Increased expression of tyrosine phosphatase SHP-2 in Helicobacter pylori-infected gastric cancer

AIM: To explore the alteration of tyrosine phosphatase SHP-2 protein expression in gastric cancer and to assess its prognostic values. METHODS: Three hundred and five consecutive cases of gastric cancer were enrolled into this study. SHP-2 expression was carried out in 305 gastric cancer specimens, of which 83 were paired adjacent normal gastric mucus samples, using a tissue microarray immunohistochemical method. Correlations were analyzed between expression levels of SHP-2 protein and tumor parameters or clinical outcomes. Serum anti-Helicobacter pylori (H. pylori) immunoglobulin G was detected with enzyme-linked immunosorbent assay. Cox proportional hazards model was used to evaluate prognostic values by compassion of the expression levels of SHP-2 and disease-specific survivals in patients. RESULTS: SHP-2 staining was found diffuse mainly in the cytoplasm and the weak staining was also observed in the nucleus in gastric mucosa cells. Thirty-two point five percent of normal epithelial specimen and 62.6% of gastric cancer specimen were identified to stain with SHP-2 antibody positively (P < 0.001). Though SHP-2 staining intensities were stronger in the H. pylori (+) group than in the H. pylori (-) group, no statistically significant difference was found in the expression levels of SHP-2 between H. pylori (+) and H. pylori (-) gastric cancer (P = 0.40). The SHP-2 expression in gastric cancer was not significantly associated with cancer stages, lymph node metastases, and distant metastasis of the tumors (P = 0.34, P = 0.17, P = 0.52). Multivariate analysis demonstrated no correlation between SHP-2 expression and disease-free survival (P = 0.86). CONCLUSION: Increased expression of SHP-2 protein in gastric cancer specimen suggesting the aberrant up-regulation of SHP-2 protein might play an important role in the gastric carcinogenesis. (C) 2013 Baishideng. All rights reserved.