Our finding that Oct-4 and Sox-2 are highly upregulated in radiation survived sphere cells from the A549 cell line and highly upregulated in radiation surviving adherent H460 cells, in comparison to respective naïve lung adherent NSCLC cells and sphere cells, is suggesting that radiation treatment may select for aggressive tumorigenic phenotype, and that this selection is cell line specific. This evidence concerns the gene POU5F1 and non-small cell lung carcinoma.