Inhibition of Akt activation by treating with PI3K inhibitor LY294002 decreased IR cell invasion, yet MEK inhibitor U0126 did not inhibit Erk1/2 activation, which indicates integrin α2β1 and EGFR mutually promote higher invasiveness mediated by the PI3K/Akt signaling pathway in IR-survived lung cancer cells and might provide alternative targets along with radiotherapy (217). Here, AKT1 is linked to lung cancer.