AKT1 and cancer: However, interferences in PI3K pathway activity are even more frequent in basal-like tumors and include loss of PTEN and INPP4B. Furthermore, in basal-like cancers, many of the elements of the PI3K/AKT/mTOR and RAS/RAF/MEK/MAPK pathways were amplified, including PIK3CA (49%), KRAS (32%), BRAF (30%), and EGFR (23%) [17].