CD8A and melanoma: To test this possibility, we chose the A375 human melanoma cells, the most typical cancer for the clinical application of adoptive CD8+ T cell transfer therapy (ACT), and established an ACT-refractory A375 P3 model from parental A375 P0 cells by selection with NY-ESO1-specific CD8+ T cells (MAK #11) in vivo (Fig. 4a).