We therefore down-regulated the expression of MITF in both parental and resistant melanoma cells by using MITF siRNA (interfering efficiencies shown in Fig. 5c, d) and found that knocking down MITF also restored the sensitivity of melanoma cells to Vemurafenib (Fig. 5e, f), However, this effect was significantly weaker than knocking down POU4F1, demonstrating that MITF is one of the downstream targets of POU4F1 in the formation of resistance of melanoma to BRAFi. The gene discussed is MITF; the disease is melanoma.