Expression of p-STAT3 in human gastric carcinoma: significant correlation in tumour invasion and prognosis.

Signal transducers and activators of transcription (STATs) belong to a family of transcription factors activated in response to cytokines and growth factors. Constitutive activation of STAT3 has been observed in a growing number of tumour-derived cell lines, as well as in tumor specimens from human cancers. Our aim was to determine the relationship between the expression of phosphorylated STAT3 (p-STAT3) and clinicopathological factors in human gastric adenocarcinoma. One-hundred and eleven cases of surgically resected human gastric adenocarcinoma were studied by immunohistochemistry. Fifty-five (49.5%) cases showed positive staining for the p-STAT3 proteins. The expression of p-STAT3 was significantly correlated with several clinicopathological factors. Moreover, expression of p-STAT3 was detected by Western blot analysis in 2 different kinds of cultured human gastric carcinoma cell lines and 4 cases of gastric carcinoma tissue obtained at surgery. Western blot analysis confirmed the presence of p-STAT3 in these specimens. In univariate survival analysis, p-STAT3 expression was associated with inferior survival (p<0.05). Constitutive activation of STAT3 may play an important role in the tumorigenesis of gastric adenocarcinoma, and the detailed mechanism of STAT3 signaling pathway in gastric adenocarcinoma deserves further investigation.