Application of immunohistochemistry to the diagnosis of gastrointestinal stromal tumors of 64 cases

Purpose To investigate the ability of immunohistochemical markers for the diagnosis and differential diagnosis of gastrointestinal stromal tumors(GISTs).Methods 85 cases of diagnosed gastrointestinal,pelvic or abdominal mesenchymal tumors were collected,including 64 gastrointestinal stromal tumors,and subjected to immunohistochemistry with antibodies to CD117,CD34,DOG1,NSE,S-100,SMA and vimentin.Results The staining results showed that in GISTs,the positive rates of CD117,CD34,DOG1 and NSE were 89.1%,76.6%,96.9% and 87.5% respectively.In non-GISTs,the positive rates of CD117,CD34,DOG1 and NSE were 4.8%,33.3%,28.6% and 50.0% respectively.In CD117-negative GISTs,the positive rates of CD34,NSE and DOG1 were 28.6%,71.4% and 85.7%.Conclusions The expression of DOG1 in gastrointestinal stromal tumors is more sensitive than CD117 and other immunomarkers especially in CD117-negative GISTs.In most cases of suspected GISTs a combination of CD117,DOG1 and NSE immunostaining should be sufficient to confirm the diagnosis.