ALDH1A1 and neoplasm: The tumor tissue was further analyzed by double immunofluorescence staining (Fig. 4E), which demonstrated that sulforaphane and TRAIL reduced the expression of the CSC markers CD133, CXCR4, Nanog, c-Met, EpCAM, CD44, and ALDH1 and the proliferation marker Ki67; the inhibition was much more pronounced with the combination of sulforaphane and TRAIL.