Roles of Transforming Growth Factor-β1, Smad3, Smad4 and Smad7 in the Development of Colorectal Cancer

Background: Colorectal adenoma-adenocarcinoma sequence is the accepted hypothesis of tumorigenesis of colorectal cancer. However, clinical studies about the expression of transforming growth factor (TGF)-β1 pathway protein in colorectal adenoma, especially in high risk colorectal adenoma are rare. Aims: To explore the roles of TGF-β1, Smad3, Smad4 and Smad7 in the development of colorectal cancer. Methods: One hundred and ten cases of colorectal polyps (including adenomatous polyp and non-adenomatous polyp), 40 colorectal cancer and 20 normal colorectal tissues in Liu’an People’s Hospital from Aug. 2000 to Dec. 2006 were enrolled. Expression of TGF-β1, Smad3, Smad4 and Smad7 were detected by immunohistochemistry. The relationship between expression of TGF-β1, Smad3, Smad4 and Smad7 and clinicopathologic features in high risk adenoma was analyzed. Results: Statistical differences in expression of TGF-β1, Smad3, Smad4 and Smad7 were found in polyps group, colorectal cancer group and control group (P0.05). No significant relationship was found between clinicopathologic features in high risk adenoma and expression of TGF-β1, Smad3, Smad4 and Smad7. Expression of TGF-β1, Smad3 and Smad7 in high risk adenoma was significantly higher than those in colorectal cancer of Dukes A stage (P0.05), but not Smad4. Conclusions: TGF-β1 pathway may be involved in the tumorigenesis of colorectal cancer, and expression of TGF-β1, Smad3 and Smad7 may play some roles in the early stage of carcinogenesis of colorectal adenoma.