ALDH1A1 and cancer: We further identified the stemness characteristics in the formed tumorspheres through quantitative reverse transcription PCR by measuring the expression of cancer stemness markers, namely Aldh1, Cd133, Oct4, and Nanog. The results indicated higher expression levels of Aldh1, Cd133, Oct4, and Nanog in the tumorspheres (HCC827 CSCs) than in parental HCC827 cells (Fig 1D).