Next, we analysed tumours that showed melanoma recurrence on vemurafenib pellets, and found that although the responses were varied, on average, tumours exhibited increased levels of phospho-Erk1/2, consistent with those seen in patients (Manzano et al., 2016; Proietti et al., 2020) (Fig. 4A,B). This evidence concerns the gene MAPK3 and melanoma.