SMAD7 and colorectal cancer: SMAD7 rs4939827 in the recessive and co-dominant models was associated with colorectal cancer risk [TT/CT + CC: OR = 2.90, 95%CI (1.38–6.09), p = 0.005; CC + TT/CT: OR = 1.66, 95%CI (1.00–2.75), p = 0.01].