in only three was this explained by expression of a RET/PTC rearrangement.     ///    Sixty-one PTCs were analysed for expression of RET and the oncogenes RET/PTC1-4 by polymerase chain reaction of complementary DNA.     ///    "One tumour expressed RET/PTC3, one a variant of RET/PTC3, and one RET/PTC1 and WT-RET simultaneously. "