ERBB2 and neoplasm: Protein phosphatase 2A (PP2A), a ubiquitous serine/threonine phosphatase, is also a central regulatory component of PI3K/Akt pathway; its inactivation through phosphorylation at its tyrosine residue p.tyr307 has been found to be increased in HER2-positive tumor samples and correlated to tumor progression (4).