Tumor protein p53 (TP53) (OMIM 191170), phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha (PIK3CA) (OMIM 171834), AT-Rich Interaction Domain 1A (ARID1A) (OMIM 603024), ataxia-telangiectasia mutated (ATM) (OMIM 607585), and Lysine Methyltransferase 2D (KMT2D) (OMIM 602113) were identified to possess higher stress and more edgecounts than other genes, which implied their central position and complex interactions in the PPI network of BC. This evidence concerns the gene PIK3CA and breast cancer.