APOE and colonic disorder: Moreover, EI-Bahrawy et al. suggested that APOE plays an important role in metabolism in the colon; the absence of APOE can stimulate the expression of cyclooxygenase (COX)-2 by increasing oxidized low-density lipoprotein (Ox-LDL) and tumor necrosis factor (TNF)-α, which induces inflammation and results in colon disease [74].