IHC analysis of RET/PTC rearrangements revealed no positive staining of RET in any of 8 ATCs, suggesting that these ATCs are not derived from RET/PTC- rearranged PTC.     ///    "RET/PTC rearrangements and p53 mutation were monitored by immunohistochemical (IHC) staining by anti-RET antibodies and an anti-p53 mAb, respectively. "