To investigate the GC mutation profile and determine its prognostic value, we conducted a study of 77 GC tumour samples using next-generation sequencing (NGS) on both the Ion AmpliSeq Cancer Hotspot Panel v2, covering mutation hotspots in 50 cancer-related genes, and a custom panel covering six hereditary gastric cancer predisposition genes (BMPR1A, SMAD4, CDH1, TP53, STK11 and PTEN). The gene discussed is SMAD4; the disease is gastric cancer.