Beginning with the discovery that mutations in the ARID1A [69] and RHOA [70,71] genes are frequently found in subgroups of gastric cancer, a comprehensive molecular classification of gastric cancer was performed in hundreds of people, subdividing gastric cancer into four types: Epstein-Barr virus-positive, microsatellite instable, genomically stable and chromosomally instable tumors [72]. This evidence concerns the gene ARID1A and gastric cancer.