First of all, CD133 is still a candidate but not a definite CSC marker, for example, results from Rocco A [40] showed that neither CD133 nor CD44 can be an eligible marker to isolate cancer stem cells; some other studies revealed that not only CD133-positive, but also CD133-negative ones can initiate a tumor [41]–[42]. Here, PROM1 is linked to neoplasm.