Mutational status of KIT and PDGFRA and expression of PDGFRA are not associated with prognosis after curative resection of primary gastrointestinal stromal tumors (GISTs)

J Surg Oncol. 2011 Jul 1;104(1):59-65. doi: 10.1002/jso.21905. Epub 2011 Mar 8.

Abstract

Background: The aim of this study was to investigate if immunohistochemical expression and mutational status of KIT and PDGFRA in GISTs are associated with the clinical course and disease-free survival after curative resection of the primary tumor without adjuvant systemic therapy.

Methods: Paraffin-embedded tumor sections of 95 GISTs were analyzed for KIT and PDGFRA expression by immunohistochemistry. PDGFRA expression was judged using a scoring system subdividing tumors in negative/weak and strong immunoreactivity groups. For mutation analysis, exons 9, 10, 11, 13, and 17 of KIT and exons 10, 12, 14, and 18 of PDGFRA were sequenced.

Results: Of 95 R0-resected GISTs, 69% showed strong PDGFRA immunoreactivity. Gastric GISTs revealed a significantly higher rate of strong PDGFRA immunoreactivity (P = 0.01) and longer DFS (P = 0.015) than GISTs of the small intestine. KIT mutations were detected in 43 of 63 (68.3%) completely sequenced cases while PDGFRA mutations were identified in 6 cases (10%). In multivariate analysis, neither KIT/PDGFRA expression nor mutational status of KIT or PDGFRA were independent prognostic factors. Only mitotic rate predicted recurrence independently.

Conclusion: Our data do not support the notion that expression of PDGFRA or mutations in KIT or PDGFRA are independent prognostic factors after curative resection of primary GIST.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Follow-Up Studies
  • Gastrointestinal Stromal Tumors / genetics*
  • Gastrointestinal Stromal Tumors / metabolism
  • Gastrointestinal Stromal Tumors / surgery*
  • Humans
  • Immunoenzyme Techniques
  • Male
  • Middle Aged
  • Mutation / genetics*
  • Nevus, Spindle Cell / pathology
  • Nevus, Spindle Cell / surgery
  • Prognosis
  • Prospective Studies
  • Proto-Oncogene Proteins c-kit / genetics*
  • Receptor, Platelet-Derived Growth Factor alpha / genetics*
  • Receptor, Platelet-Derived Growth Factor alpha / metabolism*
  • Survival Rate
  • Young Adult

Substances

  • Proto-Oncogene Proteins c-kit
  • Receptor, Platelet-Derived Growth Factor alpha