Therefore, the latest NCCN guideline strongly recommends genotyping of tumour tissue (either primary tumour or metastasis) in all patients with metastatic colorectal cancer for RAS and BRAF. However, most of these reports perform the mutation test using Sanger sequencing or ARMS-PCR, which may be limited by low sensitivity or detection of common mutations (Artale et al. 2008; Knijn et al. 2011; Santini et al. 2008). This evidence concerns the gene BRAF and metastatic colorectal cancer.