allowed identification of the presence of gamma-smooth-muscle actin, thus suggesting an enteric smooth-muscle origin of the tumor. This result seems partially to support a parenchymal smooth-muscle origin for S-100 protein and desmin-negative gastrointestinal tumors.
authors.affiliation: Department of Surgery, Università di Roma Tor Vergata, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Tirabosco
authors.forename: A O
authors.initials: AO
authors.lastname: Cavazzana
authors.forename: G
authors.initials: G
authors.lastname: Santeusanio
authors.forename: L G
authors.initials: LG
authors.lastname: Spagnoli
mesh_terms: D000199:Actins / Q000032:analysis; D000368:Aged; D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000032:analysis*; D005770:Gastrointestinal Neoplasms / Q000737:chemistry / Q000175:diagnosis / Q000648:ultrastructure*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008854:Microscopy, Electron; D018235:Smooth Muscle Tumor / Q000737:chemistry / Q000175:diagnosis / Q000648:ultrastructure*
chemical_list: D000199:Actins; D003598:Cytoskeletal Proteins