In human colon cancer cells, activation of p53 upregulates Fas on the surface of MDSCs, which increases the sensitivity of MDSCs to FasL-induced cell apoptosis, that is, by activating the intrinsic p53–Fas–FasL pathway of MDSCs, promotes cell apoptosis, and reactivates CTL-mediated antitumor immunity [62]. The gene discussed is FAS; the disease is malignant colon neoplasm.