H2BC21 and melanoma: As expected for melanoma SCs, live GFPhigh cells over-expressed ABCB5 and CD271 surface markers, conferring their CSC phenotype [19,20,30], and consistently, TNF significantly (p < 0.01) increased the pool of GFPhighABCB5high (Figure 3D) and GFPhighCD271high (2.0x ±0.2, data not shown) cells in HBL-H2B-GFP and, to a lesser extent, in SK-Mel28-H2B-GFP (1.6x ±0.2 and 1.7x ±0.6, respectively, data not shown) cell lines.