Assessing miRNAs profile expression as a risk stratification biomarker in oral potentially malignant disorders: A systematic review

Understanding interobserver variability of pathologists to improve oral epithelial dysplasia grading

OBJECTIVE

This study aimed to understand reasons for interobserver variability in the grading of oral epithelial dysplasia (OED) through a survey of pathologists to provide insight for improvements in the reliability and reproducibility of OED diagnoses.

METHODS

The study design included quantitative and qualitative methodology. A pre-validated 31-item questionnaire was distributed to general, head and neck, and oral and maxillofacial histopathology specialists worldwide.

RESULTS

A total of 132 pathologists participated and completed the questionnaire. Over two-thirds used the three-tier grading system for OED, while about a third used both binary and three-tier systems. Regular reporters of OED preferred the three-tier system and grading architectural features. Continuing education significantly aided recognition of architectural and cytological changes. Irregular epithelial stratification and drop-shaped rete ridges had the lowest prognostic value and recognition scores, while loss of epithelial cell cohesion had the highest. Most participants used clinical information and often sought a second opinion when grading OED.

CONCLUSION

Our study has found that frequency of OED reporting and attendance of CME/CPD can play an important role in grading OED. Variations in the prognostic value of individual histological features and the use of clinical information may further contribute to interobserver variability.

A Roadmap for the Rational Use of Biomarkers in Oral Disease Screening

Oral health has witnessed a significant transformation with the integration of biomarkers in early-diagnostic processes. This article briefly reviews the types of biomarkers used in the screening and early detection of oral diseases, particularly oral cancer, periodontal diseases, and dental caries, with an emphasis on molecular biomarkers. While the advent of these biomarkers may represent a leap forward in oral healthcare, it also opens the door to potential overtesting, overdiagnosis, and overtreatment. To inform the selection of novel biomarkers and ensure their rational use in screening tests, it is imperative to consider some key characteristics, which are specific to the biomarker (e.g., surrogate biomarkers should reliably reflect the primary health outcome), to the test (e.g., sensitivity and specificity must be balanced based on the disease of interest), and to the disease (e.g., the efficacy of treatment should improve when the condition is diagnosed earlier). For systemic conditions associated with oral diseases, researchers should be extremely cautious when determining who is "at risk", particularly when such risk is small, non-existent, or inconsequent. This framework aims to ensure that advancements in oral health diagnostics translate into genuine improvements in patient care and well-being.

Histopathological risk assessment in multisite epithelial dysplasia: A meta-analysis

OBJECTIVE

Histopathological grading of oral epithelial dysplasia (OED) is the current standard for stratifying cancer progression risk but is associated with subjectivity and variability. This problem is not commonly seen regarding the grading of epithelial dysplasia in other sites. This systematic review aims to compare grading systems for oral, anal, penile, and cervical epithelial dysplasia to determine their predictive accuracy for recurrence and malignant transformation (MT) outcomes.

METHODS

The review protocol was registered in PROSPERO (CRD42023403035) and was reported according to the PRISMA checklist. A comprehensive search was performed in the main databases and gray literature. The risk of bias in individual studies was analyzed using the Joanna Briggs Institute checklist for each study design.

RESULTS

Forty-six studies were deemed eligible and included in this systematic review, of which 45 were included in the quantitative analysis. Meta-analysis revealed that the binary system demonstrated a higher predictive ability for MT/recurrence of OED compared to multilevel systems. Higher predictive accuracy of MT was also observed for binary grading systems in anal intraepithelial neoplasia.

CONCLUSIONS

No significant difference was found between the current grading systems of epithelial dysplasia in different body parts. However, binary grading systems have shown better clinical outcomes.

Circulating miRNA as a Biomarker in Oral Cancer Liquid Biopsy

Oral cancer is currently challenging the healthcare system, with a high incidence among the population and a poor survival rate. One of the main focuses related to this malignancy is the urge to implement a viable approach for improving its early diagnosis. By introducing the use of liquid biopsy and the identification of potential biomarkers, aiming for a noninvasive approach, new advancements offer promising perspectives in the diagnosis of oral cancer. The present review discusses the potential of circulating miRNAs as oral cancer biomarkers identified in body fluids such as serum, plasma, and saliva samples of oral cancer patients. Existing results reveal an important implication of different miRNA expressions involved in the initiation, development, progression, and metastasis rate of oral malignancy. Liquid biomarkers can play a crucial role in the development of the concept of personalized medicine, providing a wide range of clinical applications and future targeted therapies.

Study of MicroRNA (miR-221-3p, miR-133a-3p, and miR-9-5p) Expressions in Oral Submucous Fibrosis and Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the common types of cancer. Its progression follows a transition from oral potentially malignant disorders (OPMDs) such as oral submucous fibrosis (OSMF). Epigenetic modifiers, especially microRNAs (miRNAs), have an appreciable role in the regulation of various carcinogenic pathways which are being used as biomarkers. miRNAs may also be helpful in the differentiation of oral submucous fibrosis from oral squamous cell carcinoma. Three miRNAs, miR-221-3p, miR133a-3p, and miR-9-5p, were found differentially expressed in many cancers in the literature search supported by our preliminary database search-based screening. The literature and our functional enrichment analysis in an earlier study have reported these miRNAs to regulate carcinogenesis at various steps. In the present study, the expression of these miRNAs was examined in 34 histopathologically confirmed OSCC, 30 OSMF, and 29 control (healthy volunteers) human samples. There was a significant downregulation of miRNA-133a-3p in OSCC compared to OSMF and controls, whereas there was up-regulation in oral submucous fibrosis compared to controls. There was no significant difference in the expression of miR-221-3p between OSCC and OSMF, but an upregulation in OSCC compared to controls. miR-9-5p was also found upregulated in both OSCC and OSMF. Further, miR-133a-3p expression was negatively correlated with age, smoking, drinking status, and AJCC staging, whereas miR-9-5p expression was only positively associated with tobacco/ areca nut chewing. The ROC plots, logistic regression model generated, and the correlation between the expression of miR-9-5p and miR-133a-3p in blood and tissue suggests that these could be used as risk stratification biomarkers.

Identification and Validation of a Potent Multi-lncRNA Molecular Model for Predicting Gastric Cancer Prognosis

Gastric cancer (GC) remains the third deadliest malignancy in China. Despite the current understanding that the long noncoding RNAs (lncRNAs) play a pivotal function in the growth and progression of cancer, their prognostic value in GC remains unclear. Therefore, we aimed to construct a polymolecular prediction model by employing a competing endogenous RNA (ceRNA) network signature obtained by integrated bioinformatics analysis to evaluate patient prognosis in GC. Overall, 1,464 mRNAs, 14,376 lncRNAs, and 73 microRNAs (miRNAs) were found to be differentially expressed in GC. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that these differentially expressed RNAs were mostly enriched in neuroactive ligand–receptor interaction, chemical carcinogenesis, epidermis development, and digestion, which were correlated with GC. A ceRNA network consisting of four lncRNAs, 21 miRNAs, and 12 mRNAs were constructed. We identified four lncRNAs (lnc00473, H19, AC079160.1, and AC093866.1) as prognostic biomarkers, and their levels were quantified by qRT-PCR in cancer and adjacent noncancerous tissue specimens. Univariable and multivariable Cox regression analyses suggested statistically significant differences in age, stage, radiotherapy, and risk score groups, which were independent predictors of prognosis. A risk prediction model was created to test whether lncRNAs could be used as an independent risk predictor of GC or not. These novel lncRNAs’ signature independently predicted overall survival in GC (p < 0.001). Taken together, this study identified a ceRNA and protein–protein interaction networks that significantly affect GC, which could be valuable for GC diagnosis and therapy.

Detection of CAF-1/p60 in peripheral blood as a potential biomarker of HNSCC tumors

To date, a very small number of serum biomarkers have been identified for clinical use in squamous carcinomas of the head and neck region. Chromatin Assembly Factor-1 (CAF-1) heterotrimeric complex subunit CAF1/p60 expression levels have been reported to be of prognostic value in Oral Squamous Cell Carcinoma (OSCC), as well as in other human solid tumors. Here our aim was to detect and quantify CAF1/p60 in the peripheral blood of Head and Neck Squamous Cell Carcinoma (HNSCC) patients, and to investigate the possible associations between serum concentration of CAF-1/p60 and HNSCC tumors. A total of 63 HNSCC patients (51 OSCC, 8 OPSCC, 3 laryngeal SCC, and 1 rhinopharynx SCC) and 30 healthy controls were enrolled. The serum levels of CAF-1/p60 were measured by ELISA assay before and after surgery. Serum CAF-1/p60 concentration resulted significantly higher in cancer patients, compared with healthy controls, in pre-surgery samples (P < 0.05). Serum levels of CAF-1/p60 significantly decreased in serum samples taken after surgery (P < 0.05). Our results demonstrated that CAF-1/p60 may be detected in serum, suggesting a role for CAF-1/p60 as potential soluble biomarkers in HNSCC tumors.

Downregulation of MicroRNA-130a Inhibits Oral Squamous Cell Carcinoma Proliferation and Metastasis via the Hippo-YAP Pathway

Introduction

Oral squamous cell carcinoma (OSCC) means oral epithelial cell injury caused by multiple genetic mutations of the cells. Dysregulation of microRNAs (miRs) can disrupt the progression of OSCC. This study explored the mechanism of miR-130a in OSCC progression.

Methods

miR-130a expression in OSCC cell lines was analyzed. Functional assays were utilized to test the alterations of OSCC cell proliferation, apoptosis and epithelial–mesenchymal transition (EMT) with downregulated miR-130a, shRNA-PTEN or/and YAP inhibitor verteporfin. Then, dual-luciferase reporter gene assay was performed to clarify the targeting relation between miR-130a and PTEN. After that, Hippo-YAP pathway-related protein levels were tested. Moreover, xenograft transplantation was applied to confirm the in vitro experiments.

Results

Highly expressed miR-130a was observed in OSCC cell lines. Silenced miR-130a reduced OSCC proliferation, metastasis, invasion and EMT while propelled apoptosis. Furthermore, miR-130a targeted PTEN to promote the OSCC progression. Downregulation of PTEN reversed the inhibition of silencing miR-130a on proliferation and migration of SCC-4 cells. miR-130a targeted PTEN to inactivate the Hippo-YAP axis. OSCC progression was notably promoted by a combination of YAP inhibitor verteporfin and miR-130a inhibitor. Additionally, silenced miR-130a inhibited OSCC progression in vivo.

Discussion

Silencing miR-130a inhibited OSCC progression by targeting PTEN and activating the Hippo-YAP axis. This investigation may provide novel insight for OSCC treatment.

The relevance of miRNAs as promising biomarkers in lip cancer

OBJECTIVES

This study aimed to analyze the expression of miR-181b, miR-21, miR-31, and miR-345 in actinic cheilitis with and without epithelial dysplasia and lower lip squamous cell carcinomas, and to verify if the deregulated expression of these miRNAs would be indicative of malignant transformation.

MATERIALS AND METHODS

The sample was selected from formalin-fixed paraffin-embedded tissues of 19 actinic cheilitis without epithelial dysplasia, 32 actinic cheilitis with epithelial dysplasia, 42 lower lip squamous cell carcinomas, and 10 nonaltered oral mucosa of the lip. The microRNA (miR, miRNA) expression was quantified by real-time RT-PCR and the expression of the selected miRNAs among the groups of actinic cheilitis and lower lip cancer was compared by chi-square.

RESULTS

A higher expression of miR-181b, miR-31, and miR-345 was found in actinic cheilitis without epithelial dysplasia in comparison to that in actinic cheilitis with epithelial dysplasia and with lower lip cancer. There were no differences in miR-21 expression between actinic cheilitis and lower lip cancer. Hierarchical clustering analysis showed a tendency for a downregulation of miR-181b, miR-21, miR-31, and miR-345 in most patients with lower lip cancers.

CONCLUSIONS

The upregulation of miR-181b, miR-31, and miR-345 expression in actinic cheilitis without epithelial dysplasia and the decrease in the expression of these miRNAs in actinic cheilitis with epithelial dysplasia and in lower lip cancer are potential biomarkers of malignant progression.

CLINICAL RELEVANCE

This miRNA signature can help to identify actinic cheilitis with potential to progress to lip cancer.

Identification of a Transcriptional Prognostic Signature From Five Metabolic Pathways in Oral Squamous Cell Carcinoma

Dysregulated metabolic pathways have been appreciated to be intimately associated with tumorigenesis and patient prognosis. Here, we sought to develop a novel prognostic signature based on metabolic pathways in patients with primary oral squamous cell carcinoma (OSCC). The original RNA-seq data of OSCC from The Cancer Genome Atlas (TCGA) project and Gene Expression Omnibus (GEO) database were transformed into a metabolic pathway enrichment score matrix by single-sample gene set enrichment analysis (ssGSEA). A novel prognostic signature based on metabolic pathways was constructed by LASSO and stepwise Cox regression analysis in the training cohort and validated in both testing and validation cohorts. The optimal cut-off value was obtained using the Youden index by receiver operating characteristic (ROC) curve. The overall survival curves were plotted by the Kaplan-Meier method. A time-dependent ROC curve analysis with 1, 3, 5 years as the defining point was performed to evaluate the predictive value of this prognostic signature. A 5-metabolic pathways prognostic signature (5MPS) for OSCC was constructed which stratified patients into subgroups with favorable or inferior survival. It served as an independent prognostic factor for patient survival and had a satisfactory predictive performance for OSCC. Our results developed a novel prognostic signature based on dysregulated metabolic pathways in OSCC and provided support for aberrant metabolism underlying OSCC tumorigenesis.

MiRNA-128 and MiRNA-142 Regulate Tumorigenesis and EMT in Oral Squamous Cell Carcinoma Through HOXA10

Background

Oral squamous cell carcinoma (OSCC) accounts for more than 90% of all oral cavity cancers, and the 5-year survival rate for OSCC patients remains unsatisfactory. MiRNA-128/miRNA-142 has been reported to work as a tumor suppressor in diverse tumors. However, the biological function of miR-128/miR-142 in OSCC is still unknown.

Methods

The expression of miR-128/miR-142 and homeobox A10 (HOXA10) in OSCC tissues and cells was measured by quantitative real-time polymerase chain reaction (RT-qPCR). The effects of miR-128/miR-142 or HOXA10 on proliferation, migration, invasion and apoptosis were detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), transwell and flow cytometry assays, respectively. The expression levels of epithelial–mesenchymal transition (EMT)-associated proteins (E-cadherin, N-cadherin and Vimentin), proliferation-associated protein ki-67 and HOXA10 were detected by Western blot assay. The interaction between HOXA10 and miR-128/miR-142 was predicted by TargetScan, and then confirmed by dual-luciferase reporter assay.

Results

MiR-128/miR-142 was downregulated in OSCC tissues and cells. Overexpression of miR-128/miR-142 inhibited proliferation, migration, invasion and EMT and induced apoptosis in OSCC cells. HOXA10 as the target of miR-128/miR-142 was verified in OSCC cells. Knockdown of HOXA10 also repressed proliferation, migration, invasion and EMT and boosted apoptosis in OSCC cells. Upregulation of miR-128/miR-142 hindered the expression level of HOXA10, while introduction of HOXA10 weakened the effect.

Conclusion

MiR-128/miR-142 suppressed OSCC tumorigenesis and metastasis by targeting HOXA10, providing a new promising therapeutic approach for OSCC patient diagnosis and treatment.

Comprehensive in silico analysis for identification of novel candidate target genes, including DHX36, OPA1, and SENP2, located on chromosome 3q in head and neck cancers

BACKGROUND

Major milestones of head and neck carcinogenesis have been associated with various genetic abnormalities; however, a clear picture of the molecular networks deregulated during the carcinogenesis of head and neck squamous cell carcinoma (HNSC) has not yet completely revealed.

METHODS

In this study, we used in silico tools and online data sets to evaluate the underlying reasons for the expressional changes of genes residing within the chromosome 3q and to help understanding their contributions to HNSC carcinogenesis.

RESULTS

We found that 13 of 20 most upregulated genes in HNSC are localized to 3q. Further analysis revealed a gene signature consisting of DHX36, OPA1, and SENP2, which showed significant correlation in HNSC samples and potentially be deregulated through similar mechanisms including DNA amplification, transcriptional, and posttranscriptional regulation.

CONCLUSIONS

Considering our findings, we suggest DHX36, OPA1, and SENP2 genes as overexpressed in HNSC tumors and that might be concurrently involved in HNSC carcinogenesis, tumor progression, and induction of angiogenic pathways.

Molecular, genomic and mutational landscape of oral leukoplakia

Oral leukoplakia (OLK) and its more aggressive clinical variant proliferative verrucous leukoplakia (PVL) remain enigmatic disorders clinically and histopathologically. Despite decades of research into both, there has been only incremental advancement in our understanding of their aetiology and pathogenesis and only minimal improvement in effective management strategies. Currently, no specific prognostic genetic or molecular marker has been reported for leukoplakia. There is, however, an emerging body of evidence characterising the genomic and transcriptomic profile of OLK. Regardless of the significance of cellular and architectural features of OLK and PVL, it is clear from studies reported in this review that new emerging evidence points to the presence of premalignant molecular subtypes of leukoplakia which require further investigation. This up-to-date review explores the contemporary genomic, transcriptomic and mutational landscape of leukoplakia broadly, discusses concepts that may not be widely recognised or accepted and purposefully highlights studies with juxtaposed findings in an effort to challenge dogma. It also highlights the urgent need for a concerted international effort of original collaborative research which will only occur by pooling collective efforts, resources and intellect to define the molecular fingerprint of this enigmatic disorder, in the hope it will better inform diagnosis, stratification and treatment.

The roles of microRNAs in the stemness of oral cancer cells

Oral cancer (OC), which is the most common form of head and neck cancers, has one of the lowest (~50%) overall 5-year survival rates. The main reasons for this high mortality rate are diagnosis of OC in advanced stages in most patients and spread to distant organs via lymph node metastasis. Many studies have shown that a small population of cells within the tumor plays vital roles in the initiation, progression, and metastasis of the tumor, resistance to chemotherapeutic agents, and recurrence. These cells, identified as cancer stem cells (CSCs), are the main reasons for the failure of current treatment modalities. Deregulated expressions of microRNAs are closely related to tumor prognosis, metastasis and drug resistance. In addition, microRNAs play important roles in regulating the functions of CSCs. Until now, the roles of microRNAs in the acquisition and maintenance of OC stemness have not been elucidated in detail yet. Here in this review, we summarized significant findings and the latest literature to better understand the involvement of CSCs in association with dysregulated microRNAs in oral carcinogenesis. Possible roles of these microRNAs in acquisition and maintenance of CSCs features during OC pathogenesis were summarized.

Gene Expression Clustering and Selected Head and Neck Cancer Gene Signatures Highlight Risk Probability Differences in Oral Premalignant Lesions

BACKGROUND

Oral premalignant lesions (OPLs) represent the most common oral precancerous conditions. One of the major challenges in this field is the identification of OPLs at higher risk for oral squamous cell cancer (OSCC) development, by discovering molecular pathways deregulated in the early steps of malignant transformation. Analysis of deregulated levels of single genes and pathways has been successfully applied to head and neck squamous cell cancers (HNSCC) and OSCC with prognostic/predictive implications. Exploiting the availability of gene expression profile and clinical follow-up information of a well-characterized cohort of OPL patients, we aim to dissect tissue OPL gene expression to identify molecular clusters/signatures associated with oral cancer free survival (OCFS).

MATERIALS AND METHODS

The gene expression data of 86 OPL patients were challenged with: an HNSCC specific 6 molecular subtypes model (Immune related: HPV related, Defense Response and Immunoreactive; Mesenchymal, Hypoxia and Classical); one OSCC-specific signature (13 genes); two metabolism-related signatures (3 genes and signatures raised from 6 metabolic pathways associated with prognosis in HNSCC and OSCC, respectively); a hypoxia gene signature. The molecular stratification and high versus low expression of the signatures were correlated with OCFS by Kaplan-Meier analyses. The association of gene expression profiles among the tested biological models and clinical covariates was tested through variance partition analysis.

RESULTS

Patients with Mesenchymal, Hypoxia and Classical clusters showed an higher risk of malignant transformation in comparison with immune-related ones (log-rank test, p = 0.0052) and they expressed four enriched hallmarks: "TGF beta signaling" "angiogenesis", "unfolded protein response", "apical junction". Overall, 54 cases entered in the immune related clusters, while the remaining 32 cases belonged to the other clusters. No other signatures showed association with OCFS. Our variance partition analysis proved that clinical and molecular features are able to explain only 21% of gene expression data variability, while the remaining 79% refers to residuals independent of known parameters.

CONCLUSIONS

Applying the existing signatures derived from HNSCC to OPL, we identified only a protective effect for immune-related signatures. Other gene expression profiles derived from overt cancers were not able to identify the risk of malignant transformation, possibly because they are linked to later stages of cancer progression. The availability of a new well-characterized set of OPL patients and further research is needed to improve the identification of adequate prognosticators in OPLs.

DEC1: a potential biomarker of malignant transformation in oral leukoplakia

The purpose of this study was to analyze the differential expression of DEC1 in oral normal mucosa (NM), oral leukoplakia (OLK) and oral squamous cell carcinoma (OSCC). Surgically excised specimens from patients with OLK (n = 47), OSCC (n = 30) and oral normal mucosa (n=11) were immunostained for DEC1. The expression of DEC1 protein was evaluated, and its association with the clinicopathological features was analyzed. The expression of DEC1 in NM, OLK and OSCC tissues increased in turn, and significant differences were observed among the groups (P < 0.0001). In terms of the association between DEC1 expression and epithelial dysplasia, DEC1 expression was lower in hyperkeratosis without dysplasia (H-OLK) than in OLK with moderate to severe dysplasia (S-OLK), and these differences were significant (p < 0.05). The expression of DEC1 in OSCC with OLK was significantly higher than that in OSCC without OLK (p < 0.01). Therefore, DEC1 could be a potential biomarker of malignant transformation in the carcinogenesis of OSCC, which may provide a new research direction for the transformation of oral potentially malignant disorders (OPMDs) into OSCC.

Identification of Candidate Biomarkers and Analysis of Prognostic Values in Oral Squamous Cell Carcinoma

Objectives: Oral squamous cell carcinoma (OSCC) is the most common oral cancer with a poor prognosis owing to limited understanding of the disease mechanisms. The aim of this study was to explore and identify the potential biomarkers in OSCC by integrated bioinformatics analysis.

Materials and Methods: Expression profiles of long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) were downloaded from The Cancer Genome Atlas (TCGA) and differentially expressed RNAs (DERNAs) were subsequently identified in OSCC by bioinformatics analysis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to analyze DERNAs. Then, the competing endogenous RNA (ceRNA) network was constructed in Cytoscape and the protein -protein interaction (PPI) network was established in the STRING database. We established a risk model to predict the overall survival of OSCC on the basis of DElncRNAs with Kaplan–Meier analysis and combined with logrank p test. Furthermore, we identified potential biomarkers by combining univariate Cox regression with overall survival rate, which were then validated in Gene Expression Omnibus (GEO), OSCC cell lines and OSCC specimens.

Results: A total of 1,919 DEmRNAs, 286 DElncRNAs and 111 DEmiRNAs were found to be dysregulated in OSCC. A ceRNA network included 46 DElncRNAs,7 DEmiRNAs and 10 DEmRNAs, and the PPI network included 712 DEmRNAs including 31 hub genes. Moreover, a 7 lncRNAs risk model was established and four genes (CMA1, GNA14, HCG22, HOTTIP) were identified as biomarkers on overall survival in patients with OSCC.

Conclusions: This study successfully constructed a ceRNA network and a PPI network which play a crucial role in OSCC. A risk model was established to predict the prognosis, and four DERNAs are revealed with overall survival in patients with OSCC, suggesting that they may be potential biomarkers in tumor diagnosis and treatment.

miR-31-5p Is a Potential Circulating Biomarker and Therapeutic Target for Oral Cancer

MicroRNAs have been proposed as novel biomarkers for the diagnosis and treatment of many types of cancer. The levels of five candidate microRNAs (miRNAs) (miR-99a-5p, miR-31-5p, miR-138-5p, miR-21-5p, and miR-375-3p) in sera from oral cancer patients and paired tumor and normal tissues were detected by real-time qPCR. The diagnostic power of these miRNAs was analyzed by receiver operating characteristic (ROC) curves. Patient-derived xenograft (PDX) models of oral cancer were established and utilized to verify the potential therapeutic effect of miR-31-5p. Candidate miRNAs were screened from our previous studies and verified in 11 paired oral cancer and adjacent normal tissues. Only serum miR-31-5p levels were significantly different between oral cancer patients and healthy controls and between pre- and postoperative patients. Based on the logistic regression model, this panel of five miRNAs distinguished oral cancer patients from healthy control, with an area under the ROC curve (AUC) of 0.776 (sensitivity = 76.8% and specificity = 73.6%). Furthermore, a miR-31-5p mimic enhanced the proliferation of normal epithelial cells, and antagomiR-31-5p inhibited the proliferation of oral cancer cells in vitro. In vivo, antagomiR-31-5p significantly inhibited tumor growth in oral cancer PDX models. Our findings suggest that circulating miR-31-5p might act as an independent biomarker for oral cancer diagnosis and could serve as a therapeutic target for oral cancer.