Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor comprising hereditary or sporadic form with frequent mutations in the rearranged during transfection (RET) or RAS genes. Diagnosis is based on presence of thyroid tumor mass with altered levels of calcitonin (Ctn) and carcinoembryonal antigen (CEA) in the serum and/or in the cytological smears from fine needle aspiration biopsies.

Treatment consists of total thyroidectomy, followed by tyrosine kinase inhibitors (TKi) in case of disease persistence. During TKi treatment, Ctn and CEA levels can fluctuate regardless of tumor volume, metastasis or response to therapy.

Research for more reliable non-invasive biomarkers in MTC is still underway. In this context, circulating nucleic acids, namely circulating microRNAs (miRNAs) and cell free DNA (cfDNA), have been evaluated by different research groups. Aiming to shed light on whether miRNAs and cfDNA are suitable as MTC biomarkers we searched three different databases, PubMed, Scopus, WOS and reviewed literature. We classified 83 publications fulfilling our search criteria and summarized the results. We report data on miRNA and cfDNA that can be evaluated for validation in independent studies and clinical application.

甲状腺髓样癌 (MTC) 是一种罕见的神经内分泌肿瘤，包括遗传性或散发性形式，在转染 (RET) 或 RAS 基因重排过程中经常发生突变。诊断基于血清和/或细针抽吸活检细胞学涂片中降钙素 (Ctn) 和癌胚抗原 (CEA) 水平改变的甲状腺肿瘤块的存在。

治疗包括全甲状腺切除术，然后在疾病持续存在的情况下使用酪氨酸激酶抑制剂 (TKi)。在 TKi 治疗期间，Ctn 和 CEA 水平会发生波动，无论肿瘤体积、转移情况或对治疗的反应如何。

对 MTC 中更可靠的非侵入性生物标志物的研究仍在进行中。在这种情况下，循环核酸，即循环微 RNA (miRNA) 和无细胞 DNA (cfDNA)，已被不同的研究小组评估过。为了阐明 miRNA 和 cfDNA 是否适合作为 MTC 生物标志物，我们搜索了三个不同的数据库，PubMed、Scopus、WOS 和文献综述。我们对符合搜索条件的 83 篇出版物进行了分类并总结了结果。我们报告了 miRNA 和 cfDNA 的数据，这些数据可以在独立研究和临床应用中进行评估以进行验证。