ERBB2 and cancer: In malignant diseases, many tumorigenic pathways, such as those conferred by oncogenic receptors PDGF-R, EGF-R, and HER2, by widespread increases in PI-3 kinase and loss of the phosphatase PTEN often encountered in cancer, converge on the kinase Akt that is a GSK3 repressor (Yuan and Cantley, 2008; Chalhoub and Baker, 2009).