ARSB activity declined from 138 ± 7 nmol/mg protein/h in the normal melanocytes to 71 ± 1 nmol/mg protein/h in the metastatic melanoma cell line (p < 0.001, 1-way ANOVA with Tukey-Kramer post-test for M0 vs. other cell lines) (Figure 1A). This evidence concerns the gene ARSB and melanoma.