PIK3CA and cancer: Upregulation of AKT by mutation of PTEN (a tumour suppressor gene that antagonises AKT pathway) or amplification PIK3CA (encodes catalytic subunit of PI3-K) were reported in a number of human cancers including breast carcinoma (Vivanco and Sawyers, 2002; Lee et al, 2005; Levine et al, 2005).