ABCB5 and melanoma: In melanoma, cells with CSC properties are called melanoma-initiating cells (MICs) and were characterized by the expression of surface markers including CD20 [10], ABCB5 [11,12,13], CD133 [14,15], and CD271 [16,17,18,19] and functional features such as the high activity of aldehyde dehydrogenases (ALDHs) [20], ability to efflux Hoechst 33342 (so-called “side population”) [21], and slow proliferation rate [22,23,24].