The somatic mutation analysis between the low-risk and high-risk groups of GC patients found that the top 20 mutated genes in the two groups were TTN, TP53, MUC16, ARID1A, LRP1B, SYNE1, FLG, FAT4, CSMD3, PCLO, DNAH5, KMT2D, FAT3, HMCN1, OBSCN, RYR2, ZFHX4, SPTA1, PIK3CA, and CSMD1. The gene discussed is CSMD3; the disease is gastric cancer.