Abstract: Objective To study expressions of phosphatase and tensin homologue deleted on chromosome 10 (PTEN),phosphorylated protein kinase B (p-AKT),and phosphorylated mammalian target of rapamycin (p-mTOR)in gastric cancer tissues and their relevance with clinicopathological features of gastric cancer.Methods Immunohistochemistry technology was used to detect expressions of PTEN,p-AKT and p-mTOR in gastric carcinoma tissues,tumor-adjacent tissues and normal gastric mucous tissues and their relationships with pathological parameters were analyzed.Results The PTEN level in gastric carcinoma tissues was significantly lower than that in tumor-adjacent and normal gastric mucous tissues;while the levels of p-AKT and p-mTOR were significantly higher than those in tumor-adjacent and normal gastric mucous tissues (P<0.05 for all).The expression of PTEN was irrelevant to clinicopathological features.The expression of p-AKT was associated with the differentiation degree of tumors,infiltration depth,lymph node metastasis and tumor-node-metastasis(TNM) staging (all P<0.05);however,there were no relationships with age,gender and tumor sizes (P>0.05 for all).The expression of p-mTOR in gastric carcinoma tissues showed no relationship with the clinical histopathological features but the depth of invasion.The expression of PTEN was negatively correlated to the p-AKT expression (P<0.05);but there was no significant correlation between p-mTOR protein and PTEN protein and p-AKT protein expression (both P>0.05).Conclusion The PTEN expression is down-regulated and the expression of p-AKT and p-mTOR are up-regulated in gastric cancer tissues,suggesting that PI3K/AKT/mTOR signaling pathway may be involved in the occurrence and development of gastric cancer.