An updated meta-analysis on the association of TGF-β1 gene promoter -509C/T polymorphism with colorectal cancer risk

► TGF-β1-509C/T variant might affect the susceptibility of colorectal cancer. ► An increased CRC risk was found in subjects with TGF-β1-509CC + CT totally. ► TGF-β1 C allele variant increased the risk of CRC in population-based study. ► TGF-β1 C allele variant increased the CRC risk in European and American population. ► TGF-β1 CC + CT genotype was associated with an increased risk of colon cancer.