Salivary transcriptome biomarkers in oral squamous cell cancer detection

A review on trends in development and translation of omics signatures in cancer

The field of cancer genomics and transcriptomics has evolved from targeted profiling to swift sequencing of individual tumor genome and transcriptome. The steady growth in genome, epigenome, and transcriptome datasets on a genome-wide scale has significantly increased our capability in capturing signatures that represent both the intrinsic and extrinsic biological features of tumors. These biological differences can help in precise molecular subtyping of cancer, predicting tumor progression, metastatic potential, and resistance to therapeutic agents. In this review, we summarized the current development of genomic, methylomic, transcriptomic, proteomic and metabolic signatures in the field of cancer research and highlighted their potentials in clinical applications to improve diagnosis, prognosis, and treatment decision in cancer patients.

Salivary Polyamines Help Detect High-Risk Patients with Pancreatic Cancer: A Prospective Validation Study

Pancreatic cancer is one of the most malignant cancer types and has a poor prognosis. It is often diagnosed at an advanced stage because of the absence of typical symptoms. Therefore, it is necessary to establish a screening method for the early detection of pancreatic cancer in high-risk individuals. This is a prospective validation study conducted in a cohort of 1033 Japanese individuals (male, n = 467, age = 63.3 ± 11.5 years; female, n = 566, age = 64.2 ± 10.6 years) to evaluate the use of salivary polyamines for screening pancreatic diseases and cancers. Patients with pancreatic cancer were not included; however, other pancreatic diseases were treated as positive cases for accuracy verification. Of the 135 individuals with elevated salivary polyamine markers, 66 had pancreatic diseases, such as chronic pancreatitis and pancreatic cysts, and 1 had gallbladder cancer. These results suggest that the salivary polyamine panel is a useful noninvasive pancreatic disease screening tool.

Diurnal variations in the expression of core-clock genes correlate with resting muscle properties and predict fluctuations in exercise performance across the day

Objectives

In this study, we investigated daily fluctuations in molecular (gene expression) and physiological (biomechanical muscle properties) features in human peripheral cells and their correlation with exercise performance.

Methods

21 healthy participants (13 men and 8 women) took part in three test series: for the molecular analysis, 15 participants provided hair, blood or saliva time-course sampling for the rhythmicity analysis of core-clock gene expression via RT-PCR. For the exercise tests, 16 participants conducted strength and endurance exercises at different times of the day (9h, 12h, 15h and 18h). Myotonometry was carried out using a digital palpation device (MyotonPRO), five muscles were measured in 11 participants. A computational analysis was performed to relate core-clock gene expression, resting muscle tone and exercise performance.

Results

Core-clock genes show daily fluctuations in expression in all biological samples tested for all participants. Exercise performance peaks in the late afternoon (15–18 hours for both men and women) and shows variations in performance, depending on the type of exercise (eg, strength vs endurance). Muscle tone varies across the day and higher muscle tone correlates with better performance. Molecular daily profiles correlate with daily variation in exercise performance.

Conclusion

Training programmes can profit from these findings to increase efficiency and fine-tune timing of training sessions based on the individual molecular data. Our results can benefit both professional athletes, where a fraction of seconds may allow for a gold medal, and rehabilitation in clinical settings to increase therapy efficacy and reduce recovery times.

Salivary Micro-RNA and Oral Squamous Cell Carcinoma: A Systematic Review

Oral squamous cell carcinoma (OSCC) is a widespread malignancy with high mortality. In particular, a delay in its diagnosis dramatically decreases the survival rate. The aim of this systematic review was to investigate and summarize clinical results in the literature, regarding the potential use of salivary microRNAs (miRNAs) as diagnostic and prognostic biomarkers for OSCC patients. Twelve papers were selected, including both case-control and cohort studies, and all of them detected significantly dysregulated miRNAs in OSCC patients compared to healthy controls. Based on our results, salivary miRNAs might provide a non-invasive and cost-effective method in the diagnosis of OSCC, and also to monitor more easily its evolution and therapeutic response and therefore aid in the establishment of specific therapeutic strategies.

1, 6-O, O-Diacetylbritannilactone from Inula britannica Induces Anti-Tumor Effect on Oral Squamous Cell Carcinoma via miR-1247-3p/LXRα/ABCA1 Signaling

Introduction

Oral squamous cell carcinoma (OSCC) is the most prevalent malignancy affecting the oral cavity and is associated with severe morbidity and high mortality. 1, 6-O, O-Diacetylbritannilactone (OODBL) isolated from the medicinal herb of Inula britannica has various biological activities such as anti-inflammation and anti-cancer. However, the effect of OODBL on OSCC progression remains unclear. Here, we were interested in the function of OODBL in the development of OSCC.

Methods

The effect of OODBL on OSCC progression was analyzed by MTT assays, colony formation assays, transwell assays, apoptosis analysis, cell cycle analysis, and in vivo tumorigenicity analysis. The mechanism investigation was performed by qPCR assays, Western blot analysis, and luciferase reporter gene assays.

Results

We found that OODBL inhibits the proliferation of OSCC cells in vitro. Moreover, the migration and invasion were attenuated by OODBL treatment in the OSCC cells. OODBL arrested cells at the G0/G1 phase and induced cell apoptosis. OODBL was able to up-regulate the expression of LXRα, ABCA1, and ABCG1 in the system. In addition, OODBL activated LXRα/ABCA1 signaling by targeting miR-1247-3p. Furthermore, the expression levels of cytochrome c in the cytoplasm, cleaved caspase-9, and cleaved caspase-3 were dose-dependently reduced by OODBL. Besides, OODBL increased the expression ratio of Bax to Bcl-2. Moreover, OODBL repressed tumor growth of OSCC cells in vivo.

Discussion

Thus, we conclude that OODBL inhibits OSCC progression by modulating miR-1247-3p/LXRα/ABCA1 signaling. Our finding provides new insights into the mechanism by which OODBL exerts potent anti-tumor activity against OSCC. OODBL may be a potential anti-tumor candidate, providing a novel clinical treatment strategy of OSCC.

Transcriptomic analysis of peripheral blood mononuclear cells in head and neck squamous cell carcinoma patients

OBJECTIVES

To investigate the gene expression profile of peripheral blood mononuclear cells (PBMCs) from head and neck squamous cell carcinoma (HNSCC), including oral cancer (OC) and oropharyngeal cancer (OPC) patients, and compare them with healthy controls (HC).

MATERIALS AND METHODS

Transcriptomic analysis of PBMCs was performed by RNA-sequencing. The upregulated candidate genes were selected for validation by quantitative real-time polymerase chain reaction (qPCR). In addition, related plasma protein levels were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Three significantly upregulated genes, including high mobility group nucleosomal binding domain 2 (HMGN2), folate receptor gamma (FOLR3), and amphiregulin (AREG), were selected. In the first cohort, the results showed that only HMGN2 expression was significantly increased in OC patients. In the larger sample size, the overall results demonstrated that HMGN2 expression had a tendency to increase in both OC and OPC patients compared with HC. Interestingly, the plasma HMGN2 (HMG-17) protein level exhibited the same trend as that observed at the transcriptional level.

CONCLUSION

HMGN2 expression and plasma HMG-17 (HMGN2 protein) were increased in both cancer patients compared with HC. This gene may be important for further functional studies in the PBMCs of HNSCC patients.

[Diagnostic accuracy of salivary biomarkers for oral cancer and potentially malignant disorders: A systematic review protocol]

INTRODUCTION

Oral cancer has a 5-year survival rate of 50% because diagnosis is commonly performed at an advanced stage of the disease, so new diagnostic tools are needed. Nowadays, there is a vast number of publications suggesting the use of salivary biomarkers for oral cancer and potentially malignant disorders diagnosis, but their diagnostic accuracy is unclear. Thus, the goal of this systematic review is to evaluate the diagnostic accuracy of salivary biomarkers for oral cancer and potentially malignant disorders.

METHODS

This protocol is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P). We will include primary studies assessing the diagnostic accuracy of salivary biomarkers for oral cancer and potentially malignant disorders. Studies must report data about sensitivity and specificity; gold standard must be the histopathology diagnosis. We will search MEDLINE, EMBASE, the Cochrane Library, and gray literature. Two authors will independently select the studies and extract the data. The methodology quality of studies will be determined using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2).

EXPECTED RESULTS AND CONCLUSION

Our findings will provide information about the diagnostic accuracy of salivary biomarkers for oral cancer and potentially malignant disorders.

A microRNA signature for the differential diagnosis of salivary gland tumors

Salivary gland tumors (SGTs) are rare tumors of the head and neck with different clinical behavior. Preoperative diagnosis, based on instrumental and cytologic examinations, is crucial for their correct management. The identification of molecular markers might improve the accuracy of pre-surgical diagnosis helping to plan the proper treatment especially when a definitive diagnosis based only on cytomorphology cannot be achieved. miRNAs appear to be new promising biomarkers in the diagnosis and prognosis of cancer. Studies concerning the useful of miRNA expression in clinical decision-making regarding SGTs remain limited and controversial.The expression of a panel of 798 miRNAs was investigated using Nanostring technology in 14 patients with malignant SGTs (6 mucoepidermoid carcinomas, 4 adenoid cystic carcinomas, 1 acinic cell carcinoma, 1 ductal carcinoma, 1 cystadenocarcinoma and 1 adenocarcinoma) and in 10 patients with benign SGTs (pleomorphic adenomas). The DNA Intelligent Analysis (DIANA)-miRPath v3.0 software was used to determinate the miRNA regulatory roles and to identify the controlled significant Kyoto Encyclopedia of Genes and Genomes (KEGG) molecular pathways. Forty six miRNAs were differentially expressed (False Discovery Rate—FDR<0.05) between malignant and benign SGTs. DIANA miRPath software revealed enriched pathways involved in cancer processes as well as tumorigenesis, cell proliferation, cell growth and survival, tumor suppressor expression, angiogenesis and tumor progression. Interestingly, clustering analysis showed that this signature of 46 miRNAs is able to differentiate the two analyzed groups. We found a correlation between histological diagnosis (benign or malignant) and miRNA expression profile.The molecular signature identified in this study might become an important preoperative diagnostic tool.

A Noninvasive Test for MicroRNA Expression in Oral Squamous Cell Carcinoma

MicroRNAs have recently been proposed as non-invasive biomarkers in Oral Squamous Cell Carcinoma (OSCC). The aim of this study was to analyze the expression of a panel of miRNAs in epithelial cells collected by oral brushing from OSCCs from regenerative areas after OSCC surgical resection and from their respective normal distant mucosa. Oral brushing specimens were collected from 24 healthy donors, 14 OSCC patients with specimens from tumour and normal distant mucosa, and from 13 patients who had OSCC resection, with samples from regenerative areas after OSCC resection and normal distant mucosa. Expression levels of eight targets (miR-21, miR-375, miR-345, miR-181b, miR-146a, miR-649, miR-518b, and miR-191) were evaluated by real-time Polymerase Chain Reaction (PCR). A highly significant between-group difference was found for miR-21 (F = 6.58, p < 0.001), miR-146a (F = 6.974, p < 0.001), and miR-191 (F = 17.07, p < 0.001). The major difference was observed between samples from healthy donors and from OSCC brushing, whereas no significant differences were observed between areas infiltrated by OSCC and their respective normal distant mucosa. Furthermore, altered expression of miR-146a and miR-191 was also observed in regenerative areas after OSCC resection.

CONCLUSIONS

Oral brushing could be proposed as a noninvasive method to study microRNA expression in oral mucosa in OSCC patients.

More Accurate Oral Cancer Screening with Fewer Salivary Biomarkers

Signal detection and Bayesian inferential tools were applied to salivary biomarkers to improve screening accuracy and efficiency in detecting oral squamous cell carcinoma (OSCC). Potential cancer biomarkers are identified by significant differences in assay concentrations, receiver operating characteristic areas under the curve (AUCs), sensitivity, and specificity. However, the end goal is to report to individual patients their risk of having disease given positive or negative test results. Likelihood ratios (LRs) and Bayes factors (BFs) estimate evidential support and compile biomarker information to optimize screening accuracy. In total, 26 of 77 biomarkers were mentioned as having been tested at least twice in 137 studies and published in 16 summary papers through 2014. Studies represented 10 212 OSCC and 25 645 healthy patients. The measure of biomarker and panel information value was number of biomarkers needed to approximate 100% positive predictive value (PPV). As few as 5 biomarkers could achieve nearly 100% PPV for a disease prevalence of 0.2% when biomarkers were ordered from highest to lowest LR. When sequentially interpreting biomarker tests, high specificity was more important than test sensitivity in achieving rapid convergence toward a high PPV. Biomarkers ranked from highest to lowest LR were more informative and easier to interpret than AUC or Youden index. The proposed method should be applied to more recently published biomarker data to test its screening value.

Salivary miR-93 and miR-200a as post-radiotherapy biomarkers in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma is the 6th most malignant tumor entity worldwide and has exhibited a 5-year mortality of approximately 50% for the last fifty years. For the therapy monitoring and successful management of this tumor entity new and easily accessible biomarkers are greatly needed. The aim of the study was to determine whether and to what extent microRNAs, a class of small regulatory RNAs, are detectable in saliva post-radiation therapy. The expression and feasibility as therapy monitoring marker of the microRNAs were analyzed by RT-qPCR in 83 saliva samples from 33 patients collected at several time points pre-, during and post-radiotherapy treatment. Ten head and neck squamous cell carcinoma- or radiation-associated microRNAs (miR-93, miR-125a, miR-142-3p, miR-200a, miR-203, miR-213, let-7a, let-7b, let-7g and let-7i) were analyzed. All were detectable to a different extent in the saliva of the patients. miR-93 and miR-200a were significantly higher expressed 12 months post-radiotherapy than at baseline (p=0.047 and p=0.036). These results point towards miR-93 and miR-200a as biomarkers for the treatment monitoring post-radiation of head and neck squamous cell carcinoma.

The emerging landscape of salivary diagnostics

Saliva contains a variety of biomolecules, including DNA, coding and noncoding RNA, proteins, metabolites and microbiota. The changes in the salivary levels of these molecular constituents can be used to develop markers for disease detection and risk assessment. Use of saliva as an early-detection tool is a promising approach because collection of saliva is easy and noninvasive. Here, we review recent developments in salivary diagnostics, accomplished using salivaomics approaches, including genomic, transcriptomic, proteomic, metabolomic and microbiomic technologies. Additionally, we illustrate the mechanisms of how diseases distal from the oral cavity can lead to the appearance of discriminatory biomarkers in saliva, and discuss the relevance of these markers for translational and clinical applications.

A versatile method for analysis of saliva, plasma and urine for total thiols using HPLC with UV detection

A simple and rapid HPLC method using 2-chloro-1-methyllepidinium tetrafluoroborate (CMLT) as a derivatization reagent was developed for simultaneous determination of homocysteine (Hcy), glutathione (GSH), γ-glutamylcysteine (γ-GluCys), cysteinylglycine (CysGly), N-acetylcysteine (NACys) and cysteine (Cys) in human saliva, plasma and urine. Separation of the analytes was achieved in just 7min using an HPLC, followed by UV detection at 355nm. Chromatographic separation was accomplished on Aeris PEPTIDE XB-C18 (150mm×4.6mm, 3.6µm) column from Phenomenex with a gradient elution: 0-4.0min, 7-30% B; 4.0-5.5min, 30-7% B; 5.5-7.5min, 7% B; (A: B, v/v); (A) 0.5% CH3COOH and (B) EtOH. Mobile phase was delivered at a flow rate 1.0mLmin(-1). Linearity in detector response for total thiols was observed over the range of 0.1-20μmolL(-1) for Hcy, GSH and γ-GluCys, 0.25-50μmolL(-1) for NACys and CysGly and 5-300 for Cys. The LOQ values for Hcy, GSH, γ-GluCys, NACys, CysGly and Cys were 0.05, 0.05, 0.10, 0.06, 0.12 and 0.08μmolL(-1), respectively. The method was successfully implemented to analysis of the samples donated by 15 apparently healthy volunteers and 10 patients.

The Neonatal Salivary Transcriptome

The ability to noninvasively assess the physical and developmental status of a neonate is a goal of modern medicine. In recent years, technological advances have permitted the high-throughput analysis of saliva for thousands of genes, proteins, and metabolites from a single sample source. Saliva is an ideal biofluid to assess health, disease, and development in the newborn. It may be harnessed repeatedly, even in the most vulnerable patients, without risk of harm. Translating novel information about an infant's global development and risk of disease to the neonatal bedside through the salivary transcriptome has the potential to significantly improve clinical care and outcomes in this at-risk population.

Human Salivary Micro-RNA in Patients with Parotid Salivary Gland Neoplasms

BACKGROUND

Currently, clinical examination, ultrasound scanning (with or without fine needle aspiration cytology), preoperative CT-scan and MRI are available for the differential diagnosis of parotid gland swelling. A preliminary non-invasive salivary diagnostic tool may be helpful in the clinical decision making process. Altered salivary micro-RNA (miRNA) expression levels have been observed in saliva from patients with various cancers. Therefore, we investigated miRNA expression levels in saliva samples from patients with a parotid gland neoplasm using Human miRNA cards in comparison to controls.

RESULTS

In the discovery phase, eight miRNAs were identified having different expression levels in patients compared to controls. In the validation phase, the differences in miRNA expression levels between patients and controls were confirmed for seven out of eight discovered miRNAs (p < 0.001). A combination of two miRNAs yielded a receiver-operator-characteristics curve with an AUC of 0.94 (95% CI: 0.87-1.00; sensitivity 91%; specificity 86%). Validation of discovered miRNAs in segregated collected parotid saliva revealed that expression of these miRNAs differ between whole saliva and parotid saliva.

CONCLUSIONS

A two miRNA combination can predict the presence of a parotid gland neoplasm. Furthermore, this study suggested that the identified, patient-specific, salivary miRNAs were not derived from the parotid gland itself.

Salivary MicroRNA in Pancreatic Cancer Patients

Background

Pancreatic cancer is the fourth leading cause of cancer death in Western countries, with the lowest 1-year survival rate among commonly diagnosed cancers. Reliable biomarkers for pancreatic cancer diagnosis are lacking and are urgently needed to allow for curative surgery. As microRNA (miRNA) recently emerged as candidate biomarkers for this disease, we explored in the present pilot study the differences in salivary microRNA profiles between patients with pancreatic tumors that are not eligible for surgery, precancerous lesions, inflammatory disease or cancer-free patients as a potential early diagnostic tool.

Methods

Whole saliva samples from patients with pancreatic cancer (n = 7), pancreatitis (n = 4), IPMN (n = 2), or healthy controls (n = 4) were obtained during endoscopic examination. After total RNA isolation, expression of 94 candidate miRNAs was screened by q(RT)PCR using Biomark Fluidgm. Human-derived pancreatic cancer cells were xenografted in athymic mice as an experimental model of pancreatic cancer.

Results

We identified hsa-miR-21, hsa-miR-23a, hsa-miR-23b and miR-29c as being significantly upregulated in saliva of pancreatic cancer patients compared to control, showing sensitivities of 71.4%, 85.7%, 85,7% and 57%, respectively and excellent specificity (100%). Interestingly, hsa-miR-23a and hsa-miR23b are overexpressed in the saliva of patients with pancreatic cancer precursor lesions. We found that hsa-miR-210 and let-7c are overexpressed in the saliva of patients with pancreatitis as compared to the control group, with sensitivity of 100% and 75%, and specificity of 100% and 80%, respectively. Last hsa-miR-216 was upregulated in cancer patients as compared to patients diagnosed with pancreatitis, with sensitivity of 50% and specificity of 100%. In experimental models of PDAC, salivary microRNA detection precedes systemic detection of cancer cells markers.

Conclusions

Our novel findings indicate that salivary miRNA are discriminatory in pancreatic cancer patients that are not eligible for surgery. In addition, we demonstrate in experimental models that salivary miRNA detection precedes systemic detection of cancer cells markers. This study stems for the use of salivary miRNA as biomarker for the early diagnosis of patients with unresectable pancreatic cancer.

Comparative performance analyses of commercially available products for salivary collection and nucleic acid processing in the newborn

Analysis of saliva for clinical monitoring and biomarker detection holds great promise for improving health care. Commercially available assays are not intended for use with neonates, however, and collection and processing of saliva for subsequent transcriptomic analysis presents unique challenges in this population. We compared RNA yield, quality, stability and RT-qPCR performance for two commonly used commercial systems: the Qiagen RNeasy Protect Saliva Mini Kit(®) and the DNA Genotek Oragene•RNA(®) assay. Two 10 μl saliva samples were collected from ten newborns and stabilized for each assay. Total RNA was extracted following incubation for 3, 10, 15 or 20 days. Total RNA extracted from each assay was analyzed for integrity, quality and quantity using the Agilent BioAnalyzer 2100. RT-qPCR was performed for the reference gene, GAPDH, to assess subsequent performance of the extracted RNA. Although the DNA Genotek extraction protocol required nearly twice the time of the Qiagen protocol, RNA integrity did not differ between the kits. RNA concentration using the DNA Genotek assay, however, was 3,264 pg/μl (range: 262 - 10,336 pg/μl) compared to 822.4 pg/μl (range: 0 - 1,856 pg/μl) for the Qiagen protocol. Linear regression analysis showed a stronger correlation between the threshold cycle and RNA concentration using DNA Genotek (r(2) = 0.356) compared to Qiagen (r(2) = 0.0331). Our results suggest that although the Qiagen assay may reduce overall extraction time, RNA yield and performance in subsequent transcriptomic analysis is more robust using the DNA Genotek assay.

MicroRNA signatures differentiate Crohn's disease from ulcerative colitis

Background

Excessive and inappropriate immune responses are the hallmark of several autoimmune disorders, including the inflammatory bowel diseases (IBD): Crohn’s disease (CD) and ulcerative colitis (UC). A complex etiology involving both environmental and genetic factors influences IBD pathogenesis. The role of microRNAs (miRNAs), noncoding RNAs involved in regulating numerous biological processes, to IBD pathology, in terms of initiation and progression, remains ill-defined. In the present study, we evaluated the relationship between colon, peripheral blood, and saliva whole miRNome expression in IBD patients and non-inflammatory bowel disease (non-IBD) controls to identify miRNAs that could discriminate CD from UC. Quantitative real-time PCR (qRT-PCR) was used to validate and assess miRNA expression.

Results

Microarray analysis demonstrated that upwards of twenty six miRNAs were changed in CD and UC colon biopsies relative to the non-IBD controls. CD was associated with the differential expression of 10 miRNAs while UC was associated with 6 miRNAs in matched colon tissues. CD was associated with altered expression of 6 miRNAs while UC was associated with 9 miRNAs in whole blood. Expression of miR-101 in CD patients and miR-21, miR-31, miR-142-3p, and miR-142-5p in UC patients were altered in saliva.

Conclusions

Our results suggest that there is specific miRNA expression patterns associated with UC versus CD in three separate tissue/body fluids (colon, blood, and saliva). Further, the aberrant miRNA expression profiles indicate that miRNAs may be contributory to IBD pathogenesis, or at least reflect the underlying inflammation. Scrutinizing miRNA expression in saliva and blood samples may be beneficial in monitoring or diagnosing disease in IBD patients. A panel of miRNAs (miR-19a, miR-21, miR-31, miR-101, miR-146a, and miR-375) may be used as markers to identify and discriminate between CD and UC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-015-0069-0) contains supplementary material, which is available to authorized users.

Detection of tumor cell-specific mRNA and protein in exosome-like microvesicles from blood and saliva

The discovery of disease-specific biomarkers in oral fluids has revealed a new dimension in molecular diagnostics. Recent studies have reported the mechanistic involvement of tumor cells derived mediators, such as exosomes, in the development of saliva-based mRNA biomarkers. To further our understanding of the origins of disease-induced salivary biomarkers, we here evaluated the hypothesis that tumor-shed secretory lipidic vesicles called exosome-like microvesicles (ELMs) that serve as protective carriers of tissue-specific information, mRNAs, and proteins, throughout the vasculature and bodily fluids. RNA content was analyzed in cell free-saliva and ELM-enriched fractions of saliva. Our data confirmed that the majority of extracellular RNAs (exRNAs) in saliva were encapsulated within ELMs. Nude mice implanted with human lung cancer H460 cells expressing hCD63-GFP were used to follow the circulation of tumor cell specific protein and mRNA in the form of ELMs in vivo. We were able to identify human GAPDH mRNA in ELMs of blood and saliva of tumor bearing mice using nested RT-qPCR. ELMs positive for hCD63-GFP were detected in the saliva and blood of tumor bearing mice as well as using electric field-induced release and measurement (EFIRM). Altogether, our results demonstrate that ELMs carry tumor cell-specific mRNA and protein from blood to saliva in a xenografted mouse model of human lung cancer. These results therefore strengthen the link between distal tumor progression and the biomarker discovery of saliva through the ELMs.

The human salivary proteome is radiation responsive

In the event of a nuclear incident in a heavily populated area, the surge in demand for medical evaluation will likely overwhelm our emergency care system, compromising our ability to care for victims with life-threatening injuries or exposures. Therefore, there exists a need for a rapidly deployable biological assay for radiation exposure that can be performed in the field by individuals with little to no medical training. Saliva is an attractive biofluid for this purpose, due to the relative ease of its collection and the wide array of biomolecules it contains. To determine whether the human salivary proteome is responsive to ionizing radiation exposure, we characterized the abundances of salivary proteins in humans before and after total body irradiation. Using an assay panel targeting 90 analytes (growth factors, chemokines and cytokines), we identified proteins that were significantly radiation responsive in human saliva. The responses of three proteins (monocyte chemo-attractant protein 1, interleukin 8 and intercellular adhesion molecule 1) were confirmed using independent immunoassay platforms and then verified and further characterized in 130 saliva samples from a completely independent set of 38 patients undergoing total body irradiation. The results demonstrate the potential for detecting radiation exposure based on analysis of human saliva.

Salivary biomarkers: toward future clinical and diagnostic utilities

The pursuit of timely, cost-effective, accurate, and noninvasive diagnostic methodologies is an endeavor of urgency among clinicians and scientists alike. Detecting pathologies at their earliest stages can significantly affect patient discomfort, prognosis, therapeutic intervention, survival rates, and recurrence. Diagnosis and monitoring often require painful invasive procedures such as biopsies and repeated blood draws, adding undue stress to an already unpleasant experience. The discovery of saliva-based microbial, immunologic, and molecular biomarkers offers unique opportunities to bypass these measures by utilizing oral fluids to evaluate the condition of both healthy and diseased individuals. Here we discuss saliva and its significance as a source of indicators for local, systemic, and infectious disorders. We highlight contemporary innovations and explore recent discoveries that deem saliva a mediator of the body's physiological condition. Additionally, we examine the current state of salivary diagnostics and its associated technologies, future aspirations, and potential as the preferred route of disease detection, monitoring, and prognosis.

Learned and unlearned concepts in periodontal diagnostics: a 50-year perspective

In the past 50 years, conceptual changes in the field of periodontal diagnostics have paralleled those associated with a better scientific understanding of the full spectrum of processes that affect periodontal health and disease. Fifty years ago, concepts regarding the diagnosis of periodontal diseases followed the classical pathology paradigm. It was believed that the two basic forms of destructive periodontal disease were chronic inflammatory periodontitis and 'periodontosis'- a degenerative condition. In the subsequent 25 years it was shown that periodontosis was an infection. By 1987, major new concepts regarding the diagnosis and pathogenesis of periodontitis included: (i) all cases of untreated gingivitis do not inevitably progress to periodontitis; (ii) progression of untreated periodontitis is often episodic; (iii) some sites with untreated periodontitis do not progress; (iv) a rather small population of specific bacteria ('periodontal pathogens') appear to be the main etiologic agents of chronic inflammatory periodontitis; and (v) tissue damage in periodontitis is primarily caused by inflammatory and immunologic host responses to infecting agents. The concepts that were in place by 1987 are still largely intact in 2012. However, in the decades to come, it is likely that new information on the human microbiome will change our current concepts concerning the prevention, diagnosis and treatment of periodontal diseases.

A review of research on salivary biomarkers for oral cancer detection

Using saliva for disease diagnostics and health surveillance is a promising approach as collecting saliva is relatively easy and non-invasive. Over the past two decades, using salivary biomarkers specifically for early cancer detection has attracted much research interest, especially for cancers occurring in the oral cavity and oropharynx, for which the five-year survival rate (62%) is still one of the lowest among all major human cancers. More than 90% of oral cancers are oral squamous cell carcinoma (OSCC) and the standard method for detection is through a comprehensive clinical examination by oral healthcare professionals. Despite the fact that the oral cavity is easily accessible, most OSCCs are not diagnosed until an advanced stage, which is believed to be the major reason for the low survival rate, and points to the urgent need for clinical diagnostic aids for early detection of OSCC. Thus, much research effort has been dedicated to investigating potential salivary biomarkers for OSCC, and more than 100 such biomarkers have been reported in the literature. However, some important issues and challenges have emerged that require solutions and further research in order to find reliable OSCC salivary biomarkers for clinical use. This review article provides an up-to-date list of potential OSCC salivary biomarkers reported as of the fall of 2013, and discusses those emerging issues. By raising the awareness of these issues on the part of both researchers and clinicians, it is hoped that reliable, specific and sensitive salivary biomarkers may be found soon-and not only biomarkers for early OSCC detection but also for detecting other types of cancers or even for monitoring non-cancerous disease activity.

Saliva: a fluid of study for OMICS

Saliva is a fluid that can be collected easily and noninvasively. Its functions in the oral cavity are well known. Advances in molecular biology and technology, as well as research conducted by the various disciplines of omics (genomics, transcriptomics, proteomics, metabolomics, and metagenomics) have contributed to the identification and characterization of salivary components, including DNA, RNA, proteins, metabolites, and microorganisms. These biomolecules enter the saliva through extracellular and intracellular routes, providing information from several organs and systems and raising the possibility of their use as disease biomarkers. In recent years, these factors have expanded the potential use of saliva as a diagnostic fluid for oral and systemic diseases. This review integrates information regarding salivary biomolecules studied through omics and explores their utility as biomarkers for the diagnosis of several infectious and noninfectious diseases, and the opportunity they represent for the development of point of care devices for clinical application. We also discuss the advantages, disadvantages, and challenges to be overcome in order to establish saliva as a useful fluid for the accurate diagnosis and monitoring of a wide range of diseases.

Interleukin-1 beta in unstimulated whole saliva is a potential biomarker for oral squamous cell carcinoma

The objective of this study was to evaluate cytokines in unstimulated whole saliva (UWS) of oral squamous cell carcinoma (OSCC) patients as compared to those with pre- and post-operation for evaluation as markers of OSCC. Sixteen OSCC patients were included in this study. Cytokine concentrations in resting saliva were measured using a Bio-Plex suspension array system. Only interleukin-1 (IL-1) beta showed significantly different cytokine concentration in saliva between pre- and post-operation. IL-1 beta was released from cultured OSCC cells confirmed by ELISA and immunohistochemistry. From this study, IL-1 beta in UWS may be useful for detection of early stage OSCC. More studies are needed to accept the utility of IL-1 beta in UWS for predicting, diagnosis and evaluation of OSCC.

Discovery and prevalidation of salivary extracellular microRNA biomarkers panel for the noninvasive detection of benign and malignant parotid gland tumors

PURPOSE

This study was conducted to explore the differences in salivary microRNA (miRNA) profiles between patients with malignant or benign parotid gland tumors as a potential preoperative diagnostic tool of tumors in the salivary glands.

EXPERIMENTAL DESIGN

Whole saliva samples from patients with malignant (n = 38) or benign (n = 29) parotid gland tumors were obtained from the Salivary Gland Tumor Biorepository (SGTB). After total RNA isolation, human miRNA cards were used for miRNA profiling. The differential miRNA expression was analyzed using two-sided Wilcoxon test. Quantitative real-time PCR (qRT-PCR) was used to validate selected miRNAs in an independent sample set. Receiver-operating characteristics curve and probability of malignancy was exploited to evaluate the diagnostic power of the validated miRNAs.

RESULTS

With miRNA profiling, 57 of 750 investigated miRNAs were differently expressed, of which 54 showed higher miRNA expression in samples from patients with malignant tumors than those from patients with benign tumors. Validating the expression in an independent sample set of 9 miRNAs revealed indeed higher expression of miRNAs in malignant samples compared with benign samples. The expression of 6 validated miRNAs was statistically significantly different between the two groups (P < 0.05). A four miRNA combination was able to discriminate between saliva samples from patients with malignant tumors from those of patients with benign parotid gland tumors (sensitivity 69%, specificity 95%).

CONCLUSIONS

Salivary miRNA profiles differ in saliva from patients with malignant from saliva from patients with a benign parotid gland tumor. These preliminary results are promising to develop a noninvasive diagnostic tool for diagnosing tumors in the salivary glands.

Looking in the mouth for noninvasive gene expression-based methods to detect oral, oropharyngeal, and systemic cancer

Noninvasive diagnosis, whether by sampling body fluids, body scans, or other technique, has the potential to simplify early cancer detection. A classic example is Pap smear screening, which has helped to reduce cervical cancer 75% over the last 50 years. No test is error-free; the real concern is sufficient accuracy combined with ease of use. This paper will discuss methods that measure gene expression or epigenetic markers in oral cells or saliva to diagnose oral and pharyngeal cancers, without requiring surgical biopsy. Evidence for lung and other distal cancer detection is also reviewed.