Figure 3. Screening of differentially expressed genes based on protein-protein interaction (PPI) and Univariate Cox regression analysis. (A) PPI network of the aberrantly expressed genes based on STRING (interaction confidence value > 0.95). (B) Visualized PPI analysis of differentially expressed genes using Cytoscape. (C) Top 30 genes with maximum adjacent nodes. (D) Univariate Cox regression analysis for the aberrantly expressed genes. Genes with a p value less than 0.05 are shown in the forest plot. (E) Venn diagram of key genes in PPI and Cox regression analysis. Four TIIC-related genes (CCR2, CCR4, P2RY12, and P2RY13) were finally screened as prognostic factors of LUAD.