PSEN2 and melanoma: In our melanoma model, the expression of these genes is increased in the tumor cell lines (Figure 6A) and, as hypothesized, there was a significant reduction of Cdkn1a, Bcl2 and Psen2 expression in SIRT1-silenced 4C11+ melanoma cell line (Figure 6B–6D, respectively) compared to non-silenced cell lines.