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Phosphatase and tensin homolog (PTEN) is a tumor suppressor involved in multiple cell processes. To investigate the role of PTEN in the development of gastric carcinoma, we determined the expression pattern of PTEN in primary gastric carcinoma and in paired adjacent non-neoplastic tissue. We also determined the correlation of PTEN expression with clinicopathological characteristics and patient survival. Overall, 159 gastric carcinomas and 151 paired adjacent non-neoplastic tissues were used in the present study. PTEN expression was determined using tissue microarrays and immunohistochemistry. The clinical sensitivity and specificity of PTEN expression were calculated using receiver operator characteristic curves. Results showed that the loss of cytoplasmic PTEN was significantly more frequent in carcinoma tissue compared with adjacent non-neoplastic tissue (62 vs. 5%, respectively; P<0.0001). PTEN expression was markedly downregulated in carcinoma tissues compared with adjacent non-neoplastic tissues. The loss of cytoplasmic PTEN expression was positively correlated with histological stage (P=0.016). The loss of nuclear or total PTEN, and downregulation of total PTEN expression, was significantly different between American Joint Committee on Cancer tumors of stage I and stages II-IV. A low cytoplasmic or total PTEN expression showed high clinical sensitivity and specificity for gastric carcinoma. However, PTEN expression was not significantly associated with overall or 3-year survival rates. The findings of the present study indicated that PTEN expression may be a molecular diagnostic marker for gastric cancer. Thus, the loss or reduced expression of PTEN potentially correlate with advanced stages of gastric carcinoma.

Fatty acid synthase (FAS) is the key enzyme regulating de novo biosynthesis of fatty acids. FAS overexpression has been found in many types of tumors and is associated with poor survival. However, the expression of FAS and its relationship with prognosis in Chinese patients with gastric carcinoma are still unknown. Therefore, in this study, we examined the expression of FAS using tissue microarrays and determined its correlation with clinicopathological characteristics and prognosis of gastric carcinoma in Chinese patients. FAS overexpression was graded as S (T/A) <1, ≥1 to <2, ≥2 to <3 or ≥3 in 35 (38.9%), 20 (22.2%), 9 (10%) and 26 (28.9%) patients, respectively. High FAS overexpression [S (T/A) ≥3] was significantly correlated with poor prognosis (log-rank test, P= 0.0078) and with decreased 3-year survival rate (χ(2) test, P=0.0023). FAS overexpression was not significantly associated with other clinicopathological characteristics. In conclusion, our results suggest that FAS expression might be a potential prognostic marker for gastric carcinoma in Chinese patients.