In older patients undergoing radical resection for esophageal cancer, 20 and 30 units of intranasal insulin administered for 2 days before surgery (5 times in total) also decreased POD prevalence within 3 days postoperatively (30% in the 20 unit insulin group and 3.3% in the 30 unit insulin group vs. 63.3% in the placebo group, P = 0.019 and P < 0.001, respectively) [34]. The gene discussed is INS; the disease is esophageal cancer.