In breast cancer model, a loss of ARID1A expression sensitizes cancer cells to PI3K- and AKT-inhibition and knockdown of ARID1A in MCF7 increased pAKT-Ser473 while treatment with MK-2206 increased apoptosis and decreases pS6K in ARID1A-depleted MCF7 cells. This evidence concerns the gene PIK3CA and cancer.