Detection of TICs relies on the presence of the CD antigen 133 (CD133) surface marker of cancer stem cells [55], the expression of the cytoplasmic marker (KDM5A or histone deacetylase (HDAC) [56] or the over-activity of the aldehyde dehydrogenase 1 (ALDH1) [57,58]. Here, PROM1 is linked to cancer.