PDCD1 and hyperinsulinemic hypoglycemia, familial, 4: Researches have indicated that programmed cell death 1 (PD-1) monoclonal antibodies, pembrolizumab and nivolumab, are effective in treating metastatic colon cancer in patients who exhibit mismatch-repair deficiency (dMMR) and high microsatellite instability (MSI-H) [4, 5].