Compared with the peritoneal lavage fluid of patients with early gastric cancer and advanced gastric cancer, we detected a significant increase in the expression of CST1 in the ascites of gastric cancer patients with peritoneal metastasis, which suggested that CST1 was involved in the peritoneal metastasis of gastric cancer and was closely related to the prognosis and survival of patients. This evidence concerns the gene CST1 and gastric cancer.