Expression of wild-type RET and RET/PTC fusion gene in papillary thyroid carcinoma

Objective To explore the relationship between wild type RET (WT-RET) and RET/PTC fusion gene expression and the development of papillary thyroid carcinoma (PTC). Methods 35 cases of fresh PTC tissues, the corresponding paracancerous thyroid tissues and 10 cases of fresh adjacent benign thyroid lesions normal tissues were collected. Expression of RET/PTC 1, 2 and 3 fusion gene were detected by Nested PCR and DNA sequence test. Expression of WT-RET and RET tyrosine kinase (RET-TK)mRNA were detected by quantitative Real Time PCR. RET mRNA expression in the source was detected by in situ hybridization. Results Among the 35 cases of PTC,17 cases had positive RET/PTC fusion gene (15 cases of positive RET/PTC 1, 0 case of positive RET/PTC 2 was, 2 cases of positive RET/PTC 3), and all positive cases were confirmed by DNA sequence test. Almost no expression of WT-RET and RET-TK mRNA was found in paracancerous thyroid tissues, while their expressions in RET/PTC negative group were 2 times higher than those in the respective paracancerous thyroid tissues (P 0.05). Expression of RET-TK mRNA in RET/PTC positive group was significantly higher than that in the negative group, and the difference has statistical significance (P 0.05). Conclusions ①Expression ratio of RET/PTC positive is not high in sporadic PTC in Anhui province, and its diagnostic and prognosis significance is limited.②Expression of WT-RET in follicular cells in sporadic PTC may promote the occurance of RET/PTC fusion gene, and the two may commonly involved in the occurrence of thyroid tumor. Key words: Thyroid neoplasms; Papillary thyroid carcinoma; Oncogene proteins; Fusion; Gene rearrangement