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Mutational status of KIT and PDGFRA and expression of PDGFRA are not associated with prognosis after curative resection of primary gastrointestinal stromal tumors (GISTs)
Author(s) -
Kern Alexander,
Görgens Heike,
Dittert DagDaniel,
Krüger Stefan,
Richter Konrad Klaus,
Schackert Hans K.,
Saeger HansDetlev,
Baretton Gustavo,
Pistorius Steffen
Publication year - 2011
Publication title -
journal of surgical oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.201
H-Index - 111
eISSN - 1096-9098
pISSN - 0022-4790
DOI - 10.1002/jso.21905
Subject(s) - pdgfra , gist , immunohistochemistry , medicine , exon , pathology , cancer research , stromal cell , biology , gene , genetics
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. J. Surg. Oncol. 2011;104:59–65. © 2011 Wiley‐Liss, Inc.