The 5-year overall survival rates of patients with or without PIK3CA amplifications were not significantly different (54.4% vs. 57.1%, P=0.102), and those of the two groups with either early gastric cancer (85.4% vs. 91.3%, P=0.662) or advanced gastric cancer were also not significantly different (47.3% vs. 51.5%, P=0.055). This evidence concerns the gene PIK3CA and gastric cancer.