PIK3CA and neoplasm: Amplification and overexpression of PIK3CA results in increased production of the phosphatidylinositol-3,4,5-triphosphate second messenger, hyperactivation of the PI3K/AKT pathway, and stimulation of cellular transformation and tumour progression (Shayesteh et al, 1999; Ma et al, 2000; Fresno Vara et al, 2004; Saal et al, 2005; Samuels and Ericson, 2006).