SOX2 and neoplasm: In addition and irrespective of tumor histology, SOX2 protein expression was statistically significantly higher in ever compared to never smokers (set I, p = 0.002; set II, p<0.001) (Figure 3B) and was also significantly increased in current or former smokers compared to never smoker NSCLC patients (set I, p = 0.008; set II, p<0.001) (Figure 3C).