-509C>T polymorphism in the TGF-β1 gene promoter is not associated with susceptibility to and progression of colorectal cancer in Chinese

Aim Colorectal cancer is common, accounting for nearly 10% of all cancers. Transforming growth factor-beta 1 (TGF-beta 1) is a pleiotropic cytokine that has been implicated in the pathogenesis of colorectal neoplasia. The most studied -509C>T polymorphism of TGF-beta 1 gene has been associated with various kinds of cancer. This study investigated the association between this genetic variant and the risk and/or progression of colorectal cancer. Method A case control study was carried out of 150 colorectal cancer cases and 503 healthy controls. DNA was extracted from blood cell nuclear materials, and -509C>T polymorphism in the TGF-beta 1 gene promoter was genotyped by polymerase chain reaction restriction fragment length polymorphism (PCR-RELP). Colorectal cancer tissues (n = 70) were obtained from the studied cases for measurement of TGF-beta 1 mRNA expression levels. We also assessed the plasma TGF-beta 1 levels of cases (n = 88) and healthy subjects (n = 120). Results The TGF-beta 1 producer genotype, -509TT, was not associated with an increased risk of colorectal cancer compared with other genotypes. Colorectal cancer patients especially those with a more aggressive disease behaviour were more frequently associated with C allele. Conclusion The results suggest that TGF-beta 1 -509C>T polymorphism is not associated with either an increased risk or progression of colorectal cancer.