SMAD7 and colorectal carcinoma: The biological mechanisms linking CRC-associated risk variants with target genes have only been validated in the laboratory for six regions [8q24 MYC (Pomerantz et al. 2009), 8q23.3 EIF3H (Pittman et al. 2010), 11q23.1 COLCA1 and COLCA2 (Biancolella et al. 2014), 15q13.3 GREM1 (Lewis et al. 2014), 16q22.1 CDH1 (Shin et al. 2004), and 18q21.1 SMAD7 (Fortini et al. 2014)].