ERBB2 and cancer: Supported by the RPPA results and the image-based screen results indicating that the HER2 expression was amplified in a dose-dependent manner by lapatinib and downregulated by the EGFR-TKis (Figure 4B and Supplementary Figure S5A), we rationalized that combination of lapatinib could potentiate the overall therapeutic efficacy of the EGFR-TKis as reported in several human cancers (23–25).