Considering the significant roles of CD8 T lymphocytes, M2 macrophages, and MMP-11, the results of the present study suggest that textural features of AGC on FDG PET/CT could reflect the degree of immune reaction in the tumor microenvironment, and AGC with increased intra-metabolic heterogeneity could be considered to have a high degree of inflammatory responses in the tumor tissue. The gene discussed is CD8A; the disease is neoplasm.