This article discusses the heterogeneity of gastric adenocarcinoma (GAC) and its impact on patient outcomes. The study used single-cell RNA sequencing and T-cell receptor sequencing to analyze tumor samples from nine GAC patients. The researchers identified different subpopulations of cells within the tumors and found that tumors with higher intratumor heterogeneity (ITH) exhibited increased copy number variation, proliferation, and hypoxia. Additionally, the study found an immunosuppressive tumor microenvironment (TME) associated with higher ITH, including the presence of M2 macrophages and exhausted T cells. The findings suggest that ITH can serve as a prognostic marker for recurrence and provide insights for immunotherapeutic strategies. However, the study had limitations in sample size and longitudinal observations, and further research is needed. [Extracted from the article]