A prospective study of the RUNX3 methylation level in all preoperative and postoperative GC patients found that the postoperative level decreased by 83% compared with the preoperative level, and that the degree of RUNX3 methylation was related to tumor stage, lymph node metastasis, and vascular invasion, with a sensitivity higher than that of carcinoembryonic antigen (CEA) (35). The gene discussed is RUNX3; the disease is gastric cancer.