CD44 and neoplasm: The idea of combining markers to increase the purity of subpopulations for CSCs was utilised by Ginestier et al. who showed that the combination of CD44+CD24-/low and ALDEFLUOR activity enabled the isolation of cells able to form tumours in NOD/SCID mice from as few as 20 cells, compared to 500 cells when sorted by ALDEFLUOR activity alone [3].