. 2015 Sep 8;7(2):89–99. doi: 10.1007/s13238-015-0199-4

Box 1.

Different types of breast cancer stem cells

ALDH⁺ and CD24⁻CD44⁺ are different markers for breast cancer stem cells (BCSCs) (Liu et al., 2014). CD24⁻CD44⁺ marks BCSCs in a mesenchymal-like (EMT) state, primarily quiescent, and localized at the tumor invasion front; ALDH⁺ marked BCSCs with epithelial-like (MET) state, proliferative, and localized at the tumor center. They both can self-renew and differentiate. The tumorigenesis ability of BCSCs in the overlap of ALDH⁺ and CD24⁻CD44⁺ is the highest. These two types of BCSCs can reciprocally transform, which could be induced by tumor microenvironmental factors, microRNAs, lncRNAs or epigenetic proteins.