ERBB2 and neoplasm: Studies in vitro and in vivo using xenografted mice with cell lines over-expressing EGFR and HER2 have shown that lapatinib inhibits tyrosine phosphorylation in catalytic domain of EGFR and HER2 and prevents ERK1/2 and AKT activation which induces apoptosis of tumor cells (Xia et al., 2002).