RET proto-oncogene (RET) mutations were proved to be related to the development of medullary thyroid carcinoma (MTC). We aimed to analyze the role of RET mutations in cervical lymph node metastasis in patients with MTC. Forty-nine patients with preoperatively diagnosed MTC by fine-needle aspiration cytology (FNAC) who underwent bilateral total thyroidectomy with cervical lymphadenectomy were included. Postoperative RET gene test and pathological analysis were performed with the surgical specimens; serum calcitonin (Ctn) and carcinoembryonic antigen (CEA) levels were tested pre- and postoperatively, to evaluate the association between RET mutations and cervical lymph node metastasis in MTC. In these 49 patients, the RET mutation rates of Exon 11, Exon 10, Exon 11&13, Exon 13, and Exon 16 were 20.4%, 4.1%, 38.8%, 22.4%, and 0%, respectively. The lymph node metastasis rates of patients with RET mutation in the central and lateral compartments were 71.4% and 64.3%, respectively, versus 28.6% and 14.3% of patients without RET mutation. The preoperative basal serum levels of Ctn (234.8 ± 188.4 vs. 44.4 ± 27.5, p < 0.01) and postoperative Ctn (49.8 ± 86.4 vs. 3.7 ± 2.2, p = 0.001) in MTC patients with RET mutations were significantly higher than those in MTC patients without RET mutation. In addition, the preoperative (50.2 ± 76.7 vs. 7.4 ± 6.8, p = 0.001) and postoperative serum levels of CEA (13.2 ± 19.5 vs. 1.3 ± 1.6, p < 0.01) in MTC patients with RET mutations were significantly higher than those in MTC patients without RET mutation (p < 0.05). RET mutation was related to cervical lymph node metastasis in patients with MTC, especially the mutation in Exon 11&13. Patients with RET mutation in Exon 11&13 might be regarded as the predictor for prophylactic ipsilateral total cervical lymphadenectomy even without clear evidence of lateral cervical lymph node metastasis.
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This study was supported by the National Key Clinical Specialty Discipline Construction Program of China (Grant Nos. 81472777, 30872479).
Compliance with Ethical Standards
This study was approved by the local Ethics Committee. All patients provided written informed consent before participating in the study.
Conflict of Interest
The authors declare that they have no conflicts of interest.
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