A total of 57 nonthyroid papillary tumors were examined for RET/PTC rearrangements using interphase fluorescence in situ hybridization, Taqman reverse transcriptase polymerase chain reaction, and immunohistochemistry.     ///    No RET/PTC1 rearrangements were detected in the remaining tumor cohort.     ///    A further case of similar histotype had an alternate RET/ PTC rearrangement.     ///    The results indicate that RET/PTC rearrangements occur in a small subset of nonthyroid papillary tumors.     ///    RET/PTC rearrangement occurring in primary peritoneal carcinoma..     ///     RET/PTC rearrangements are initiating events in the development of a significant proportion of papillary thyroid carcinomas.     ///    "In all, 20% (3/15) of primary peritoneal carcinoma had detectable RET/PTC1 rearrangements by all 3 methodologies. "    ///    "Activated RET/PTC mutations are thought to be restricted to thyroid disease, but this study proposes that these events may also occur in nonthyroid tumors. "