RT-PCR and densitometric quantification analysis was used to quantify mRNA expression of a panel of stemness genes (NANOG, OCT-4, SOX-2, KLF4 and C-MYC), in addition to the CSC-specific markers, CD133 and ALDH1, in a cohort of matched normal and tumor lung tissues from NSCLC patients (n=20). Here, KLF4 is linked to neoplasm.