Constitutive activation of Stat3 signaling pathway in human colorectal carcinoma

World J Gastroenterol. 2004 Jun 1;10(11):1569-73. doi: 10.3748/wjg.v10.i11.1569.


Aim: Signal transducers and activators of transcription (STATs) are 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 tumor-derived cell lines, as well as tumor specimens from human cancers. The purpose of this study was to investigate the expression of p-Stat3, activated form of Stat3, and its downstream mediators including cyclin D1 and Bcl-x(L) in colorectal carcinoma (CRC), and to explore the possible mechanism of Stat3 signaling pathway in the tumorigenesis of colorectal carcinoma.

Methods: Tissue samples from 45 patients of primary colorectal carcinoma were selected for studying Stat3 signaling pathway protein expression. Western blot analysis was used to measure the expression of p-Stat3, cyclin D1, and Bcl-x(L) proteins in colorectal carcinomas. Furthermore, the expression patterns of these proteins were analyzed for their distribution at the cellular level by immunohistochemical staining of the tissues.

Results: Protein levels of p-Stat3, cyclin D1, and Bcl-x(L) were increased in colorectal carcinomas compared with adjacent normal mucosae (P<0.05). Elevated levels of p-Stat3 were correlated with the nodal metastasis and the stage (P<0.05). Overexpression of cyclin D1 was associated with the nodal metastasis (P<0.05). There was also a significant correlation between the expressions of p-Stat3 and cyclin D1 (r=0.382, P<0.05).

Conclusion: Constitutive activation of Stat3 may play an important role in the tumorigenesis of colorectal carcinoma, and the detailed mechanism of Stat3 signaling pathway in CRC deserves further investigation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / metabolism*
  • Adenocarcinoma / pathology
  • Adult
  • Aged
  • Aged, 80 and over
  • Colorectal Neoplasms / metabolism*
  • Colorectal Neoplasms / pathology
  • DNA-Binding Proteins / metabolism*
  • Female
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • STAT3 Transcription Factor
  • Signal Transduction / physiology*
  • Trans-Activators / metabolism*


  • DNA-Binding Proteins
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Trans-Activators