Further, combination therapy suppressed tumor growth and reduced expression of the Forkhead box transcription factor M1 (FOXM1) in HER2-overexpressing breast cancers resistant to trastuzumab and lapatinib, and suppressed tumor growth and increased progression free survival in patient-derived xenografts of breast, colorectal and esophageal cancers with HER2 mutations [18, 19]. This evidence concerns the gene ERBB2 and breast cancer.