Effect of p53 co-mutation in KRASG12C mouse lung tumors on efficacy of cisplatin/pemetrexed treatment alone or in combination with selumetinib. A, Schematic of KRASG12C/p53R270H breeding strategy. B, KCP tumor volume change 1 to 3 weeks after treatment with cisplatin/pemetrexed alone (n = 8), selumetinib alone (n = 5) or in their combination (n = 6). Each dot represents one mouse. C, Progression-free survival of KCP mice treated with cisplatin/pemetrexed alone, selumetinib alone or their combination.