KEGG analysis revealed that significant genes in breast cancer were mainly involved in pathways in cancer, breast cancer, gastric cancer, melanoma, the PI3K/Akt signaling pathway, mitogen-activated protein kinase (MAPK) signaling pathway, Ras signaling pathway, tight junctions, and ubiquitin-mediated proteolysis (Figure 3). The gene discussed is PIK3CA; the disease is gastric cancer.