BRAF and thyroid cancer: Since the first identification of the BRAF gene mutation in human cancer [5], accumulating evidence has shown that a considerable proportion of various human malignancies, such as malignant melanoma (~50%) and other solid cancers including thyroid cancer (~60%), colorectal cancer (~10%), and lung cancer (~6%) carry the activated BRAF mutations, which leads to constitutive activation of downstream RAF, MEK and ERK [1].