Abstract:

Objective To investigate expressions of discovered on GIST-1（DOG1），CD117 and insulin-like growth factor 1 receptor（IGF1R），and the mutation status of c-KIT and PDGFRA gene in gastrointestinal stromal tumors （GISTs），as well as the relations between them and clinicopathologic features of GISTs.Methods The expressions of DOG1，CD117 and IGF1R were detected by immunohistochemistry in 98 GISTs and 40 non-GISTs. Mutations of c-KIT and PDGFRA were analyzed using a matrixassisted laser desorption／ionizationtime of flight（MALDI-TOF）mass spectrometer.Results The positive expression rates of DOG1，CD117 and IGF1R in GISTs were 92.9％，95.9％ and 6.1％，respectively. And in non-GISTs，the positive rates of DOG1 and CD117 were 10.0％ and 17.5％，lower than those in GISTs（P＜0.001）. The expression of DOG1 was correlated with tumor size and risk degree. For CD117，its expression was related to tumor location and histological types. IGF1R was not significantly associated with clinicopathologic features. Of 77 GISTs，mutation rates of c-KIT and PDGFRA were 64.9％ and 22.1％，and the most common mutational sites were exon 11（54.0%）and 12（16.9%）respectively. The mutation rates of PDGFRA and c-KIT were only related to tumor location（P=0.001，P=0.002）. Expressions of CD117 and DOG1 were not related to mutations of c-KIT or PDGFRA gene. But IGF1R's expression was significantly different between wild-type and mutated GISTs.Conclusion Detection of both DOG1 and CD117 can raise the diagnostic rate of GISTs，especially for those who has negative expression of CD117 and the results can help analyze clinicopathologic features of GISTs comprehensively. Our results suggest that IGF1R is a special marker and potential the rapeutic target for wild-type GISTs. There will be more useful to analyze response to tyrosine kinase inhibitors and prognosis of GISTs with gene mutation analysis and tumor locations.