Because the levels of phosphorylated AKT are increased (Figure 2) but the levels of Chk1 S280 phosphorylation are substantially reduced (Figure 8) in PLX4032-treated A375, A375-PLX-R, and WM9 cells, we suggested AKT plays limited role in Chk1 S280 phosphorylation in these melanoma cells. This evidence concerns the gene CHEK1 and melanoma.