MAP2K1 and colonic neoplasm: Consistent with previous findings in literature [1,9], we confirmed elevated expression levels of phospho-c-RAF, phospho-ERK1/2, phospho-MEK1/2 and phospho-AKT in resistant cell lines under basal conditions and especially upon the treatment with PLX4032 (Supplementary Figure S2), which again demonstrated that activation of the RAF/MEK/ERK and AKT signalling could be associated with the development of vemurafenib-resistant phenotype in colon cancer.