Analysis of c-Kit and PDGFRa Gene Mutations in 41 Cases with Gastrointestinal Stromal tumor

[Purpose] To investigate the characteristics of c-Kit and PDGFRa gene mutations in gastrointestinal stromal tumor(GIST).[Methods] Forty-one cases of paraffin embedded GIST specimens were collected. Mutations in c-Kit exon 9,11,13,17 and PDGFRa exon 12,18 of these specimens were analyzed by direct sequencing. [Results] Of all 41 cases with GIST,34 cases showed gene mutations. Six cases contained c-Kit mutations in exon 9(14.6%),24 cases in exon11(58.5%),2 cases in exon 13(4.9%) and 2 cases contained PDGFRa mutations in exon 18(4.9%). c-Kit exon 9 mutations were exclusively observed in small intestine,while PDGFRa exon18 mutations were mainly detected in stomach. In small intestine GIST,the proportion of c-Kit exon 9 mutations accounted for 31.6%,markedly higher than that in other locations(P0.05). However,the proportion of c-Kit exon 11 mutations was 36.8%,significantly lower than that of the other locations(P0.05). [Conclusion] The types of c-Kit/PDGFRa mutations are associated with the original site of GIST. About one third patients with small intestine GIST harbor c-Kit exon 9 mutations. It is crucial to analyze c-Kit or PDGFRa gene mutation status before target therapy for these patients.