The results indicated that the TCF7L2 rs11196172 polymorphism increases the risk of CRC independently, with no evidence of an interaction with diabetes or obesity.
Cumulative epidemiological evidence of an association was graded as strong for rs7903146 [odds ratio (OR) = 1.05, p = 4.13 × 10<sup>-5</sup> ] and rs7904519 (OR = 1.07, p = 2.02 × 10<sup>-14</sup> ) in breast cancer, rs11196172 (OR = 1.11, p = 2.22 × 10<sup>-16</sup> ), rs12241008 (OR = 1.13, p = 1.36 × 10<sup>-10</sup> ) and rs10506868 (OR = 1.10, p = 3.98 × 10<sup>-9</sup> ) in colorectal cancer, rs7086803 in lung cancer (OR = 1.30, p = 3.54 × 10<sup>-18</sup> ) and rs11196067 (OR = 1.18, p = 3.59 × 10<sup>-13</sup> ) in glioma, moderate for rs12255372 (OR = 1.12, p = 2.52 × 10<sup>-4</sup> ) in breast cancer and weak for rs7903146 (OR = 1.11, p = 0.007) in colorectal cancer.