ALDH1A1 and neoplasm: Reverse transcription polymerase chain reaction (RT-PCR) revealed that CD133+ cell populations showed higher mRNA levels of stemness-associated genes, including NANOG, SOX2, ALDH1A1, and OCT4, than CD133− cells (P < 0.05) (Fig. 4B), suggesting that CD133+ cells from OSCC tumours showed more aggressive tumour stem cell behaviour.