Genomewide Study of Salivary MicroRNAs for Detection of Oral Cancer

miRNAs in oral cancer; diagnostic and prognostic roles

Oral cancer (OC) has become increasingly prevalent in recent years, making it one of the most often occurring types of cancer in patients. The clinical identification of OC is usually a time-consuming procedure, and the outlook for individuals with OC is generally unfavorable, as no particular biomarkers have been established to far. The main risk factors linked to OC are high levels of tobacco and alcohol intake, together with a reduced occurrence of viral infections, such as human papillomavirus. Furthermore, there is evidence suggesting that genetic characteristics that can be passed down from parents to offspring play a role in increasing the likelihood of getting ovarian cancer. MicroRNAs (miRNAs) are brief RNA molecules that do not code for proteins and have the ability to either repress or promote the growth of tumors during cancer development. They have been discovered to control multiple signaling pathways within cells, and their abnormal regulation has been demonstrated to be crucial in initiating and furthering the development of cancer. Additionally, they have the ability to either facilitate or impede the entire multi-stage process of cancer metastasis, including epithelial-mesenchymal transition (EMT), migration, and invasion, by selectively targeting essential genes involved in these pathways. Several microRNAs have the ability to regulate gene expression through various ways. In addition, like other types of cancer, OC has shown alterations in the expression of miRNAs, and certain miRNAs may have the ability to be used for diagnosis and treatment. The investigation of these miRNA could perhaps result in advancements in the specified instances of OC.

Protocols for Extraction of miRNA from Extracellular Vesicles of Lyophilized Human Saliva Samples

Extracellular vesicles (EVs) are emerging as crucial biomarkers in molecular diagnostics, providing early detection of disease progression. Although ultracentrifugation remains the gold standard for vesicle isolation from biofluids, it has limitations in scalability and accessibility. This study presents lyophilization as an innovative method for preserving EVs and isolating microRNAs from saliva, utilizing its proven ability to maintain biological activity and prevent unwanted chemical reactions. We assessed five different sample preparation protocols combined with a dual-purification strategy. Structural and molecular integrity analyses revealed that lyophilized samples retained essential EV characteristics, including CD63/CD9 membrane localization. QELS analysis and electron microscopy confirmed distinct vesicle populations in both ultracentrifuged (30-50 nm and 320-360 nm) and lyophilized samples (50-70 nm and 360-380 nm). Importantly, lyophilized samples exhibited higher total RNA concentrations (p < 0.0001) while preserving key microRNA signatures (miR-16, miR-21, miR-33a, and miR-146b) with high fidelity. The efficacy of lyophilization is linked to its ability to systematically reduce solvent content through sublimation while maintaining vesicle integrity and molecular cargo. This method offers a practical, scalable alternative for EV isolation with significant implications for biomarker-based diagnostics.

Decoding Salivary ncRNAomes as Novel Biomarkers for Oral Cancer Detection and Prognosis

Oral cancer (OC) ranks among the most prevalent head and neck cancers, becoming the eleventh most common cancer worldwide with ~350,000 new cases and 177,000 fatalities annually. The rising trend in the occurrence of OC among young individuals and women who do not have tobacco habits is escalating rapidly. Surgical procedures, radiation therapy, and chemotherapy are among the most prevalent treatment options for oral cancer. To achieve better therapy and an early detection of the cancer, it is essential to understand the disease's etiology at the molecular level. Saliva, the most prevalent body fluid obtained non-invasively, holds a collection of distinct non-coding RNA pools (ncRNAomes) that can be assessed as biomarkers for identifying oral cancer. Non-coding signatures, which are transcripts lacking a protein-coding function, have been identified as significant in the progression of various cancers, including oral cancer. This review aims to examine the role of various salivary ncRNAs (microRNA, circular RNA, and lncRNA) associated with disease progression and to explore their functions as potential biomarkers for early disease identification to ensure better survival outcomes for oral cancer patients.

Salivary miRNAs and cytokines associated with diagnosis and prognosis of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common malignant tumour in the oral and maxillofacial region. Early diagnosis can significantly improve the 5-year survival rate of patients with OSCC. Therefore, it is extremely important to differentiate OSCC patients early, easily and quickly. Human saliva contains a variety of components that can be used as biomarkers for the diagnosis and prognosis of OSCC. Studies have shown that salivary microRNAs (miRNAs) and cytokines are closely associated with the progression of OSCC. The aim of this review is to summarize the research progress of salivary biomarkers (miRNAs and cytokines) in the past 3 years, and to explore the possibility of using miRNAs and cytokines to improve the diagnosis and prognosis of OSCC.

Identification of CT based radiomic biomarkers for progression free survival in head and neck squamous cell carcinoma

This study addresses the limited noninvasive tools for Head and Neck Squamous Cell Carcinoma (HNSCC) progression-free survival (PFS) prediction by identifying Computed Tomography (CT)-based biomarkers for predicting prognosis. A retrospective analysis was conducted on data from 203 HNSCC patients. An ensemble feature selection involving correlation analysis, univariate survival analysis, best-subset selection, and the LASSO-Cox algorithm was used to select functional features, which were then used to build final Cox Proportional Hazards models (CPH). Our CPH achieved a 0.69 concordance index in an external indepedent cohort of 77 patients. The model identified five CT-based radiomics features, Gradient ngtdm Contrast, Logσ=33D-FirstorderRootMeanSquared, Logσ=0.13D-glszm SmallAreaLowGrayLevelEmphasis, Exponential-gldm LargeDependenceHighGrayLevelEmphasis, and Gradient ngtdm Strength as survival biomarkers (p-value < 0.05). These findings contribute to our knowledge of how radiomics can be used to predict the outcome so that treatment plans can be tailored for people with HNSCC to improve their prognosis.

Expression of Salivary miRNAs, Clinical, and Demographic Features in the Early Detection of Gastric Cancer: A Statistical and Machine Learning Analysis

OBJECTIVE

Gastric cancer ranks as one of the top five deadliest cancers worldwide and is often diagnosed at late stages. Analysis of saliva may provide a non-invasive approach for detection of malignancies in organs associated with the oral cavity. This research aims to analyze salivary microRNA expression together with clinical and demographic features with the aim of diagnosing gastric cancer.

MATERIALS

The study included 19 patients with early-stage gastric cancer and 19 healthy controls. Saliva samples were collected and processed for RNA isolation. Salivary expression of miR-223-3p and miR-21-5p were measured using quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Receiver operating characteristic (ROC) curves were generated to evaluate the accuracy of diagnostic models. Machine learning algorithms, multiple logistic regression, and principal component analysis (PCA) were used to assess the predictive power of miRNAs in conjunction with clinical-demographic features.

RESULTS

Significant upregulation of miR-223-3p and downregulation of miR-21-5p in saliva were observed in patients with gastric cancer. The area under ROC curve (AUC) values for salivary miR-21-5p, salivary miR-223-3p, and their multiple logistic regression were determined to be 0.723, 0.791, and 0.850, respectively. The AUC for multiple logistic regression model was 0.919. The PCA model led to the highest diagnostic odds ratio (DOR) of 134.33 (sensitivity = 0.785, specificity = 1.00, AUC = 903). Application of machine learning methods, and in particular a random forest algorithm, showed high accuracy in diagnosing patients with gastric cancer (sensitivity = 1.00, specificity = 0.857, AUC = 0.93).

CONCLUSION

The application of validated salivary diagnostics in clinical practice could help facilitate earlier diagnosis of gastric cancer and improve medical outcome. Expression of miR-21 and miR-223-3p in saliva together with clinical and demographic features, appears promising in screening for GC.

Identification of common salivary miRNA in oral lichen planus and oral squamous cell carcinoma: systematic review and meta-analysis

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory condition that can impact patients' quality of life. While its exact etiology remains unclear, it is associated with an increased risk of malignant transformation. Currently, the diagnosis of OLP relies on clinical examination and histopathological analysis, which can be invasive. Therefore, there is an urgent need for non-invasive and accurate diagnostic biomarkers. This systematic review and meta-analysis aims to investigate the potential of salivary microRNAs as promising candidates for OLP diagnosis. This meta-analysis seeks to identify specific microRNAs that are differentially expressed and could serve as reliable biomarkers for OLP diagnosis.

METHODS

Our strategy involved searching for pertinent keywords in multiple academic databases including Cochrane Library, Embase, LIVIVO, MEDLINE, Ovid, ProQuest, Scopus, Web of Science, Espacenet, and Google Scholar search engine. Upon identification, articles were screened and data extracted from the eligible studies. Split component synthesis method was utilized to assess specificity, sensitivity, likelihood and diagnostic odds ratios. The random-effects meta-analysis approach was used to combine study findings and develop pooled diagnostic performance metrics. Hierarchical summary receiver operating characteristic (ROC) plots were generated to determine area under the curve. Subgroup analyses concerning the type of saliva and control groups were also performed.

RESULTS

Among the fourteen studies included in our systematic review, five were eligible for meta-analysis. Salivary microRNAs showed the pooled sensitivity of 0.80 (95% Confidence Interval (95% CI): 0.68-0.88), specificity of 0.89 (95% CI: 0.82-0.94), diagnostic odds ratio of 28.45 (95% CI: 10.40-77.80), and area under the curve (AUC) of 0.93 for OLP diagnosis. Unstimulated saliva had higher sensitivity and specificity than oral swirl samples as the biomarker medium for OLP diagnosis. Meta-analysis uncovered that miR-27a, miR-137, miR-1290, miR-27b, miR-4484, miR-142, and miR-1246 had the highest diagnostic odds ratio for OLP.

CONCLUSIONS

Our systematic review and meta-analysis demonstrate that salivary microRNAs can serve as valuable biomarkers for the diagnosis of OLP. The findings highlight the exceptional accuracy of salivary microRNAs in differentiating OLP patients from healthy controls and assessing the risk of malignant transformation.

Salivary biomarkers in non-invasive oral cancer diagnostics: a comprehensive review

OBJECTIVE

This review aims to provide a comprehensive analysis of the effectiveness of saliva as a non-invasive diagnostic marker for oral cancer. Despite progress in oral cancer diagnosis and prognosis, the 5-year survival rate remains low due to the resistance to treatment and delayed diagnosis, which can be attributed to various factors including tobacco and alcohol consumption, genetic damage, and human papillomavirus (HPV). The potential use of saliva as an easily accessible non-invasive screening and diagnostic method arises from its direct contact with the lesion site.

METHODOLOGY

Data for this study were gathered via a comprehensive literature evaluation using search engines such as the PubMed, Web of Science, Google Scholar, and SciFinder.

RESULTS

Identifying salivary biomarkers shows potential to transform oral cancer diagnostics by offering a reliable alternative to the traditional invasive methods. Saliva is an abundant reservoir for both cell-bound and cell-free organic and inorganic constituents. Thus, saliva is an appropriate field for research in proteomics, genomics, metagenomics, and metabolomics.

CONCLUSION

This review provides a comprehensive elucidation of salivary biomarkers and their function in non-invasive oral cancer diagnosis, demonstrating their potential to enhance patient outcomes and reduce the impact of this devastating disease.

Novel non-invasive molecular signatures for oral cavity cancer, by whole transcriptome and small non-coding RNA sequencing analyses: Predicted association with PI3K/AKT/mTOR pathway

INTRODUCTION

Identification of molecular biomarkers in the saliva and serum of oral cavity cancer patients represents a first step in the development of essential and efficient clinical tools for early detection and post-treatment monitoring. We hypothesized that molecular analyses of paired saliva and serum samples from an individual would likely yield better results than analyses of either serum or saliva alone.

MATERIALS AND METHODS

We performed whole-transcriptome and small non-coding RNA sequencing analyses on 32 samples of saliva and serum collected from the same patients with oral squamous cell carcinoma (OSCC) and healthy controls (HC).

RESULTS

We identified 12 novel saliva and serum miRNAs and a panel of unique miRNA and mRNA signatures, significantly differentially expressed in OSCC patients relative to HC (log2 fold change: 2.6-26.8; DE: 0.02-0.000001). We utilized a combined panel of the 10 top-deregulated miRNAs and mRNAs and evaluated their putative diagnostic potential (>87% sensitivity; 100% specificity), recommending seven of them for further validation. We also identified unique saliva and serum miRNAs associated with OSCC and smoking history (OSCC smokers vs. never-smokers or HC: log2 fold change: 22-23; DE: 0.00003-0.000000001). Functional and pathway analyses indicated interactions between the discovered OSCC-related non-invasive miRNAs and mRNAs and their targets, through PI3K/AKT/mTOR signaling.

CONCLUSION

Our data support our hypothesis that using paired saliva and serum from the same individuals and deep sequencing analyses can provide unique combined mRNA and miRNA signatures associated with canonical pathways that may have a diagnostic advantage relative to saliva or serum alone and may be useful for clinical testing. We believe this data will contribute to effective preventive care by post-treatment monitoring of patients, as well as suggesting potential targets for therapeutic approaches.

Molecular and Therapeutic Roles of Non-Coding RNAs in Oral Cancer-A Review

Oral cancer (OC) is among the most common malignancies in the world. Despite advances in therapy, the worst-case scenario for OC remains metastasis, with a 50% survival rate. Therefore, it is critical to comprehend the pathophysiology of the condition and to create diagnostic and treatment plans for OC. The development of high-throughput genome sequencing has revealed that over 90% of the human genome encodes non-coding transcripts, or transcripts that do not code for any proteins. This paper describes the function of these different kinds of non-coding RNAs (ncRNAs) in OC as well as their intriguing therapeutic potential. The onset and development of OC, as well as treatment resistance, are linked to dysregulated ncRNA expression. These ncRNAs' potentially significant roles in diagnosis and prognosis have been suggested by their differing expression in blood or saliva. We have outlined every promising feature of ncRNAs in the treatment of OC in this study.

Radiomic biomarkers of locoregional recurrence: prognostic insights from oral cavity squamous cell carcinoma preoperative CT scans

Introduction

This study aimed to identify CT-based imaging biomarkers for locoregional recurrence (LR) in Oral Cavity Squamous Cell Carcinoma (OSCC) patients.

Methods

Computed tomography scans were collected from 78 patients with OSCC who underwent surgical treatment at a single medical center. We extracted 1,092 radiomic features from gross tumor volume in each patient's pre-treatment CT. Clinical characteristics were also obtained, including race, sex, age, tobacco and alcohol use, tumor staging, and treatment modality. A feature selection algorithm was used to eliminate the most redundant features, followed by a selection of the best subset of the Logistic regression model (LRM). The best LRM model was determined based on the best prediction accuracy in terms of the area under Receiver operating characteristic curve. Finally, significant radiomic features in the final LRM model were identified as imaging biomarkers.

Results and discussion

Two radiomics biomarkers, Large Dependence Emphasis (LDE) of the Gray Level Dependence Matrix (GLDM) and Long Run Emphasis (LRE) of the Gray Level Run Length Matrix (GLRLM) of the 3D Laplacian of Gaussian (LoG σ=3), have demonstrated the capability to preoperatively distinguish patients with and without LR, exhibiting exceptional testing specificity (1.00) and sensitivity (0.82). The group with LRE > 2.99 showed a 3-year recurrence-free survival rate of 0.81, in contrast to 0.49 for the group with LRE ≤ 2.99. Similarly, the group with LDE > 120 showed a rate of 0.82, compared to 0.49 for the group with LDE ≤ 120. These biomarkers broaden our understanding of using radiomics to predict OSCC progression, enabling personalized treatment plans to enhance patient survival.

The emerging role of liquid biopsy in oral squamous cell carcinoma detection: advantages and challenges

INTRODUCTION

Oral Squamous Cell Carcinoma (OSCC), the sixth most widespread malignancy in the world, accounts for 90% of all cases of oral cancer. The primary risk factors are tobacco chewing, alcohol consumption, viral infection, and genetic modifications. OSCC has a high morbidity rate due to the lack of early diagnostic methods. Nowadays, liquid biopsy plays a vital role in the initial diagnosis of oral cancer. ctNAs extracted from saliva and serum/plasma offer meaningful insights into tumor genetics and dynamics. The interplay of these elements in saliva and serum/plasma showcases their significance in advancing noninvasive, effective OSCC detection and monitoring.

AREAS COVERED

This review mainly focused on the role of liquid biopsy as an emerging point in the diagnosis and prognosis of OSCC and the current advancements and challenges associated with liquid biopsy.

EXPERT OPINION

Liquid biopsy is regarded as a new, minimally invasive, real-time monitoring tool for cancer diagnosis and prognosis. Many biomolecules found in bodily fluids, including ctDNA, ctRNA, CTCs, and EVs, are significant biomarkers to identify cancer in its early stages. Despite these groundbreaking strides, challenges persist. Standardization of sample collection, isolation, processing, and detection methods is imperative for ensuring result reproducibility across diverse studies.

Exosomes: A Cutting-Edge Theranostics Tool for Oral Cancer

Exosomes are a subpopulation of extracellular vesicles (EVs) secreted by cells. In cancer, they are key cellular messengers during cancer development and progression. Tumor-derived exosomes (TEXs) promote cancer progression. In oral cancer, the major complication is oral squamous cell carcinoma (OSCC). Exosomes show strong participation in several OSCC-related activities such as uncontrolled cell growth, immune suppression, angiogenesis, metastasis, and drug and therapeutic resistance. It is also a potential biomarker source for oral cancer. Some therapeutic exosome sources such as stem cells, plants (it is more effective compared to others), and engineered exosomes reduce oral cancer development. This therapeutic approach is effective because of its specificity, biocompatibility, and cell-free therapy (it reduced side effects in cancer treatment). This article highlights exosome-based theranostics signatures in oral cancer, clinical trials, challenges of exosome-based oral cancer research, and future improvements. In the future, exosomes may become an effective and affordable solution for oral cancer.

Salivary miRNAs as auxiliary liquid biopsy biomarkers for diagnosis in patients with oropharyngeal squamous cell carcinoma: a systematic review and meta-analysis

Objective: The healthcare system needs a novel approach to improve and diagnose early oropharyngeal squamous cell carcinoma against its low survival rate. We conduct a systematic review and a comprehensive meta-analysis for the diagnostic role of blood and salivary microRNAs (miRNAs). Methods: An unbiased and thorough literature search in PubMed yielded appropriate data from qualified articles regarding different miRNA biomarkers, method of extraction, research location, and year of publication. Stata was used to calculate the sensitivity, specificity, diagnostic odds ratio, and summary receiver operating characteristic curve. Results: We included 9 studies with 399 qualified oropharyngeal squamous cell carcinoma patients, which yielded a high diagnostic accuracy of blood miRNAs in combination with salivary miRNAs with a sensitivity of 0.70 (p < 0.001), specificity of 0.75 (p = 0.26), diagnostic odds ratio of 7, and an area under the curve of 0.78. Conclusion: Combined blood- and saliva-derived miRNAs demonstrated a high diagnostic accuracy in detecting oropharyngeal squamous cell carcinoma. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024509424.

[Advances in salivary exosomal miRNAs in head and neck squamous carcinoma]

Salivary exosomes are extracellular vesicles of 30-150 nm in diameter that exist in saliva and play an important role in substance exchange and signal transduction between cells, delivering the lipids, proteins and nucleic acids they carry to the recipient cells and regulating the physiological and pathological processes of the recipient cells. miRNA, as an important "cargo" in exosomes, is transported to the recipient cells and regulates the signaling pathways of the recipient cells, thus playing a regulatory role in disease progression. The miRNAs are transported to the recipient cells and regulate the signaling pathways of the recipient cells, thus playing a regulatory role in the progression of diseases. With the development of technological tools this year, numerous studies have revealed the important role of salivary exosomal miRNAs in the development of head and neck squamous carcinoma and the role of salivary exosomal miRNAs in the diagnosis and treatment of head and neck squamous carcinoma. This paper reviews the occurrence, treatment and prognosis of salivary exosomal miRNA in head and neck squamous carcinoma, and discusses the potential prospects and importance of salivary exosomal miRNA as a biomarker in the diagnosis of head and neck squamous carcinoma.

Effect of pre-treatment of melatonin on superovulation response, circulatory hormones, and miRNAs in goats during environmental heat stress conditions

Environmental heat stress has a deleterious impact on farm animal reproductive performance. The purpose of this study was to see how the addition of melatonin affected the efficacy of the superovulation regimen in goats in hot climatic conditions. Sixteen Shiba goats were synchronized and divided into two equal groups (n = 8, each): the melatonin group, which received a single S/C dose of melatonin, and a control group, treated with one ml of corn oil only. Ultrasonographic assessment of ovarian structures (Graafian follicles; GFs and corpus lutea; CLs) morphometry and hemodynamics were performed during the estrous phase of the superovulation (D0) and at day7 after ovulation (D7) of the superovulation regimen. The peripheral reproductive hormones were measured, and microRNAs were characterized. The mean diameter and the total-colored area of GFs during the D0 were significantly (P˂0.05) higher in the melatonin group (5.42 ± 0.11 mm and 1592.20 ± 45.26 pixels, respectively) compared to the control group (4.62 ± 0.12 mm and 1052.55 ± 29.47 pixels, respectively). Concentrations of LH and E2 increased significantly (P˂0.05) in the melatonin group (1.06 ± 0.06 ng/ml and 46.34 ± 2.77 pg/ml, respectively) compared to the control group (0.75 ± 0.12 ng/ml and 29.33 ± 1.89 pg/ml, respectively). At D7, the melatonin-received goats attained greater values in the mean count (6.75 ± 0.33, P˂0.005), diameters (6.08 ± 0.12 mm, P˂0.01), and total-colored area (17137.30 ± 128.53 pixels, P˂0.01) of detected CLs and progesterone concentrations (4.08 ± 0.24 ng/ml) compared to control goats (4.00 ± 0.28, 4.50 ± 0.19 mm, 11156.87 ± 117.90 pixels, and 2.90 ± 0.18 ng/ml respectively). MiRNA expression analysis was identified during both stages denoting several up and downregulated miRNA candidates among the studied groups. In conclusion, incorporating melatonin enhanced the efficiency of the superovulation regimen in goats under hot climatic conditions.

Radiomic Biomarkers of Locoregional Recurrence: Prognostic Insights from Oral Cavity Squamous Cell Carcinoma preoperative CT scans

This study aimed to identify CT-based imaging biomarkers for locoregional recurrence (LR) in Oral Cavity Squamous Cell Carcinoma (OSCC) patients. Our study involved a retrospective review of 78 patients with OSCC who underwent surgical treatment at a single medical center. An approach involving feature selection and statistical model diagnostics was utilized to identify biomarkers. Two radiomics biomarkers, Large Dependence Emphasis (LDE) of the Gray Level Dependence Matrix (GLDM) and Long Run Emphasis (LRE) of the Gray Level Run Length Matrix (GLRLM) of the 3D Laplacian of Gaussian (LoG σ = 3), have demonstrated the capability to preoperatively distinguish patients with and without LR, exhibiting exceptional testing specificity (1.00) and sensitivity (0.82). The group with LRE > 2.99 showed a 3-year recurrence-free survival rate of 0.81, in contrast to 0.49 for the group with LRE ≤ 2.99. Similarly, the group with LDE > 120 showed a rate of 0.82, compared to 0.49 for the group with LDE ≤ 120. These biomarkers broaden our understanding of using radiomics to predict OSCC progression, enabling personalized treatment plans to enhance patient survival.

Stability of circulating miRNA in saliva: The influence of sample associated pre-analytical variables

BACKGROUND AND AIMS

Increasing evidence supports the practicability of salivary cell-free (cf) miRNA as liquid biopsy markers in cancers. Its successful translation in the clinical setting requires reproducible approaches for saliva manipulation, in order to control for pre-analytical variables influencing miRNA stability. This study aims to define the optimal conditions to maintain the integrity of saliva during collection, transport and processing with respect to cf-miRNA quantification.

MATERIALS AND METHODS

Saliva was collected from 20 healthy subjects and 8 oral cancer patients. Two sampling methods were tested and different storage temperatures and times were evaluated. Salivary expression level of target miRNAs was quantified by qPCR. Comparison between group mean values at specific conditions were performed using paired t-tests. Agreement between measurements was evaluated using a Bland-Altman plot.

RESULTS

Different collection methods revealed comparable levels of salivary miR-484 and miR-106b-5p in both subject cohorts. MiRNAs were stable for up to 48 h at 4 °C in saliva supernatant, showing significant alteration after 96 h. Mid-term storage of supernatant at -20 °C decreased miRNA stability significantly compared to standard -80 °C.

CONCLUSIONS

Cf-miRNA in saliva were slightly altered by collection methods and storage conditions, both in healthy and in pathological contexts, and remained stable for a period of time compatible with main clinical routine needs.

Identification of CT-based non-invasive radiomic biomarkers for overall survival prediction in oral cavity squamous cell carcinoma

This study addresses the limited non-invasive tools for Oral Cavity Squamous Cell Carcinoma (OSCC) survival prediction by identifying Computed Tomography (CT)-based biomarkers to improve prognosis prediction. A retrospective analysis was conducted on data from 149 OSCC patients, including CT radiomics and clinical information. An ensemble approach involving correlation analysis, score screening, and the Sparse-L1 algorithm was used to select functional features, which were then used to build Cox Proportional Hazards models (CPH). Our CPH achieved a 0.70 concordance index in testing. The model identified two CT-based radiomics features, Gradient-Neighboring-Gray-Tone-Difference-Matrix-Strength (GNS) and normalized-Wavelet-LLL-Gray-Level-Dependence-Matrix-Large-Dependence-High-Gray-Level-Emphasis (HLE), as well as stage and alcohol usage, as survival biomarkers. The GNS group with values above 14 showed a hazard ratio of 0.12 and a 3-year survival rate of about 90%. Conversely, the GNS group with values less than or equal to 14 had a 49% survival rate. For normalized HLE, the high-end group (HLE > - 0.415) had a hazard ratio of 2.41, resulting in a 3-year survival rate of 70%, while the low-end group (HLE ≤ - 0.415) had a 36% survival rate. These findings contribute to our knowledge of how radiomics can be used to predict the outcome so that treatment plans can be tailored for patients people with OSCC to improve their survival.

Evaluation of Diagnostic Significance of Salivary miRNA-184 and miRNA-21 in Oral Squamous Cell Carcinoma and Oral Potentially Malignant Disorders

BACKGROUND

Altered levels of miRNAs might affect the pathogenesis of oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMD). This study evaluated the diagnostic potential of salivary miRNA-21 and miRNA-184 in OSCC and OPMD.

METHODS

We recruited a total of 90 subjects including OSCC, OPMD, and healthy controls. RNA was isolated from the saliva samples of the study subjects. Expression of miRNA-21 and miRNA-184 was analyzed using qRT-PCR. Their levels were compared and the diagnostic cut-off was determined using the ROC curve.

RESULTS

There was a significant increase in miRNA-21 and a decrease in miRNA-184 in OSCC and OPMD as compared to healthy controls (p < 0.001). Levels of salivary miRNA-21 and miRNA-184 can differentiate OSCC and OPMD from controls and premalignant conditions from malignant conditions.

CONCLUSION

Salivary miRNA-21 and miRNA-184 may be beneficial for the early detection of OSCC and OPMD. Also, saliva can be used for detecting neoplastic transformation of oral mucosa since it is non-invasive and easily accessible.

Emerging cell cycle related non-coding RNA biomarkers from saliva and blood for oral squamous cell carcinoma

The unnotified or undifferentiable early stages of oral squamous cell carcinoma (OSCC) progression are the prime reasons for late-stage detection and poor survival outcomes of oral cancer. This review summarizes the prior research and recent advancements on the influence of dysregulated non-coding RNA (ncRNA) on cell cycle and their employability as diagnostic and prognostic biomarkers of oral cancer. The literature search was performed using the following keywords: 'serum/saliva non-coding RNAs' and 'serum/saliva non-coding RNAs and cell cycle', 'serum/saliva dysregulated ncRNAs and cell cycle', 'Cdk/CKI and ncRNAs', 'tissue ncRNAs' concerning 'oral cancer''. The compiled data focuses mainly on the diagnostic and prognostic significance of MicroRNAs (miRNAs), Circular RNAs (circRNAs), and Long noncoding RNAs (lncRNAs) on oral cancer and all other cancers as well as subject-relevant articles published in languages other than English are beyond the scope of this review and excluded from the study. Moreover, articles focusing on DNA, protein, and metabolite markers are eliminated from the study. While there exist various potential biomolecules such as DNA, RNA, proteins, metabolites, and specific antigens representing predictive biomarkers in body fluids for oral cancer, this review completely focuses on non-coding RNAs restricted to saliva and blood, picking out a few of the reliable ones amongst the recent investigations based on the sophisticated techniques, cohort, and sensitivity as well as specificity, i.e., salivary miR-1307-5p, miR-3928, hsa_circ_0001874 and ENST00000412740, NR_131012, ENST00000588803, NR_038323, miR-21 in circulation. Thus, further studies are required to clinically confirm the usage of these non-invasive biomarkers in oral cancer.

Salivaomics to decode non-coding RNAs in oral cancer. A narrative review

Oral cancer is the most debilitating disease which affects the orderly life of a human. With so much advancement in research and technology, the average life expectancy of an individual with oral cancer appears to be about 5 years. The changing trend in incidence of oral cancer among young individuals and women without tobacco habits are ascending. Non habit related oral cancer are taking centre stage and multiple factors which induce complex biology are associated in such scenarios. To decipher the aetiology and to understand the process, these cancerous conditions are to be studied at molecular level. Saliva, the most non-invasively obtained body fluid are assessed for biomarkers exclusively in liquid biopsy. This fluid gives a huge platform to study number of molecules associated with oral cancer. Non coding RNAs are transcripts with no protein coding function. They are gaining more importance in recent times. Long noncoding RNA, microRNA are major types of noncoding transcriptome that influences in progression of oral cancer. They seem to play an important role in health and disease. Apart from these, circulating tumour cells, exosomes, extracellular vesicles, antigens and other proteins can be studied from saliva. This review is aimed to update the knowledge on current biomarkers in saliva associated with oral cancer and their epigenetic role in disease progression as well recent advances in detecting these markers to identify the stage of the disease, which will help in deciding the treatment protocol.

Identification of CT-based non-invasive Radiographic Biomarkers for Overall Survival Stratification in Oral Cavity Squamous Cell Carcinoma

This study addresses the limited non-invasive tools for Oral Cavity Squamous Cell Carcinoma OSCC survival prediction by identifying Computed Tomography (CT)-based biomarkers for improved prognosis. A retrospective analysis was conducted on data from 149 OSCC patients, including radiomics and clinical. An ensemble approach involving correlation analysis, score screening, and the Sparse-L1 algorithm was used to select functional features, which were then used to build Cox Proportional Hazards models (CPH). Our CPH achieved a 0.70 concordance index in testing. The model identified two CT-based radiomics features, Gradient-Neighboring-Gray-Tone-Difference-Matrix-Strength (GNS) and normalized-Wavelet-LLL-Gray-Level-Dependence-Matrix-Large-Dependence-High-Gray-Level-Emphasis (HLE), as well as smoking and alcohol usage, as survival biomarkers. The GNS group with values above 14 showed a hazard ratio of 0.12 and a 3-year survival rate of about 90%. Conversely, the GNS group with values less than or equal to 14 had a 49% survival rate. For normalized HLE, the high-end group (HLE > -0.415) had a hazard ratio of 2.41, resulting in a 3-year survival rate of 70%, while the low-end group (HLE <= -0.415) had a 36% survival rate. These findings contribute to our knowledge of how radiomics can be used to anticipate the outcome and tailor treatment plans from people with OSCC.

Saliva biomarkers in oral disease

Saliva is a versatile biofluid that contains a wide variety of biomarkers reflecting both physiologic and pathophysiologic states. Saliva collection is noninvasive and highly applicable for tests requiring serial sampling. Furthermore, advances in test accuracy, sensitivity and precision for saliva has improved diagnostic performance as well as the identification of novel markers especially in oral disease processes. These include dental caries, periodontitis, oral squamous cell carcinoma (OSCC) and Sjögren's syndrome (SS). Numerous growth factors, enzymes, interleukins and cytokines have been identified and are the subject of much research investigation. This review highlights current procedures for successful determination of saliva biomarkers including preanalytical factors associated with sampling, storage and pretreatment as well as subsequent analysis. Moreover, it provides an overview of the diagnostic applications of these salivary biomarkers in common oral diseases.

Salivary level of microRNA-146a and microRNA-155 biomarkers in patients with oral lichen planus versus oral squamous cell carcinoma

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa, which has potential for malignant transformation. MicroRNAs play an important role in immunopathogenesis of OLP, and may be used for prediction of its malignant transformation. This study aimed to assess the salivary level of microRNA-146a and microRNA-155 biomarkers in patients with OLP and oral squamous cell carcinoma (OSCC).

METHODS

In this case-control study, unstimulated saliva samples were collected from 60 patients, including 15 patients with dysplastic OLP, 15 OLP patients without dysplasia, 15 patients with OSCC, and 15 healthy controls according to the Navazesh technique. After RNA extraction, the expression of microRNA-146a and microRNA-155 was quantified by real-time quantitative polymerase chain reaction (RT-qPCR). The data were analyzed by the Kruskal-Wallis and Dunn-Bonferroni tests.

RESULTS

The difference in expression of microRNA-146a and microRNA-155 among the four groups was significant (P < 0.05). Pairwise comparisons of the groups showed significantly higher expression of microRNA-146a in OLP (P = 0.004) and dysplastic OLP (P = 0.046) patients compared with the control group. Up-regulation of this biomarker in OSCC patients was not significant compared with the control group (P = 0.076). Up-regulation of micro-RNA-155 was only significant in OLP group, compared with the control group (P = 0.009). No other significant differences were found (P > 0.05).

CONCLUSION

Considering the altered expression of MicroRNA-146a and microRNA-155 in dysplastic OLP and OSCC, their altered expression may serve as an alarming sign of malignancy. However, further investigations are still required.

Role of Vitamin D in Head and Neck Cancer-Immune Function, Anti-Tumour Effect, and Its Impact on Patient Prognosis

Head and neck squamous cell carcinoma (HNSCC) describes a heterogeneous group of human neoplasms of the head and neck with high rates of morbidity and mortality, constituting about 3% of all cancers and ~1.5% of all cancer deaths. HNSCC constituted the seventh most prevalent human malignancy and the most common human cancer in the world in 2020, according to multi-population observations conducted by the GLOBOCAN group. Since approximately 60-70% of patients present with stage III/IV neoplastic disease, HNSCC is still one of the leading causes of death in cancer patients worldwide, with an overall survival rate that is too low, not exceeding 40-60% of these patients. Despite the application of newer surgical techniques and the implementation of modern combined oncological treatment, the disease often follows a fatal course due to frequent nodal metastases and local neoplastic recurrences. The role of micronutrients in the initiation, development, and progression of HNSCC has been the subject of considerable research. Of particular interest has been vitamin D, the pleiotropic biologically active fat-soluble family of secosteroids (vitamin-D-like steroids), which constitutes a key regulator of bone, calcium, and phosphate homeostasis, as well as carcinogenesis and the further development of various neoplasms. Considerable evidence suggests that vitamin D plays a key role in cellular proliferation, angiogenesis, immunity, and cellular metabolism. A number of basic science, clinical, and epidemiological studies indicate that vitamin D has multidirectional biological effects and influences anti-cancer intracellular mechanisms and cancer risk, and that vitamin D dietary supplements have various prophylactic benefits. In the 20th century, it was reported that vitamin D may play various roles in the protection and regulation of normal cellular phenotypes and in cancer prevention and adjunctive therapy in various human neoplasms, including HNSCC, by regulating a number of intracellular mechanisms, including control of tumour cell expansion and differentiation, apoptosis, intercellular interactions, angio- and lymphogenesis, immune function, and tumour invasion. These regulatory properties mainly occur indirectly via epigenetic and transcriptional changes regulating the function of transcription factors, chromatin modifiers, non-coding RNA (ncRNAs), and microRNAs (miRs) through protein-protein interactions and signalling pathways. In this way, calcitriol enhances intercellular communication in cancer biology, restores the connection with the extracellular matrix, and promotes the epithelial phenotype; it thus counteracts the tumour-associated detachment from the extracellular matrix and inhibits the formation of metastases. Furthermore, the confirmation that the vitamin D receptor (VDR) is present in many human tissues confirmed the physiopathological significance of vitamin D in various human tumours. Recent studies indicate quantitative associations between exposure to vitamin D and the incidence of HNC, i.e., cancer risk assessment included circulating calcidiol plasma/serum concentrations, vitamin D intake, the presence of the VDR gene polymorphism, and genes involved in the vitamin D metabolism pathway. Moreover, the chemopreventive efficacy of vitamin D in precancerous lesions of the head and neck and their role as predictors of mortality, survival, and recurrence of head and neck cancer are also widely discussed. As such, it may be considered a promising potential anti-cancer agent for developing innovative methods of targeted therapy. The proposed review discusses in detail the mechanisms regulating the relationship between vitamin D and HNSCC. It also provides an overview of the current literature, including key opinion-forming systematic reviews as well as epidemiological, prospective, longitudinal, cross-sectional, and interventional studies based on in vitro and animal models of HNSCC, all of which are accessible via the PubMed/Medline/EMBASE/Cochrane Library databases. This article presents the data in line with increasing clinical credibility.

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.

The paradigm of miRNA and siRNA influence in Oral-biome

Short nucleotide sequences like miRNA and siRNA have attracted a lot of interest in Oral-biome investigations. miRNA is a small class of non-coding RNA that regulates gene expression to provide effective regulation of post-transcription. On contrary, siRNA is 21-25 nucleotide dsRNA impairing gene function post-transcriptionally through inhibition of mRNA for homologous dependent gene silencing. This review highlights the application of miRNA in oral biome including oral cancer, dental implants, periodontal diseases, gingival fibroblasts, oral submucous fibrosis, radiation-induced oral mucositis, dental Pulp, and oral lichenoid disease. Moreover, we have also discussed the application of siRNA against the aforementioned disease along with the impact of miRNA and siRNA to the various pathways and molecular effectors pertaining to the dental diseases. The influence of upregulation and downregulation of molecular effector post-treatment with miRNA and siRNA and their impact on the clinical setting has been elucidated. Thus, the mentioned details on application of miRNA and siRNA will provide a novel gateway to the scholars to not only mitigate the long-lasting issue in dentistry but also develop new theragnostic approaches.

Induced expression of miR-1250-5p exerts tumor suppressive role in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, and it has a prevalence rate of 15%-20% among all breast cancer cases in younger women. Still, the underlying molecular mechanisms of its pathogenesis are not entirely understood. In the previous study, we identified that microRNA (miR)-1250-5p is significantly down-expressed in TNBC cells. Thus, in the present study, we explore the functional anticancer role of miR-1250-5p in the transient mimic transfected TNBC cells. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to examine the effect of miR-1250-5p on cell viability of TNBC (MDA-MB-231 and MDA-MB-453) cells. The confocal microscopy, quantitative real-time polymerase chain reaction, and western blot analysis techniques were used to assess the effect of miR-1250-5p on cancer hallmarks in test cells. Induced miR-1250-5p expression in MDA-MB-231 and MDA-MB-453 cells decreased cell viability in a time-dependent manner. Increased miR-1250-5p expression levels significantly decreased cell cycle G1/S phase transition markers (Cyclin D1 and CDK4) at messenger RNA (mRNA) and protein levels in TNBC cells compared to scrambled sequence transfected cells. Transient transfection of TNBC cells with miR-1250-5p mimic increased apoptosis in TNBC cells by increasing the level of active caspase (Caspase 8 and Caspase 3) of the intrinsic pathway. Apoptosis-related morphological changes were also observed in the test cells. Further, the induced expression of miR-1250-5p significantly decreased epithelial-mesenchymal transition (EMT) by altering the mRNA and protein levels of E-cadherin and Vimentin. Moreover, results of confocal microscopy revealed increased reactive oxygen species generation, and decreased mitochondria membrane potential in miR-1250-5p mimic transient transfected TNBC cells. In conclusion, miR-1250-5p acts as tumor suppressor in TNBC cells and its induction by therapeutics might be a novel strategy for the disease treatment.

Saliva - a new opportunity for fluid biopsy

Saliva is a complex biological fluid with a variety of biomolecules, such as DNA, RNA, proteins, metabolites and microbiota, which can be used for the screening and diagnosis of many diseases. In addition, saliva has the characteristics of simple collection, non-invasive and convenient storage, which gives it the potential to replace blood as a new main body of fluid biopsy, and it is an excellent biological diagnostic fluid. This review integrates recent studies and summarizes the research contents of salivaomics and the research progress of saliva in early diagnosis of oral and systemic diseases. This review aims to explore the value and prospect of saliva diagnosis in clinical application.

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.

Association of salivary miRNAs with onset and progression of oral potentially malignant disorders: Searching for noninvasive biomarkers

Background/purpose

There is an urgent need for noninvasive biomarkers to diagnose oral potentially malignant disorders (OPMD). A wide range of over 20 miRNAs in saliva of OPMD patients have been investigated in different studies. Yet, which of the ones provide a better power of discrimination for the diagnosis of OPMD onset and progression are uncertain.

Materials and methods

A total of 17 eligible studies including 426 cases of OPMD and 486 control subjects (352 normal mucosa and 134 oral squamous cell carcinoma) were summarized.

Results

The bubble chart analysis showed that the most power salivary miRNA associated with OPMD onset was miR-21, followed by miR-31 and miR-142; the better power miRNAs associated with recurrence and malignant progression of OPMD were miR-31, miR-21, and miR-184.

Conclusion

Salivary miRNAs, especially miR-21 and miR-31, were associated with onset and progression of OPMD, and could then serve as noninvasive biomarkers for screening OPMD and detecting malignant changes.

Salivary miRNAs Expression in Potentially Malignant Disorders of the Oral Mucosa and Oral Squamous Cell Carcinoma: A Pilot Study on miR-21, miR-27b, and miR-181b

(1) Background: Oral potentially malignant disorders (OPMD) represent a fundamental challenge for clinicians, considering the possibility of progression into oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC). Several studies have examined the expression of miRNAs in humans as diagnostic and prognostic biomarkers. Among these, miR-21, miR-27b, and miR-181b proved to be promising. This cohort study evaluated the different expressions of those miRNAs in the saliva of patients with OPMD and OSCC. (2) Methods: Patients with a clinical diagnosis of OPMD and/or OSCC were enrolled; saliva samples were collected; miRNAs were extracted and quantified via qRT-PCR was performed. Data were analyzed by subgroups based on the histopathological diagnosis (OSCC and the grade of OED) using the ΔΔCt method. Saliva from 10 healthy donors was used as the control. One-way ANOVA and Kruskal-Wallis tests were performed to assess the differences between groups. (3) Results: 23 patients for the OPMD group (6 with no dysplasia, 7 with low-grade, and 10 with high-grade dysplasia) and 10 with OSCC were analyzed. MiR-21 did not show any variation among groups; miR-27b was under-expressed in dysplastic lesions (p = 0.046); miR-181b was upregulated in high-grade dysplasia (p = 0.006), increasing with the degree of dysplasia, and decreasing in OSCCs. (4) Conclusions: Salivary miR-27b and miR-181b could be promising biomarkers for oral dysplasia. Further studies are needed to clarify their feasibility.

Liquid biopsy in the assessment of microRNAs in oral squamous cell carcinoma: A systematic review

Background

The identification of non-invasive biomarkers from biological fluids collected by liquid biopsy provides new horizons for individualized therapeutic strategies and improves clinical decision-making in OSCC patients. Circulating microRNAs have emerged as biomarkers that may reflect not only the existence of cancer, but also the dynamic, malignant potential, and drug resistance of tumors. The aim of the systematic review is to evaluate and summarize the results of the published studies regarding the use of microRNAs as biomarkers for OSCC.

Material and Methods

A literature search was conducted on PubMed, Scopus, Web of Science, and Cochrane databases till November 2020. A total of 34 studies met the inclusion criteria and were therefore subjected to quality assessment. Each study was subjected to data extraction including; patient characteristics, type of fluid sample (whole blood, plasma, serum, or saliva), molecular analysis method, specific dysregulated microRNA, and microRNA expression pattern.

Results

The analysis showed that 57 microRNAs of liquid biopsy samples of four different fluids (whole blood, serum, plasma, and saliva) were analyzed. The prognostic and therapeutic significance of these microRNAs were suggested by several studies; where 41 microRNAs were upregulated while 16 were downregulated.

Conclusions

Scientific evidence supports the interest in the use of microRNAs in the diagnosis and prognosis in OSCC patients; however, further studies in a larger cohort of patients are mandatory to introduce liquid biopsy in the routine clinical practice for the OSCC management. Key words:Biomarkers, liquid biopsy, microRNA, oral squamous cell carcinoma, systematic review.

Current Status, Opportunities, and Challenges of Exosomes in Oral Cancer Diagnosis and Treatment

Oral cancer is one of the most common cancers in the world, with more than 300,000 cases diagnosed each year, of which oral squamous cell carcinoma accounts for more than 90%, with a 5-year survival rate of only 40–60%, and poor prognosis. Exploring new strategies for the early diagnosis and treatment of oral cancer is key to improving the survival rate. Exosomes are nanoscale lipid bilayer membrane vesicles that are secreted by almost all cell types. During the development of oral cancer, exosomes can transport their contents (DNA, RNA, proteins, etc) to target cells and promote or inhibit the proliferation, invasion, and metastasis of oral cancer cells by influencing the host immune response, drug-resistant metastasis, and tumour angiogenesis. Therefore, exosomes have great potential and advantages as biomarkers for oral cancer diagnosis, and as drug delivery vehicles or targets for oral cancer therapy. In this review, we first describe the biogenesis, biological functions, and isolation methods of exosomes, followed by their relationship with oral cancer. Here, we focused on the potential of exosomes as oral cancer biomarkers, drug carriers, and therapeutic targets. Finally, we provide an insightful discussion of the opportunities and challenges of exosome application in oral cancer diagnosis and treatment, intending to offer new ideas for the clinical management of oral cancer.

Research progress and clinical application prospects of miRNAs in oral cancer

Oral cancer is one of the most common malignant tumors worldwide, and it is also one of the most important and difficult clinical problems to be solved. Due to the regional differences in diet culture, some areas have taken the 'hardest hit' of oral cancer cases. However, the existing clinical treatment methods (surgery as the main treatment method, radiotherapy and chemotherapy as the auxiliary ones) do not have satisfactory treatment effects; therefore, new diagnosis and treatment methods need to be developed and utilized. Micro RNAs (miRNAs), as a class of substances that play an important regulatory role in the development of tumors, have an important value in the diagnosis and treatment of various tumors. At the same time, many miRNAs have obvious expression differences in oral cancer tissues compared to normal tissues. Therefore, they may have diagnostic and therapeutic effects on oral cancer. In this review, we evaluate the miRNAs that play a regulatory role in the development of oral cancer and those that are expected to be applied in the diagnosis and treatment of oral cancer. At the same time, we summarize the important challenges that need to be addressed, aiming to provide evidence and suggestions for the application of miRNAs in the diagnosis and treatment of oral cancer.

Saliva Diagnostics

Cancer remains one of the leading causes of death, and early detection of this disease is crucial for increasing survival rates. Although cancer can be diagnosed following tissue biopsy, the biopsy procedure is invasive; liquid biopsy provides an alternative that is more comfortable for the patient. While blood, urine, and cerebral spinal fluid can all be used as a source of liquid biopsy, saliva is an ideal source of body fluid that is readily available and easily collected in the most noninvasive manner. Characterization of salivary constituents in the disease setting provides critical data for understanding pathophysiology and the evaluation of diagnostic potential. The aim of saliva diagnostics is therefore to develop a rapid and noninvasive detection of oral and systemic diseases that could be used together with compact analysis systems in the clinic to facilitate point-of-care diagnostics.

Current Scientific Research Trends on Salivary Biomarkers: A Bibliometric Analysis

Salivary biomarkers are indicators of many biological and pathological conditions and provide further information regarding the early detection of diseases. This bibliometric analysis aims to identify and evaluate the scientific literature addressing salivary biomarkers from a dental perspective, to identify the most prolific organizations, authors, journals, countries, and keywords used within this research domain. An electronic search was performed using Elsevier’s Scopus database. From a total of 587 retrieved papers (published between 1997 and 2021), 399 were selected. For the data analysis and its visualization, the title of the articles, year of publication, countries, authors, journals, articles, and keywords were analyzed using Microsoft Excel and VOSviewer (a bibliometric software program). An increase in the number of publications was identified from 1997 to 2021. The United States (U.S.) published the most papers (84) and received the highest citations (3778), followed by India and Brazil. The Journal of Periodontology published the highest number of articles (39) that received the highest citations. The University of Kentucky from the U.S. published most of the papers related to salivary biomarkers that received the highest citations. Timo Sorsa published the most papers (14 papers), while Craig Miller was the highest cited author (754 citations). Concerning the highly cited papers, a paper by Micheal et al., published in 2010, received the highest citations (487 citations). “Saliva”, followed by “human”, were the most common keywords used by the authors in the papers related to salivary biomarkers. The findings of this analysis revealed an increase in salivary biomarker-related publications that positively influenced the number of citations each paper received. The U.S. produced the most publications that received the highest citations, and the University of Kentucky, U.S., was the most prominent. The articles were mostly published in the Journal of Periodontology and received the highest number of citations.

The expression of salivary microRNAs in oral lichen planus: Searching for a prognostic biomarker

Oral lichen planus (OLP) is a premalignant disease with unknown etiology. It has been demonstrated that inflammation and immune activation play a central role in the pathogenesis of OLP. Various cellular and molecular mechanisms are involved in the pathogenesis of OLP. Studies have shown that 2-7% of OLP patients develop oral squamous cell carcinoma (OSCC). As a result, determining the prognosis of the disease will be promising in preventing oral carcinoma. MicroRNAs are involved in the regulation of cytokine expression and cytokines have a central role in the pathogenesis of OLP. As a result, their evaluation in body fluids may be helpful in assessing the disease's status and progression, and facilitating the treatment process. In this regard, much attention has been paid to the saliva of OLP patients as the sampling is cost-effective and non-invasive. Here, we discuss the potential of miRNAs in predicting the disease severity and progression.

Saliva Based Liquid Biopsies in Head and Neck Cancer: How Far Are We From the Clinic?

Head and neck cancer (HNC) remains to be a major cause of mortality worldwide because of confounding factors such as late-stage tumor diagnosis, loco-regional aggressiveness and distant metastasis. The current standardized diagnostic regime for HNC is tissue biopsy which fails to determine the thorough tumor dynamics. Therefore, due to the ease of collection, recent studies have focused on the utility of saliva based liquid biopsy approach for serial sampling, early diagnosis, prognosis, longitudinal monitoring of disease progression and treatment response in HNC patients. Saliva collection is convenient, non-invasive, and pain-free and offers repetitive sampling along with real time monitoring of the disease. Moreover, the detection, isolation and analysis of tumor-derived components such as Circulating Tumor Nucleic Acids (CTNAs), Extracellular Vesicles (EVs), Circulating Tumor Cells (CTCs) and metabolites from saliva can be used for genomic and proteomic examination of HNC patients. Although, these circulatory biomarkers have a wide range of applications in clinical settings, no validated data has yet been established for their usage in clinical practice for HNC. Improvements in isolation and detection technologies and next-generation sequencing analysis have resolved many technological hurdles, allowing a wide range of saliva based liquid biopsy application in clinical backgrounds. Thus, in this review, we discussed the rationality of saliva as plausible biofluid and clinical sample for diagnosis, prognosis and therapeutics of HNC. We have described the molecular components of saliva that could mirror the disease status, recent outcomes of salivaomics associated with HNC and current technologies which have the potential to improve the clinical value of saliva in HNC.

Exploiting salivary miR-375 as a clinical biomarker of oral potentially malignant disorder

Background/purpose

Oral potentially malignant disorder (OPMD) is an important premalignancy worldwide. MicroRNAs (miRNAs) are endogenously expressed non-coding RNAs that regulate the post-transcriptional levels of targeted mRNAs. MiRNA-375 (miR-375) is markedly downregulated in oral carcinoma tissues and plays an oncogenic role in oral carcinogenesis. We explored the potential of the deregulated salivary miR-375 levels in OPMD patients.

Materials and methods

. We analyzed the levels of miR-375 in the saliva of patients with OPMD (n = 45) and healthy controls (n = 24) by quantitative RT-PCR. The cell lysates and supernatants were treated with the miR-375 mimic and inhibitor.

Results

Salivary miR-375 levels were decreased markedly in the patients with OPMD, compared with the controls. OPMD patients with non-dysplasia showed a higher abundance of miR-375 in the saliva than dysplasia patients, suggesting that salivary miR-375 is a more sensitive marker for OPMD. Patients with malignant transformation during the follow-up period showed lower expression of saliva miR-375 than the others. MiR-375 expression was markedly decreased by treatment with the miR-375 inhibitor, and the supernatants of both NHOK and SAS cells showed a corresponding decline in miR-375 expression.

Conclusion

Our results indicate the potential application of salivary miR-375 as a biomarker for the detection and long-term follow-up of OPMD.

A Systematic Review of Oral Biopsies, Sample Types, and Detection Techniques Applied in Relation to Oral Cancer Detection

Background: Early identification of the stage of oral cancer development can lead to better treatment outcomes and avoid malignant transformation. Therefore, this review aims to provide a comprehensive overview that describes the development of standardized procedures for oral sample collection, characterization, and molecular risk assessment. This can help investigators to choose the appropriate sampling method and downstream analyses for different purposes. Methods: This systematic review was conducted according to the PRISMA guidelines. Using both PubMed and Web of Science databases, four independent authors conducted a literature search between 15 and 21 June 2021. We used key search terms to broaden the search for studies. Non-conforming articles were removed using an EndNote-based and manual approach. Reviewers used a designed form to extract data. Results: This review included a total of 3574 records, after eliminating duplicate articles and excluding papers that did not meet the inclusion criteria. Finally, 202 articles were included in this review. We summarized the sampling methods, biopsy samples, and downstream analysis. The biopsy techniques were classified into tissue and liquid biopsy. The common sequential analysis of tissue biopsy includes histopathological examination such as H&E or IHC to identify various pathogenic features. Meanwhile, liquid samples such as saliva, blood, and urine are analyzed for the purpose of screening to detect mutations in cancer. Commonly used technologies are PCR, RT-PCR, high-throughput sequencing, and metabolomic analysis. Conclusions: Currently, tissue biopsies provide increased diagnostic value compared to liquid biopsy. However, the minimal invasiveness and convenience of liquid biopsy make it a suitable method for mass screening and eventual clinical adoption. The analysis of samples includes histological and molecular analysis. Metabolite analysis is rising but remains scarce.

A microRNA Signature Identifies Patients at Risk of Barrett Esophagus Progression to Dysplasia and Cancer

BACKGROUND

Progression of Barrett esophagus (BE) to esophageal adenocarcinoma occurs among a minority of BE patients. To date, BE behavior cannot be predicted on the basis of histologic features.

AIMS

We compared BE samples that did not develop dysplasia or carcinoma upon follow-up of ≥ 7 years (BE nonprogressed [BEN]) with BE samples that developed carcinoma upon follow-up of 3 to 4 years (BE progressed [BEP]).

METHODS

The NanoString nCounter miRNA assay was used to profile 24 biopsy samples of BE, including 13 BENs and 11 BEPs. Fifteen samples were randomly selected for miRNA prediction model training; nine were randomly selected for miRNA validation.

RESULTS

Unpaired t tests with Welch's correction were performed on 800 measured miRNAs to identify the most differentially expressed miRNAs for cases of BEN and BEP. The top 12 miRNAs (P < .003) were selected for principal component analyses: miR-1278, miR-1301, miR-1304-5p, miR-517b-3p, miR-584-5p, miR-599, miR-103a-3p, miR-1197, miR-1256, miR-509-3-5p, miR-544b, miR-802. The 12-miRNA signature was first self-validated on the training dataset, resulting in 7 out of the 7 BEP samples being classified as BEP (100% sensitivity) and 7 out of the 8 BEN samples being classified as BEN (87.5% specificity). Upon validation, 4 out of the 4 BEP samples were classified as BEP (100% sensitivity) and 4 out of the 5 BEN samples were classified as BEN (80% specificity). Twenty-four samples were evaluated, and 22 cases were correctly classified. Overall accuracy was 91.67%.

CONCLUSION

Using miRNA profiling, we have identified a 12-miRNA signature able to reliably differentiate cases of BEN from BEP.

Liquid Biopsy as a Tool for the Characterisation and Early Detection of the Field Cancerization Effect in Patients with Oral Cavity Carcinoma

Oral squamous cell carcinoma (OSCC) constitutes approximately 25% of all head and neck cancer, for which the consumption of tobacco and alcohol are the main associated risk factors. The field cancerization effect of OSCC is one of the main reasons for the poor survival rates associated with this disease. Despite some advances, its ccharacterization and early diagnosis continue to challenge modern oncology, and the goal of improving the prognosis remains to be achieved. Among new early diagnostic tools for OSCC that have been proposed, liquid biopsy appears to be an ideal candidate, as studies have shown that the analysis of blood and saliva provides promising data for the early detection of relapses or second tumours.

Upregulation of CPNE7 in mesenchymal stromal cells promotes oral squamous cell carcinoma metastasis through the NF-κB pathway

A remarkable shift in Mesenchymal stromal cells (MSCs) plays an important role in cancer metastasis, but the molecular mechanism is still unclear. CPNE7, a calcium-dependent phospholipid-binding protein, mediates signal transduction and metastasis in many tumours. Here, we demonstrated that MSCs derived from OSCC (OSCC-MSCs) promoted the metastasis of OSCC cells by transwell assay and animal models through epithelial to mesenchymal transition (EMT) (p < 0.05). RNA-sequencing, ELISA, neutralizing antibody and CXCR2 inhibitor assay confirmed that CXCL8 secreted by OSCC-MSCs was associated with the upregulated expression of CPNE7 by immunohistochemical and western blotting (p < 0.05). This is mechanistically linked to the activation of CPNE7 to NF-κB pathway-induced metastasis, including phosphorylated p65 and IκBa. CPNE7 silencing inhibited metastatic abilities and the expression of CXCL8, phosphorylated p65, IκBa, and p65 nuclear translocation by western blotting and immunofluorescence, while CPNE7 overexpression markedly promoted these events (p < 0.05). We also identified that Nucleolin could be bind CPNE7 and IκBa by co-immunoprecipitation. Together, our results suggest that upregulation of CPNE7 in MSCs interacted with surface receptor -Nucleolin and then combined with IκBa to promoted phosphorylated IκBa and p65 nuclear translocation to active NF-κB pathway, and then regulates CXCL8 secretion to promote the metastasis of OSCC cells. Therefore, CPNE7 in MSCs could be promising therapeutic targets in OSCC.

MiR-200c-3p expression may be associated with worsening of the clinical course of patients with COVID-19

COVID-19 represents a public health emergency, whose mechanism of which is not fully understood. It is speculated that microRNAs may play a crucial role in host cells after infection by SARS-CoV-2. Thus, our study aimed to analyze the expression of miR-200c-3p in saliva samples from patients with COVID-19. One handred eleven samples from patients with COVID-19 were divided into 4 groups. Group I: 39 patients negative for Covid-19; Group II: 37 positive and symptomatic patients, with no indication of hospitalization; Group III: 21 patients with respiratory disorders (hospitalized); Group IV: 14 patients with severe conditions (oxygen therapy). The expression levels of miR-200c-3p were determined using qPCR. We found greater expression of miR-200c-3p in patients in group IV (p<0.0001), and also verified that patients aged ≥42 years had a higher expression of this miR (p=0.013). Logistic regression analysis revealed that the expression of miR-200c-3p and systemic arterial hypertension are factors independently associated with patients in group IV (p<0.0001). Our results suggest that miR-200c-3p is a predictor of severity independent of COVID-19 risk factors, which could represent a way of screening patients affected by SARS-CoV-2.