The results demonstrated that breast cancer patients with EGFR mutation (Student’s t-test: erlotinib, p = 0.0018; sapitinib, p = 0.0042; lapatinib, p = 0.015) and ERBB2 mutation (Student’s t-test: lapatinib, p < 2.22e-16; afatinib, p = 2.3e-2; sapitinib, p = 1.1e-3) had better sensitivity to targeted drugs (Figure 5F). This evidence concerns the gene EGFR and breast cancer.