PIK3CA and breast neoplasm: Figure 5 intuitively reflects the high frequency of malignant neoplasm of the breast, pharmacotherapy, and trastuzumab. In addition, breast malignant tumors are associated with multiple genes, such as the phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gene, platelet-derived growth factor receptor beta (PDGFRB) gene, phosphatase and tensin homolog (PTEN) gene, and erb-B2 receptor tyrosine kinase 2 (ERBB2) gene.