RET/PTC rearrangements are frequent in thyroid cancer and appear to be exclusive from mutational events in RAS and BRAF.     ///    "We further propose that if mutations in BRAF, RAS, and RET/PTC rearrangements are mutually exclusive in certain thyroid tumors or tumor types, as has already been shown for papillary thyroid cancer, then these interconnected pathways may cooperate in the initiation and promotion of the disease. "