Abstract
Background and objective
to analyze the frequency and spectrum of KIT and plateletโderived growth factor receptorโalpha (PDGFRA) gene in a large series of study and to explore the clinical implication of mutations in the gastrointestinal stromal tumors (GISTs) in China.
Method
A total of 141 GISTs were subject to mutation analysis of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) using PCR amplification and direct sequencing. Clinicopathologic characteristics were correlated to gene mutations.
Results
Of the 141 tumors studied, approximately 76.6% had KIT gene mutations, 2.8% had PDGFRA gene mutations and 20.6% had a wildโtype gene of KIT and PDGFRA. Among those with KIT gene mutations, 70.2% occurred in exon 11, 5.7% in exon 9, 0.7% in exon 13, and no mutation was detected in exons 17. The most frequent sites of mutation were in exon 11 and the mutations clustered in the classic โhot spotโ at the 5โฒend of the exon mostly heterogeneous and the second โhot spotโ were internal tandem duplications (ITD) at the 3โฒend of the exon. The overall mutation rate was significantly lower in GISTs originated from colorectum or extraโgastrointestinal tract (ฯ^2^โ=โ6.728, Pโ=โ0.009; ฯ^2^โ=โ4.059, Pโ=โ0.044), however, mutation rate on exon 11 was significantly increased in gastric stromal tumor (ฯ^2^โ=โ5.713, Pโ=โ0.017; ฯ^2^โ=โ4.341, Pโ=โ0.037). There were no significant differences in terms of age, gender, tumor size, mitotic counts, grade of malignant potential and liver metastasis in patients with or without gene mutations.
Conclusion
KIT and PDGFRA gene were frequently found in patients with GISTs. Gene mutation rate varies in originated organ. J. Surg. Oncol. 2008;98:175โ178. ยฉ 2008 WileyโLiss, Inc.