HER2 (ErbB2 or HER-2/neu) belongs to the human epidermal growth factor receptor (HER) family and is significantly correlated with the proliferation, migration, and differentiation of many kinds of cancer cells through its involvement in the activation of the PI3K/Akt and Ras/Raf/MEK/MAPK pathways. This evidence concerns the gene ERBB2 and cancer.