Analysis Of Morphology And Mutation Of C-KIT And AKT Gene In Gastric GISTs

Background Gastrointestinal stromal tumors (GIST) is the most common gastrointestinal mesenchymal tumor, and stomach is its predilection site. More than2cm of gastric stromal tumors in diameter are easy to find and apply surgical therapy. However, the gastric stromal tumors of less than2cm are difficult to find, very little clinical pathological study about them and their biological performance is unclear. C-KIT is the driven gene of gastrointestinal stromal tumors, the morphological difference between inert small GISTs and clinic overt GISTs and whether genetic mutations of them are the same is also not unclear.ObjectiveTo study the similarities and differences of clinicopathological characteristics, Immunohistochemical staining features, c-KIT and AKT gene mutation between overt GISTs and small GISTs.MethodsCollected196cases of gastric stromal tumors from January2006to June2013in the Department of Pathology, First Affiliated Hospital of Fujian Medical University, Which are very low risk78cases, low-risk57cases, medium risk30cases, high-risk31cases. To observe clinicopathological characteristics of gastric stromal tumors, and their immunohistochemistry staining of CD117, CD34, DOG1, SMA,SDHB and so on. To detect gene mutation characteristics of AKT and c-KIT.Results1. Most of mall GIST patients are older than50. Majority of tumors are located in gastric body with low cell density. Overt GISTs are most located in up stomach1/3and low stomach1/3, younger than small GISTs, and with high cell density;2. The protein expression of CD117, CD34, DOG1and SMA have no difference between small GISTs and overt GISTs;3. Rate of SDHB defect protein in sporadic GISTs is very low (2.6%), mainly are spindle cell type;4. There are only two cases of GISTs in113with E17K point mutation of AKT gene;5. No significant difference of C-KIT gene mutation rate is found between small and overt GISTs, but they have different mutation sites, and mutation of small GISTs mainly occurred in exon11and17.Conclusions1Overt and small GISTs have the same immunophenotype, but onset of age，tumor location, and cell density are significantly different, suggesting that GISTs have distinct inert and progress behaviors;2. SDHB mutation and AKT gene mutation of GISTs are low probability events, which can be treated as special types;3. Although both overt GISTs and small GISTs have mutations in the c-KIT gene, but they have different mutation types, which may account for differences of biological behavior and set the stage for further study.