Treatment with EGCG and siAXL similarly induced the following inhibitory effects on the H1299-sdCSCs: 1) a reduction in tumour sphere formation; 2) inhibition of ALDH1A1 and SNAI2 (Slug) but not other stemness markers or EMT-related genes; and 3) a reduction in aldehyde dehydrogenase (ALDH)-positive cells. Here, ALDH1A1 is linked to neoplasm.