Protein kinase treatments are evolving rapidly, with vemurafenib as the first BRAF inhibitor on the market now indicated for metastatic malignant melanoma,21 and a combination treatment with MEK inhibitors has been shown to improve the response rate compared with BRAF monotherapy.22 However, metastatic colorectal cancer has not responded well to BRAF inhibitors used as monotherapy, and it is thought that BRAF inhibitors will have to be used together with other targeted drugs or chemotherapy. This evidence concerns the gene BRAF and metastatic colorectal cancer.