MYC and neoplasm: MEK is a key downstream element of the RAS-RAF pathway able to indirectly activate Myc.15 Replacement of vemurafenib with MEK inhibitors in the triple combination was able to significantly limit ERK activation and downregulate Myc expression while inducing a considerable therapeutic response in Braf-mutated and Kras-mutated tumours progressing after the vemurafenib-based combination.