Dysregulation of microRNAs as the risk factor of lymph node metastasis in papillary thyroid carcinoma: systematic review

Abstract

Papillary thyroid carcinoma (PTC) has an excellent prognosis with a relatively low mortality rate, but a small portion of PTC patients suffer from an aggressive form of the disease. In such cases early detection of lymph node metastasis (LNM) is as paramount as it is problematic.The routine use of central neck lymph node dissection is not recommended. New methods to detect LNM are needed. MicroRNAs are a potential biomarker for diagnosis and prognosis of PTC. In this review we summarise the current knowledge regarding dysregulated miRNAs and their association with LNM in PTS patients. The PubMed and EBSCO databases were searched using terms for "microRNA", "thyroid carcinoma", and "prognosis" by using Boolean operators. Based on eligibility and exclusion criteria, articles were screened and reviewed in full, methodological data of included studies were extracted, and risk of bias analysis performed. In total, 446 unique studies were extracted from the mentioned databases, and based on inclusion and exclusion criteria 27 studies were included in this review. Of them 17 analysed tissue microRNAs, 5 analysed circulating microRNAs, and 5 studies analysed both tissue and circulating samples. were dysregulated in at least 2 separate studies. A sizable portion of studies failed to show statistically significant differences in miRNA expression between LNM-positive and -negative patients. Different methodologies and disparities of patient populations could explain these discrepancies. This research supports the statement that specific up-and downregulated miRNAs are associated with LNM in PTC patients. However, the prognostic value of these miRNAs is limited. Additional targeted cohort studies are required to elucidate the role of miRNAs in defining individualised treatment strategies for thyroid cancer patients.

Diagnostic Significance of FNAB miRNA Expression in Papillary Thyroid Carcinoma

“…Of these, the three most divergent miRNAs, miR4324, miR200B, miR125A, were selected for further validation. After the literature review, two more miRNAs, miR146B, miR221, which have been mainly described for differentiating both PTC with benign thyroid disease and more aggressive forms of PTC, were selected for further testing [ 20 ].…”

“…Over the last decade, several studies have been conducted to identify miRNAs associated with PTC metastasis [ 20 ]. Chou and co-authors demonstrated that miR146B expression is an independent risk factor for poor prognosis in PTC [ 35 ].…”

“…Based on the results of the sequencing, the three miRNAs that were most divergent between the groups—miR125A, miR200B, miR4324—were selected for further analysis. Following the literature review, two more miRNAs, miR146B and miR221, which have been mainly described for differentiating both PTC with benign thyroid disease and more aggressive forms of PTC [ 17 , 18 , 19 , 20 , 21 ], were selected for further investigation.…”

Expression Profile and Diagnostic Significance of MicroRNAs in Papillary Thyroid Cancer

“…Metastatic PTC were excluded to obtain homogenous PTC cohort, which was also helpful to comprehensively describe tumor-initiating alterations in miRNA expression pattern [ 37 ]. Literature data suggest distinct miRNA expression pattern associated with lymph node metastasis in PTC patients [ 38 ]. It is worth noting that the data on the diagnostic value of the miRNA profile in differentiation between metastatic PTC and non-metastatic PTC patients are limited.…”

MiR-29b-3p Inhibits Migration and Invasion of Papillary Thyroid Carcinoma by Downregulating COL1A1 and COL5A1

“…MiRNA dysregulation has been identified as a hallmark of human malignancies (10,29) and may be correlated with clinicopathological characteristics and disease activity of cancer (30)(31)(32). Several studies have demonstrated that miRNAs play an important role in the metastasis and progression of thyroid cancer (33)(34)(35)(36)(37)(38)(39). In the present study, we showed for the first time that miR-29b-3p expression was downregulated in PTC tissues as compared to normal tissues and was significantly negatively correlated in terms of tumor size, local lymph node metastasis, and TNM stage in patients with PTC.…”