RB1 and melanoma: In light of the intrinsic resistance to vemurafenib (and its analog PLX4720) shown by the 1205lu BRAF‐mutant melanoma cell line (Paraiso et al., 2011), we also evaluated vemurafenib and dabrafenib on two highly sensitive BRAF‐mutant melanoma cell lines (WM164 and A375) and found both vemurafenib and dabrafenib to be equivalent at inhibiting pRb phosphorylation and inducing p27 expression (Fig. 6A).