The activation of this pathway is most notable in cancers that have either inactivating mutations of the PTEN gene (e.g. glioblastoma, melanoma, prostate cancer and endometrial carcinomas) or overexpression of an activated member of the epidermal growth factor (EGF) receptor family (e.g. Her2/neu in breast cancer) (Luo et al, 2005). The gene discussed is ERBB2; the disease is breast cancer.