RESUMO
Objective To investigate the association of ret gene rearrangement mutation with the pathogenesis of papillary thyroid carcinoma (PTC). Methods Twenty-seven cases of PTC were analysed for expression of ret gene rearrangement (ret/PTCs) by multiplex-PCR at first, and then ret/PTC1-3 were identified by identification-PCR (ID-PCR). Finally, the specific ret/PTC was affirmed by automated direct sequencing. Ten specimens of malignant thyroid tissues of other histological types, 33 benign thyroid lesions and 30 normal thyroid specimens beside tumor (as the control) were also included. Results (1) Fifteen samples showed positive ret/PTCs, 11 of which harboured ret/PTC1,3 were positive for ret/PTC3, and 1 for ret/PTC2. All the rearrangements were clearly identified by automated direct sequencing of ID-PCR products. (2) All the 15 ret/PTC-positive tissue samples were histologically confirmed to be PTC. The prevalence of the tumor-specific ret rearrangements in 27 patients with PTC is 55.6% (15/27). (3) No significant difference was found regarding the gender and age of the patients, tumor size and metastasis of neck lymph node. 33.3% (2/6) of the PTC with invasion of extrathyroidal soft tissue were ret/PTC-positive, as compared with 66.7%(4/6) for ret/PTC-negative group (P