Melanoma RPMI-7951 and A375 cell culture supernatants did not induce a significant MC degranulation at any time point upon incubation measured by CD63 expression and β-hexosaminidase release, while MC degranulation was observed in MC treated with the calcium ionophore A23187 used as positive control (Figure 4A and Supplementary Figure 6A). This evidence concerns the gene CD63 and melanoma.