OBJECTIVE: This study aimed to examine the relationship between expression of 
mammal target of rapamycin (mTOR) and phosphorylation of mTOR (p-mTOR) protein 
in the PI3K/Akt/mTOR signaling pathways in gastrointestinal stromal tumors and 
relatiuonships with clinical factors.
METHODS: Immunohistochemistry was used to detect the expression of the 
associated proteins mTOR, p-mTOR, and phosphorylation of the tumor suppressor 
genes PTEN, P27, VEGF, and EGFR in 40 cases of gastrointestinal stromal tumors, 
with division into a very low and low risk group as well as a moderate and high 
risk group.
RESULTS: The positive rate of mTOR and p-mTOR was significantly increased in the 
moderate and high risk group compared with the very low and low risk group. The 
difference was statistically significant (P<0.05). When grouped according to 
size, the positive mTOR expression rate exhibited a statistical difference 
(P<0.05), which was significantly increased in the group of tumors larger than 5 
cm. The difference in the positive mTOR and p-mTOR expression rate exhibit no 
statistical significance among the PTEN, P27, VEGF, and EGFR expression 
subgroups (P>0.05).
CONCLUSION: The different expressions of mTOR and p-mTOR in the signal 
transduction pathway of gastrointestinal stromal tumor in the different 
degree-of-risk groups suggested that the mTOR and p-mTOR of the signal 
transduction pathway serve an important function in the occurrence and 
development of gastrointestinal stromal tumors.