AKT1 and breast cancer: Another recent study confirmed these findings; in fact, Banerji and coworkers reported five genes to be frequently mutated in breast cancer: TP53 and PI3KCA, both in 27% of cases; AKT1 in 6% of cases; MAPK1 in 6% of cases; and, GATA3 in about 4% of patients (both AKT1 and PI3KCA mutations activate the PI3K pathway and are mutually exclusive) [39].