REG4 and colorectal cancer: Oue et al. (2007) found that the preoperative serum REG4 concentration was not elevated in patients with colorectal cancer at stages 0–III, but was significantly elevated in those at stage IV. Additionally, REG4 expression, as an independent predictor, was significantly linked to a worse prognosis in patients with colorectal cancer (Oue et al., 2007; Numata et al., 2011; He et al., 2014). However, Kaprio et al. (2014) reported that REG4 expression was an independent marker of a lower risk of death for patients with non-mucinous colorectal cancer, 65 years and younger, within 5 years.