The TCGA database was used to analyze the expression of 12 core genes, including COL1A1, COL1A2, COL3A1, COL5A1, BGN, COL6A3, FN1, COL11A1, COL6A2, COL4A2, GKN1, and VCAN in gastric cancer patients. The gene discussed is COL4A2; the disease is gastric cancer.