As shown in Fig. 4A-D, siRNA mediated MITF knockdown in 624Mel melanoma cells in combination with IFNγ (5 ng/mL) treatment significantly increased PD-L1 expression at both the RNA (Fig. 4B; one-way ANOVA, P < 0.01) and protein levels (Fig. 4D; one-way ANOVA, P < 0.001) compared to the expected increase caused by IFNγ treatment alone. Here, MITF is linked to melanoma.