title: Frequency, phenotype, and genotype of minute gastrointestinal stromal tumors in the stomach: an autopsy study.
abstract: Gastrointestinal stromal tumors are the most common mesenchymal tumors of the human digestive tract. Up to 85% of these tumors show somatic gain-of-function mutation of the receptor tyrosine kinase c-KIT gene. A recent study has shown a high frequency (22.5%) of minute gastrointestinal stromal tumors in stomachs examined during routine autopsies. The aims of our study were to confirm the previously reported incidence of gastric gastrointestinal stromal tumors in routine autopsies and to investigate their molecular alterations. Gastrointestinal stromal tumors were collected prospectively from 578 autopsies over an 18-month period. After recording the size and location of each lesion, representative tissue samples were processed for hematoxylin and eosin staining and immunohistochemically stained for CD117 and CD34. Microdissected DNA from all identified gastrointestinal stromal tumors was studied for c-KIT and platelet-derived growth factor receptor α mutations. We identified 17 gastrointestinal stromal tumors in 578 consecutive autopsies (2.9%) located in the gastric body (47%) and fundus (47%). One tumor location was not recorded. All tumors were immunohistochemically positive for CD117 and CD34. DNA analysis showed c-KIT mutations in 11 cases. One platelet-derived growth factor receptor α mutation was found. The incidence of gastric minute gastrointestinal stromal tumors (2.9%) is higher than the reported clinical incidence. All are benign tumors, and most, including minute tumors, contain c-KIT mutations. This finding highlights the fact that c-KIT mutations are an early event in the evolution of gastrointestinal stromal tumors but are not sufficient per se for clinically relevant disease.
authors.affiliation: Institute of Pathology, University Hospital Basel, 4031 Basel, Switzerland.
authors.forename: Simone
authors.initials: S
authors.lastname: Muenst
authors.forename: Svenja
authors.initials: S
authors.lastname: Thies
authors.forename: Philip
authors.initials: P
authors.lastname: Went
authors.forename: Luigi
authors.initials: L
authors.lastname: Tornillo
authors.forename: Michel P
authors.initials: MP
authors.lastname: Bihl
authors.forename: Stephan
authors.initials: S
authors.lastname: Dirnhofer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000032:analysis; D001344:Autopsy; D014408:Biomarkers, Tumor / Q000032:analysis; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D005838:Genotype; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D011446:Prospective Studies; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis / Q000235:genetics*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics*; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D013557:Switzerland / Q000453:epidemiology; D055815:Young Adult
chemical_list: D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha