Approximately 10-15% of CRCs are dMMR, among which 80% are sporadic owing to MLH1 promoter hypermethylation or v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) mutations, whereas 20% are due to autosomal dominant germline mutations, termed Lynch syndrome (LS) [7]. The gene discussed is BRAF; the disease is Lynch syndrome.