TCF7L2 variants are associated with: gastric, colon and rectal cancer; lung cancer; breast and prostate cancer; and renal cancer (Agalliu et al., 2008; Folsom et al., 2008; Kasper et al., 2009; Lee et al., 2016; Meyer et al., 2010; Naidu et al., 2012; Sainz et al., 2012; Torres et al., 2016; Tuupanen et al., 2009; Zhao et al., 2010). Here, TCF7L2 is linked to rectal cancer.