CircTP53 promotes the proliferation of thyroid cancer via targeting miR-1233-3p/MDM2 axis

Exploration of the prognostic value of methylation regulators related to m5C in papillary thyroid carcinoma

The incidence of papillary thyroid carcinoma (PTC) has increased significantly in recent years, and for patients with metastatic and recurrent PTC, the options for treatment currently available are insufficient. To date, the exact molecular mechanism underlying PTC is still not fully understood. 5-Methylcytosine (m5C) RNA methylation is associated with the prognosis of a variety of tumors. However, the molecular mechanisms and biomarkers associated with m5C in the diagnosis, treatment, and prognosis of this disease have not been fully elucidated. Ten m5C regulators with significantly different expression levels were included in this study. Immune infiltration analysis revealed significant negative correlations between most of these regulators and regulatory T cells. TRDMT1, NSUN5, and NSUN6 had high weights and strong correlations in the protein-protein interaction network. Using gene ontology, Kyoto Encyclopedia of Genes and Genomes, and gene set enrichment analysis, 1489 differentially expressed genes were screened from The Cancer Genome Atlas messenger RNA matrix, indicating that these differentially expressed genes were significantly enriched in various pathways and functions related to cancers. Four m5C regulators, NSUN2, NSUN4, NSUN6, and DNMT3B, were screened as prognostic markers by least absolute shrinkage and selection operator regression analysis, and NSUN2 and NSUN6 were identified as risk factors for poor prognosis. We found that the prognostic prediction model constructed using the m5C regulators NSUN2, NSUN4, NSUN6, and DNMT3B showed good prognostic prediction ability and diagnostic ability. This model was applied to predict the survival probability of patients with PTC, the prediction ability of 5-year survival was the best. The multi-factor prognostic prediction model combined with the tumor node metastasis stage and risk score grouping showed better prognostic predictive power.

Emerging roles of circular RNAs in regulating the hallmarks of thyroid cancer

Thyroid cancer is a prevalent endocrine malignancy with increasing incidence in recent years. Although most thyroid cancers grow slowly, they can become refractory, leading to a high mortality rate once they exhibit recurrence, metastasis, resistance to radioiodine therapy, or a lack of differentiation. However, the mechanisms underlying these malignant characteristics remain unclear. Circular RNAs, a type of closed-loop non-coding RNAs, play multiple roles in cancer. Several studies have demonstrated that circular RNAs significantly influence the development of thyroid cancers. In this review, we summarize the circular RNAs identified in thyroid cancers over the past decade according to the hallmarks of cancer. We found that eight of the 14 hallmarks of thyroid cancers are regulated by circular RNAs, whereas the other six have not been reported to be correlated with circular RNAs. This review is expected to help us better understand the roles of circular RNAs in thyroid cancers and accelerate research on the mechanisms and cure strategies for thyroid cancers.

Forkhead box F2/ Lysyl oxidase like 1 contribute to epithelial-mesenchymal transition and angiogenesis in thyroid cancer

BACKGROUND

Bioinformatics analysis suggests an association between lysyl oxidase like 1 (LOXL1) and forkhead box F2 (FOXF2), both of which are found to be dysregulated in thyroid cancer. This study aims to elucidate their specific roles in thyroid cancer.

METHODS

The correlation of LOXL1 expression with thyroid cancer staging and the overall survival was analyzed. LOXL1 levels were determined in several thyroid cancer cells, and its effects on poorly differentiated BCPAP cell proliferation, colony formation, malignant phenotypes, epithelial-mesenchymal transition (EMT) progression, and angiogenesis were evaluated. The relationship between LOXL1 and FOXF2 was confirmed using Luciferase reporter and ChIP assays. The impacts of FOXF2 on LOXL1 regulation along with the Wnt/β-catenin signaling were assessed, followed by the verification of transplanted tumor in nude mice.

RESULTS

Elevated LOXL1 expression was associated with advanced clinical staging and poorer overall survival. Reduced LOXL1 suppressed cell proliferation, colony formation, migration, invasion, EMT, and angiogenesis. FOXF2 was found to be down-regulated in thyroid cancer, acting as a transcription factor that recognizes the LOXL1 promoter and modulates its transcriptional expression. Moreover, the regulatory outcome of LOXL1 knockdown was partially reversed upon FOXF2 knockdown, including the modulation of the Wnt/β-catenin signaling and tumor growth in vivo.

CONCLUSION

Our findings indicate that LOXL1 is transcriptionally regulated by FOXF2 and activates the Wnt/β-catenin to promote malignant phenotypes, EMT progression, and angiogenesis in BCPAP cells.

ELOVL2-AS1 suppresses tamoxifen resistance by sponging miR-1233-3p in breast cancer

Tamoxifen (Tam) has long been a top treatment option for breast cancer patients, but the challenge of eliminating cancer recurrence remains. Here, we identify a signalling pathway involving ELOVL2, ELOVL2-AS1, and miR-1233-3p, which contributes to drug resistance in Tam-resistant (TamR) breast cancer. ELOVL2-AS1, a long noncoding RNA, was significantly upregulated by its antisense gene, ELOVL2, which is known to be downregulated in TamR cells. Additionally, ELOVL2-AS1 underwent the most hypermethylation in MCF-7/TamR cells. Furthermore, patients with breast cancer who developed TamR during chemotherapy had significantly lower expression of ELOVL2-AS1 compared to those who responded to Tam. Ectopic downregulation of ELOVL2-AS1 by siRNA both stimulated cancer cell growth and deteriorated TamR. We also found that ELOVL2-AS1 sponges miR-1233-3p, which has pro-proliferative activity and elevates TamR, leading to the activation of potential target genes, such as MYEF2, NDST1, and PIK3R1. These findings suggest that ELOVL2-AS1, in association with ELOVL2, may contribute to the suppression of drug resistance by sponging miR-1233-3p in breast cancer.

The Analysis of Selected miRNAs and Target MDM2 Gene Expression in Oral Squamous Cell Carcinoma

MiRNAs could play an important role in tumorigenesis and progression. The oncoprotein MDM2 (murine double minute 2) was identified as a negative regulator of the tumour suppressor p53. This study aims to analyse the expression of the MDM2 target miRNA candidates (miR-3613-3p, miR-371b-5p and miR-3658) and the MDM2 gene in oral squamous cell carcinoma tumour and margin samples and their association with the selected socio-demographic and clinicopathological characteristics. The study group consisted of 50 patients. The miRNAs and MDM2 gene expression levels were assessed by qPCR. The expression analysis of the miRNAs showed the expression of only one of them, i.e., miR-3613-3p. We found no statistically significant differences in the miR-3613-3p expression in tumour samples compared to the margin samples. When analysing the effect of smoking on miR-3613-3p expression, we demonstrated a statistically significant difference between smokers and non-smokers. In addition, we showed an association between the miR-3613-3p expression level and some clinical parameters in tumour samples (T, N and G). Our study demonstrates that miR-3613-3p overexpression is involved in the tumour progression of OSCC. This indicates that miR-3613-3p possesses potential prognostic values.

The potential role and mechanism of circRNAs in foam cell formation

Atherosclerosis is a significant risk factor for coronary heart disease (CHD) and myocardial infarction (MI). Atherosclerosis develops during foam cell generation, which is caused by an imbalance in cholesterol uptake, esterification, and efflux. LOX-1, SR-A1, and CD36 all increased cholesterol uptake. ACAT1 and ACAT2 promote free cholesterol (FC) esterification to cholesteryl esters (CE). The hydrolysis of CE to FC was aided by nCEH. FC efflux was promoted by ABCA1, ABCG1, ADAM10, and apoA-I. SR-BI promotes not only cholesterol uptake but also FC efflux. Circular RNAs (circRNAs), which are single-stranded RNAs with a closed covalent circular structure, have emerged as promising biomarkers and therapeutic targets for atherosclerosis due to their highly tissue, cell, and disease state-specific expression profiles. Numerous studies have shown that circRNAs regulate foam cell formation, acting as miRNA sponges to influence atherosclerosis development by regulating the expression of SR-A1, CD36, ACAT2, ABCA1, ABCG1, ADAM10, apoA-I, SR-B1. Several circRNAs, including circ-Wdr91, circ 0004104, circRNA0044073, circRNA_0001805, circDENND1B, circRSF1, circ 0001445, and circRNA 102682, are potential biomarkers for atherosclerosis to better evaluate cardiovascular risk. It is difficult to deliver synthetic therapeutic circRNAs to the desired target tissues. Nanotechnology, such as GA-RM/GZ/PL, may be an important solution to this problem. In this review, we focus on the potential role and mechanism of circRNA/miRNA axis in foam cell formation in the hopes of discovering new targets for the diagnosis, prevention, and treatment of atherosclerosis.

A Review and In Silico Analysis of Tissue and Exosomal Circular RNAs: Opportunities and Challenges in Thyroid Cancer

Simple Summary

Thyroid cancer is the most common endocrine neoplasm. Recently, knowledge of the molecular genetic changes of thyroid cancer has dramatically improved. Understanding the roles of these molecular changes in thyroid cancer tumorigenesis and progression is essential in developing a successful treatment strategy and improving disease outcomes. As a family of non-coding RNAs, circular RNAs (circRNAs) have been involved in several aspects of the physiological and pathological processes of the cells. The roles of circRNAs in cancer development and progress are evident. In the current review, we aimed to explore the clinical potential of circRNAs as potential diagnostic, prognostic, and therapeutic targets in thyroid cancer. Furthermore, screening the genome-wide circRNAs and performing functional enrichment analyses for all associated dysregulated circRNAs in thyroid cancer have been done. Given the unique advantages circRNAs have, such as superior stability, higher abundance, and presence in different body fluids, this family of non-coding RNAs could be promising diagnostic and prognostic biomarkers and potential therapeutic targets for thyroid cancer.

Abstract

Thyroid cancer (TC) is the most common endocrine tumor. The genetic and epigenetic molecular alterations of TC have become more evident in recent years. However, a deeper understanding of the roles these molecular changes play in TC tumorigenesis and progression is essential in developing a successful treatment strategy and improving patients’ prognoses. Circular RNAs (circRNAs), a family of non-coding RNAs, have been implicated in several aspects of carcinogenesis in multiple cancers, including TC. In the current review, we aimed to explore the clinical potential of circRNAs as putative diagnostic, prognostic, and therapeutic targets in TC. The current analyses, including genome-wide circRNA screening and functional enrichment for all deregulated circRNA expression signatures, show that circRNAs display atypical contributions, such as sponging for microRNAs, regulating transcription and translation processes, and decoying for proteins. Given their exceptional clinical advantages, such as higher stability, wider abundance, and occurrence in several body fluids, circRNAs are promising prognostic and theranostic biomarkers for TC.

Function and Clinical Significance of Circular RNAs in Thyroid Cancer

Thyroid cancer (TC) is the leading cause and mortality of endocrine malignancies worldwide. Tumourigenesis involves multiple molecules including circular RNAs (circRNAs). circRNAs with covalently closed single-stranded structures have been identified as a type of regulatory RNA because of their high stability, abundance, and tissue/developmental stage-specific expression. Accumulating evidence has demonstrated that various circRNAs are aberrantly expressed in thyroid tissues, cells, exosomes, and body fluids in patients with TC. CircRNAs have been identified as either oncogenic or tumour suppressor roles in regulating tumourigenesis, tumour metabolism, metastasis, ferroptosis, and chemoradiation resistance in TC. Importantly, circRNAs exert pivotal effects on TC through various mechanisms, including acting as miRNA sponges or decoys, interacting with RNA-binding proteins, and translating functional peptides. Recent studies have suggested that many different circRNAs are associated with certain clinicopathological features, implying that the altered expression of circRNAs may be characteristic of TC. The purpose of this review is to provide an overview of recent advances on the dysregulation, functions, molecular mechanisms and potential clinical applications of circRNAs in TC. This review also aimes to improve our understanding of the functions of circRNAs in the initiation and progression of cancer, and to discuss the future perspectives on strategies targeting circRNAs in TC.

CircMCTP2 (has-circ-0000658) facilitates the proliferation and metastasis of bladder carcinoma through modulating the miR-498/murine double minute-2 axis

CircMCTP2 is a novel circRNA, which is associated with various kinds of malignant tumors progression, such as gastric cancer. However, the function of circMCTP2 in bladder carcinoma (BC) has no idea. The purpose of this study was tantamount to functionally dissect circMCTP2 in the progression of BC. In our study, circMCTP2 expression was strongly increased in BC tissues and cell lines. High expression of circMCTP2 predicted a poor prognosis of BC patients. CircMCTP2 deficiency impaired the cell growth, migration as well as invasive ability of BC cell lines (J82 and T24). In vivo, circMCTP2 deficiency cut the tumor growth rates and the tumor weight. In BC cells, circMCTP2 deficiency enhanced the translation of E-cadherin, while diminishing the translation of N-cadherin, Vimentin, and Snail. Moreover, circMCTP2 acted as a sponge of miR-498 to regulate murine double minute-2 (MDM2) expression. In BC tissues, a negative correlation was observed between the expression levels of circMCTP2 and miR-498. Additionally, either miR-498 silencing or MDM2 over-expression augmented the carcinogenic action of circMCTP2 on BC. In conclusion, our study showed that circMCTP2 regulates the expression of MDM2 by sponging miR-498 to promote the development of BC. These findings offer a new strategy for early diagnosis of BC and its therapeutics.

circSSU72 Promotes Cell Proliferation, Migration and Invasion of Papillary Thyroid Carcinoma Cells by Targeting miR-451a/S1PR2 Axis

Introduction: Thyroid cancer is the most common endocrine malignancy with Papillary Thyroid Carcinoma (PTC) as the most common pathological type. Due to low mortality but a high incidence, PTC still causes a relatively heavy burden on financial costs, human health, and quality of life. Emerging researches have indicated that circular RNAs (circRNAs) play a significant regulatory role in various cancers, including PTC. However, the functions and mechanisms of circRNAs derived from SSU72 remain unknown.

Method: The expression level of circRNAs derived from the exons of SSU72, miR-361–3p, miR-451a, and S1PR2 was evaluated by qRT-PCR assay or western blot assay. The interactions between circSSU72 (hsa_circ_0009294), miR-451a, and S1PR2 were verified by dual-luciferase reporter assay. Effects of circSSU72, miR-451a, and S1PR2 on cell proliferation, migration, and invasion were confirmed by colony formation assay, cell counting kit-8 (CCK-8), wound healing assay, and Transwell assays in vitro.

Results: circSSU72 was upregulated in PTC; circSSU72 knockdown inhibited PTC cell proliferation, migration, and invasion. In addition, circSSU72 could negatively regulate miR-451a by functioning as a sponge. circSSU72 promoted PTC cell proliferation, migration, and invasion by targeting miR-451a in vitro. We further found that miR-451a inhibited PTC cell proliferation, migration, and invasion by regulating S1PR2. Overall, the circSSU72/miR-451a/S1PR2 axis might influence PTC cell proliferation, migration, and invasion.

Conclusions: Overall, circSSU72 (hsa_circ_0009294)/miR-451a/S1PR2 axis may promote cell proliferation, migration, and invasion in PTC. Thus, circSSU72 may serve as a potential biomarker and therapeutic target for PTC.

circRPS28 (hsa_circ_0049055) is a novel contributor for papillary thyroid carcinoma by regulating cell growth and motility via functioning as ceRNA for miR-345-5p to regulate frizzled family receptor 8 (FZD8)

Circular RNA 40S ribosomal protein S28 (circRPS28; hsa_circ_0049055) is upregulated in papillary thyroid carcinoma (PTC) patients. However, its role remained uncovered in the progression of PTC. Above all, expression of circRPS28 was determined in PTC samples by real-time quantitative PCR and circRPS28 was highly expressed in tumor tissues and cells. Besides, circRPS28 was predominantly distributed in the cytoplasm. Functional experiments were launched using colony formation assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, 5-ethynyl-2-deoxyuridine (EdU) assay, transwell assays, scratch wound assay, and flow cytometry. As a result, blocking circRPS28 restrained PTC cell viability, EdU positive cell rate, colony formation number, wounding healing rate, and numbers of migration and invasion cells, accompanied with apoptosis rate promotion. These effects paralleled with low B-cell lymphoma (Bcl)-2 level and high Bcl-2-associated X protein (Bax), matrix metalloproteinase-2 (MMP2), and MMP9 levels, as analyzed by western blotting. Overexpressing microRNA (miR)-345-5p exerted similar roles to circRPS28 silencing. Notably, dual-luciferase reporter assay and RNA immunoprecipitation confirmed the target relationship between circRPS28 and miR-345-5p, miR-345-5p and frizzled family receptor 8 (FZD8). Downregulating miR-345-5p abrogated effects of circRPS28 blockage in PTC cells, and restoring FZD8 counteracted miR-345-5p roles, either. Furthermore, xenograft tumor model was established in mice, and exhausting circRPS28 delayed the growth of PTC cells in vivo by regulating miR-345-5p and FZD8. In conclusion, we demonstrated that blocking circRPS28 and/or promoting miR-345-5p suppressed PTC cell growth and motility via regulating FZD8. This study might suggest a novel circRPS28/miR-345-5p/FZD8 competing endogenous RNA pathway in PTC.

The emerging roles of circular RNAs in vessel co-option and vasculogenic mimicry: clinical insights for anti-angiogenic therapy in cancers

Unexpected resistance to anti-angiogenic treatment prompted the investigation of non-angiogenic tumor processes. Vessel co-option (VC) and vasculogenic mimicry (VM) are recognized as primary non-angiogenic mechanisms. In VC, cancer cells utilize pre-existing blood vessels for support, whereas in VM, cancer cells channel and provide blood flow to rapidly growing tumors. Both processes have been implicated in the development of tumor and resistance to anti-angiogenic drugs in many tumor types. The morphology, but rare molecular alterations have been investigated in VC and VM. There is a pressing need to better understand the underlying cellular and molecular mechanisms. Here, we review the emerging circular RNA (circRNA)-mediated regulation of non-angiogenic processes, VC and VM.

Circular RNA Circ_0067934 Attenuates Ferroptosis of Thyroid Cancer Cells by miR-545-3p/SLC7A11 Signaling

Ferroptosis is an emerging programmed cell death distinguished from apoptosis and autophagy and plays essential roles in tumorigenesis. Thyroid cancer is a prevalent endocrine tumor, but the molecular mechanism of ferroptosis during thyroid cancer development remains unclear. Here, we identified the critical function of circular RNA circ_0067934 in repressing ferroptosis of thyroid cancer cells. Our data showed that the ferroptosis activator erastin decreased thyroid cancer cell viabilities, while the circ_0067934 shRNA further attenuated erastin-inhibited cell viabilities. The silencing of circ_0067934 enhanced the levels of ferroptosis-related markers, including Fe2+, iron, and ROS in the cells. The knockdown of circ_0067934 induced thyroid cancer cell apoptosis and repressed thyroid cancer cell proliferation in vitro and in vivo. Circ_0067934 upregulated the expression of the ferroptosis-negative regulator SLC7A11 by sponging and inhibiting miR-545-3p in thyroid cancer cells. The overexpression of SLC7A11 or the inhibitor of miR-545-3p reversed circ_0067934 silencing-regulated thyroid cancer cell proliferation. Therefore, we concluded that Circ_0067934 attenuated ferroptosis of thyroid cancer cells by miR-545-3p/SLC7A11 signaling. Circ_0067934 may serve as a potential therapeutic target by regulating ferroptosis for the treatment of thyroid cancer.

Emerging Roles of Circular RNAs in Thyroid Cancer

Thyroid cancer (TC) has the highest incidence among endocrine malignancies. Thus, it is essential to achieve a deep understanding of various mechanisms of development and progression of TC. circRNAs are recognized by multiple studies as being dysregulated in TC. Accumulating evidences have revealed that circRNAs serve as regulatory molecules involved in various biological processes in TC, including cell proliferation, apoptosis, invasion/migration, metabolism, and chemoresistance. Furthermore, circRNA can also serve as an effective tool in TC researches of diagnosis, prognosis, and treatments. Thus, this review is to outline the characteristics of circRNAs, generalize their categories and functions, and highlight the expression of circRNAs in TC. Meanwhile, we are expecting to achieve a comprehensive understanding of new therapies based on circRNAs in treating or preventing TC.

The emerging function and clinical significance of circRNAs in Thyroid Cancer and Autoimmune Thyroid Diseases

Thyroid cancer (TC) is one of the most common malignant tumors, with high morbidity and mortality rates worldwide. The incidence of TC, especially that of papillary thyroid carcinoma (PTC); has increased rapidly in recent decades. Autoimmune thyroid disease (AITD) is closely related to TC and has an estimated prevalence of 5%. Thus, it is becoming increasingly important to identify potential diagnostic biomarkers and therapeutic targets for TC and AITD. Circular RNAs (circRNAs) are a class of non-coding RNAs with covalently bonded circular structures that lack 5'-3' polarity and polyadenylated tails. Several circRNAs play crucial roles in the development of various diseases, including TC and AITD, and could be important new biomarkers and/or targets for the diagnosis and therapy of such disorders. Although there are four subtypes of TC, research on circRNA has largely focused on its connection to PTC. Therefore, this review mainly summarizes the relationships between circRNAs and PTC and AITD, including the molecular mechanisms underlying these relationships. In particular, the functions of “miRNA sponges” and their interactions with proteins and RNA are discussed. The possible targeting of circRNAs for the prevention, diagnosis, and treatment of TC and AITD is also described. CircRNAs could be potential biomarkers of TC and AITD, although validation will be required before they can be implemented in clinical practice.

circ-PSD3 promoted proliferation and invasion of papillary thyroid cancer cells via regulating the miR-7-5p/METTL7B axis

Papillary thyroid cancer (PTC) is a common tumor malignancy of the endocrine system worldwide. Recently, circular RNAs (circRNAs) have been reported to participate in diverse pathological processes, especially in tumorigenesis. However, the functional role and mechanism of circRNA pleckstrin and Sec7 domain containing 3 (circ-PSD3) in PTC are still unclear. In this study, qRT-PCR results showed that circ-PSD3 was significantly upregulated in PTC tissues and cell lines. Meanwhile, circ-PSD3 overexpression was positively associated with larger tumor size, TNM stage, and lymph node metastasis. Knockdown of circ-PSD3 suppressed the proliferation and invasion of PTC cells. Besides, circ-PSD3 interacted with miR-7-5p to reduce its expression, and methyltransferase like 7B (METTL7B) was verified as a target gene of miR-7-5p. Functionally, inhibition of circ-PSD3 impeded PTC cell proliferation and invasion via targeting miR-7-5p to downregulate METTL7B expression. Taken together, silencing of circ-PSD3 hampered the proliferation and invasion of PTC cells via upregulating the inhibitory effect of miR-7-5p on METTL7B expression. Therefore, circ-PSD3 could be a potential diagnostic biomarker or molecular treatment target for PTC.

Pivotal Role of TGF-β/Smad Signaling in Cardiac Fibrosis: Non-coding RNAs as Effectual Players

Unintended cardiac fibroblast proliferation in many pathophysiological heart conditions, known as cardiac fibrosis, results in pooling of extracellular matrix (ECM) proteins in the heart muscle. Transforming growth factor β (TGF-β) as a pivotal cytokine/growth factor stimulates fibroblasts and hastens ECM production in injured tissues. The TGF-β receptor is a heterodimeric receptor complex on the plasma membrane, made up from TGF-β type I, as well as type II receptors, giving rise to Smad2 and Smad3 transcription factors phosphorylation upon canonical signaling. Phosphorylated Smad2, Smad3, and cytoplasmic Smad4 intercommunicate to transfer the signal to the nucleus, culminating in provoked gene transcription. Additionally, TGF-β receptor complex activation starts up non-canonical signaling that lead to the mitogen-stimulated protein kinase cascade activation, inducing p38, JNK1/2 (c-Jun NH2-terminal kinase 1/2), and ERK1/2 (extracellular signal–regulated kinase 1/2) signaling. TGF-β not only activates fibroblasts and stimulates them to differentiate into myofibroblasts, which produce ECM proteins, but also promotes fibroblast proliferation. Non-coding RNAs (ncRNAs) are important regulators of numerous pathways along with cellular procedures. MicroRNAs and circular long ncRNAs, combined with long ncRNAs, are capable of affecting TGF-β/Smad signaling, leading to cardiac fibrosis. More comprehensive knowledge based on these processes may bring about new diagnostic and therapeutic approaches for different cardiac disorders.

Circular RNAs: New players in thyroid cancer

The prevalence of thyroid cancer the most frequent endocrine malignancy, is rapidly increasing. Most of thyroid cancers are relatively indolent, however, some cases still possess a risk of developing into lethal types of thyroid cancer. Regarding its multistep tumorigenesis, the determination of the underlying mechanisms is a vital issue for thyroid cancer therapy. Circular RNAs (circRNAs) are a type of non-coding RNAs with a closed loop structure. Numerous circRNAs have been identified in cancerous tissues. Mounting data recommends that the biological activities of circRNAs, such as serving as microRNA or ceRNAs sponges, interacting with proteins, modulating gene translation and transcription, suggesting that circRNAs will be potential targets as well as agents for the prognosis and diagnosis of diseases, including cancer. Given that circular RNAs acts as oncogenes or tumor suppressors in the thyroid cancer. Several studies documented that circular RNAs via microRNA and protein sponges could regulate a sequences of cellular and molecular mechanisms e.g., apoptosis, angiogenesis, tumor growth, and invasion that are involved in thyroid cancer pathogenesis. Herein, we summarized the role of circular RNAs as therapeutic and diagnostic biomarkers in the thyroid cancer. Moreover, we highlighted the role of these molecules in the pathogenesis of various cancers.