TP53 and lung cancer: As TP53 is the most commonly mutated gene in lung cancer (Robles and Harris, 2010), we examined TP53 somatic mutations and found that 50% of smokers (21 out of 42) and 22% (22 out of 101) of non-smokers were positive for TP53 mutation, indicating TP53 mutation was more prevalent in tobacco-related lung cancer (Figure 3C).