Figure 2 Construction of the protein-protein interaction (PPI) network complex with the STRING database and acquisition of 3 significant modules on the basis of the topological structure of the PPI network of the common uDEGs and dDEGs. (A) PPI network of uDEGs and dDEGs in LUAD tissues compared with corresponding normal adjacent tissues; (B) module 1, cluster score=25.407, 28 nodes and 343 edges; (C) module 2, cluster score=8.741, 28 nodes and 118 edges; (D) module 3, cluster score=5, 5 nodes and 10 edges. The blue squares indicate a node degree less than 30. uDEGs – upregulated differentially expressed genes; dDEGs – downregulated differentially expressed genes; LUAD – lung adenocarcinoma.