In agreement with our findings with BRAF inhibitor-resistant melanoma, it has been shown using BRAF/MEK-resistant melanoma PDX and next-generation sequencing that the MAPK pathway activation represents a common mechanism of resistance to BRAF/MEK therapy.40 Inhibition of MET, RTK and IGF1R can each impact MAPK signalling at various levels, although the upstream inhibition of MAPK through IGF1R appears to be more efficient, at least in two of the three BRAF inhibitor-resistant PDXCs. Here, IGF1R is linked to melanoma.