PIK3CA and brain ischemia: Accumulating evidence has confirmed that, under the injuries of stroke, cerebral ischemia, and I/R and activation of PI3K/Akt or PI3K/Akt/mTOR signaling pathway, PIK3CA, PIK3R1, AKT1, MAPK1, MAPK3 are main genes that play important roles in promoting cell survival and reducing cellular apoptosis [79, 80].