TP53 and lung cancer: The chief signaling pathways that may provide roadmaps for lung cancer therapy are growth-stimulating pathways (EGFR/Ras/PI 3-kinase), growth inhibitory pathways (Rb/p53/P14ARF/STK11), apoptotic pathways (Bax/Bcl-2/FasL/Fas), DNA repair and immortalization genes [18].