Given that the 3 key genes and macrophage abundance were independent prognostic factors for STAD, we performed GSEA to determine the shared KEGG pathways and Hallmarks between low macrophage abundance/LUM/ABCA8/SHC4 groups and high macrophage abundance/LUM/ABCA8/SHC4 groups in the TCGA-GSE84433 joint cohort. Here, ABCA8 is linked to gastric adenocarcinoma.