ALDH1A1 and central nervous system cancer: Furthermore, the attenuation of UCA1 knockdown on the stemness of glioma cells was abrogated by Slug ectopic expression, evident by recovery of the capacity of cell spheroid formation (Fig. 6C,D), ALDH1 activity (Fig. 6E) and the expression of stemness markers (ALDH1 and Nanog) (Fig. 6F,G).