It is also of interest that the incidence of BRAF V600E mutations in undifferentiated anaplastic thyroid cancer is similar to that in well-differentiated early-stage tumours in several studies (Namba et al, 2003; Nikiforova et al, 2003; Begum et al, 2004; Soares et al, 2004; Trovisco et al, 2004; Trovisco et al, 2005) supporting the concept that some anaplastic thyroid cancers arise from more typical forms of PTC and suggesting that BRAF signalling may be functionally important in anaplastic thyroid cancers. The gene discussed is BRAF; the disease is thyroid gland undifferentiated (anaplastic) carcinoma.