PIK3CA and cancer: The blockade of RAS/RAF/ERK (pERK) and PI3K/AKT (pAKT) pathways has been associated with gefitinib sensitivity in other cancer cell lines and xenografts, such as NSCLC cell lines A549, H460, PC9, A549 and QG56, which carry intrinsically active ERK or AKT pathways [21, 43].