In this study, we utilized MSS mouse gastric cancer MTC cells (Trp53−/−; Cdh1−/−), MSS gastric cancer in vivo models (MycOE; Trp53−/−), and human MSS/MSI-low cell lines (SNU668, MKN28) for immunological and mechanistic investigations. Here, CDH1 is linked to medullary thyroid gland carcinoma.