In particular, these tumours are characterised by a high frequency of carrying BRAF mutation and a high frequency of CpG island methylation (CpG island methylator phenotype-high) (Park et al, 2003; Kambara et al, 2004; O’Brien et al, 2004), and are considered precursor lesions of CRC with microsatellite instability. The gene discussed is BRAF; the disease is colorectal carcinoma.