Diagnosis of lung cancer in individuals with solitary pulmonary nodules by plasma microRNA biomarkers

Decreased levels of circulating sex hormones as a biomarker of lung cancer in male patients with solitary pulmonary nodules

BACKGROUND

An early differentiation of malignant from benign solitary pulmonary nodules (SPNs) is essential for management and prognosis of lung cancer.

OBJECTIVES

Here we investigated whether measurement of circulating sex hormones could be useful for an early detection of malignancy among patients with SPNs.

METHODS

We recruited 47 patients with malignant SPNs 45 patients with benign SPNs, and 32 healthy persons. Testosterone, estradiol, and progesterone were measured. Carcinoembryonic antigen (CEA) as well as TNF-α, IL-1 and IL-6 were also measured.

RESULTS

We found that sex hormones were decreased significantly in patients with malignant SPNs, as compared to patients with benign SPNs and healthy controls (P<0.05). Sex hormones levels showed a trend to decline in patients with benign SPNs as compared to normal controls, but the difference was not statistically significant (P>0.05). CEA levels were only abnormally elevated in eight patients with lung adenocarcinoma. The inflammatory cytokines were remarkably higher in both patients than in normal controls. However, there was no statistical difference in these cytokines among patients.

CONCLUSIONS

The reduced sex hormones levels seemed to be uniquely associated with lung cancer. Therefore, measurement of sex hormones may have clinical potential in the diagnosis of malignancy in patients with SPNs.

Characterization of microRNA transcriptome in lung cancer by next-generation deep sequencing

Non-small cell lung cancer (NSCLC) is the leading cause of cancer death. Systematically characterizing miRNAs in NSCLC will help develop biomarkers for its diagnosis and subclassification, and identify therapeutic targets for the treatment. We used next-generation deep sequencing to comprehensively characterize miRNA profiles in eight lung tumor tissues consisting of two major types of NSCLC, squamous cell carcinoma (SCC) and adenocarcinoma (AC). We used quantitative PCR (qPCR) to verify the findings in 40 pairs of stage I NSCLC tissues and the paired normal tissues, and 60 NSCLC tissues of different types and stages. We also investigated the function of identified miRNAs in lung tumorigenesis. Deep sequencing identified 896 known miRNAs and 14 novel miRNAs, of which, 24 miRNAs displayed dysregulation with fold change ≥4.5 in either stage I ACs or SCCs or both relative to normal tissues. qPCR validation showed that 14 of 24 miRNAs exhibited consistent changes with deep sequencing data. Seven miRNAs displayed distinctive expressions between SCC and AC, from which, a panel of four miRNAs (miRs-944, 205-3p, 135a-5p, and 577) was identified that cold differentiate SCC from AC with 93.3% sensitivity and 86.7% specificity. Manipulation of miR-944 expression in NSCLC cells affected cell growth, proliferation, and invasion by targeting a tumor suppressor, SOCS4. Evaluating miR-944 in 52 formalin-fixed paraffin-embedded SCC tissues revealed that miR-944 expression was associated with lymph node metastasis. This study presents the earliest use of deep sequencing for profiling miRNAs in lung tumor specimens. The identified miRNA signatures may provide biomarkers for early detection, subclassification, and predicting metastasis, and potential therapeutic targets of NSCLC.

Development and validation of clinical diagnostic models for the probability of malignancy in solitary pulmonary nodules

BACKGROUND

It is critical to develop a non-invasive and accurate method for differentiating between malignant and benign solitary pulmonary nodules. In large sample studies, the effectiveness of the diagnostic prediction model as a tool of assessment of the probability of malignancy is still unclear. The establishment of a diagnostic model based on large samples is needed.

METHODS

In this study, 3358 patients diagnosed with a solitary pulmonary nodule between January 2005 and March 2013, were enrolled. All patients received surgery for pulmonary nodule resection. Clinical characters, preoperative biomarker results, and computed tomography scan findings were collected. All patients were randomly separated into a training set (n = 1679) and a test set (n = 1679); we used training sets to build a diagnostic model for the malignancy probability of pulmonary nodules, and applied the test set to validate our model, as well as other published diagnostic models.

RESULT

Logistic regression analysis identified 11 clinical characteristics as independent predictors of malignancy in patients with a solitary pulmonary nodule. The goodness-of-fit statistic for the model indicated that the observed proportion of malignancies did not differ from the predicted proportion (P = 0.571). The area under the curves of the receiver operator characteristic curve for our model in the training set was 0.935.

CONCLUSION

As the accuracy of the model was high, we suggest that the diagnostic model can be used as a tool to help guiding clinical decisions, when the clinician cannot make a definitive diagnosis of a solitary pulmonary nodule.

Distinguishing patients with stage I lung cancer versus control individuals using serum mass profiling

Serum mass profiling can discern physiological changes associated with specific disease states and their progression. Sera (86 total) from control individuals and patients with stage I nonsmall cell lung cancer or benign small pulmonary nodules were discriminated retrospectively by serum changes discerned by mass profiling. Control individuals were distinguished from patients with Stage I lung cancer or benign nodules with test sensitivities of 89% and 83%. Lung cancer patients versus those with benign nodules were distinguished with 80% sensitivity. This study exhibits progress toward a minimally-invasive aid in early detection of lung cancer and monitoring small pulmonary nodules for malignancy.

Serum miR-499 as a novel diagnostic and prognostic biomarker in non-small cell lung cancer

The aim of the present study was to determine whether serum miR-499 may be used as a biomarker for early detection of non-small cell lung cancer (NSCLC). The present study was designed as an initial screening phase and a subsequent validation phase. In the screening phase, we analyzed serum levels of miR-499 in a subset of 40 patients with stage I (n=20) and stage IV (n=20) NSCLC. In the validation phase, miR-499 expression levels in serum (n=514) and tissue (n=136) from NSCLC patients were detected in a large and independent cohort of 514 patients. miR-499 in the screening phase was found to be significantly elevated in the serum of stage I NSCLC patients compared with that in stage IV NSCLC patients (P<0.001). Validation analysis showed that serum miR-499 levels were robust in differentiating NSCLC patients from control subjects [area under the curve (AUC)=0.906; 95% confidence interval (CI)=0.879 to 0.929). Serum miR-499 levels were significantly lower in stage III and IV patients compared with those with stage I (both P<0.001) or II (both P<0.001). Low serum miR-499 levels were associated with shorter overall survival and served as an independent prognostic biomarker in NSCLC patients [hazard ratio (HR)=1.63; 95% CI=1.33-2.0; P<0.0001). In addition, low serum levels of miR-499 indicated a poor disease-free survival in stage I-II NSCLC patients. Serum miR-499 may prove to be a promising biomarker for early detection and prognosis prediction of NSCLC.

Methodological challenges in utilizing miRNAs as circulating biomarkers

MicroRNAs (miRNAs) have emerged as important regulators in the post-transcriptional control of gene expression. The discovery of their presence not only in tissues but also in extratissular fluids, including blood, urine and cerebro-spinal fluid, together with their changes in expression in various pathological conditions, has implicated these extracellular miRNAs as informative biomarkers of disease. However, exploiting miRNAs in this capacity requires methodological rigour. Here, we report several key procedural aspects of miRNA isolation from plasma and serum, as exemplified by research in cardiovascular and pulmonary diseases. We also highlight the advantages and disadvantages of various profiling methods to determine the expression levels of plasma- and serum-derived miRNAs. Attention to such methodological details is critical, as circulating miRNAs become diagnostic tools for various human diseases.

Tumor-associated circulating microRNAs as biomarkers of cancer

MicroRNAs (miRNAs), the 17- to 25-nucleotide long noncoding RNAs that modulate the expression of mRNAs and proteins, have emerged as critical players in cancer initiation and progression processes. Deregulation of tissue miRNA expression levels associated with specific genetic alterations has been demonstrated in cancer, where miRNAs function either as oncogenes or as tumor-suppressor genes and are shed from cancer cells into circulation. The present review summarizes and evaluates recent advances in our understanding of the characteristics of tumor tissue miRNAs, circulating miRNAs, and the stability of miRNAs in tissues and their varying expression profiles in circulating tumor cells, and body fluids including blood plasma. These advances in knowledge have led to intense efforts towards discovery and validation of differentially expressing tumor-associated miRNAs as biomarkers and therapeutic targets of cancer. The development of tumor-specific miRNA signatures as cancer biomarkers detectable in malignant cells and body fluids should help with early detection and more effective therapeutic intervention for individual patients.

Clinical relevance of circulating cell-free microRNAs in cancer

Efficient patient management relies on early diagnosis of disease and monitoring of treatment. In this regard, much effort has been made to find informative, blood-based biomarkers for patients with cancer. Owing to their attributes-which are specifically modulated by the tumour-circulating cell-free microRNAs found in the peripheral blood of patients with cancer may provide insights into the biology of the tumour and the effects of therapeutic interventions. Moreover, the role of microRNAs in the regulation of different cellular processes points to their clinical utility as blood-based biomarkers and future therapeutic targets. MicroRNAs are optimal biomarkers owing to high stability under storage and handling conditions and their presence in blood, urine and other body fluids. In particular, detection of levels of microRNAs in blood plasma and serum has the potential for an earlier cancer diagnosis and to predict prognosis and response to therapy. This Review article considers the latest developments in the use of circulating microRNAs as prognostic and predictive biomarkers and discusses their utility in personalized medicine.

Digital PCR quantification of miRNAs in sputum for diagnosis of lung cancer

PURPOSE

MicroRNAs (miRNAs) play important roles in the initiation and progression of lung cancer. Measuring miRNA expression levels in sputum could provide a potential approach for the diagnosis of lung cancer. The emerging digital PCR is a straightforward technique for precise, direct, and absolute quantification of nucleic acids. The objective of the study was to investigate whether digital PCR could be used to quantify miRNAs in sputum for lung cancer diagnosis.

METHODS

We first determined and compared dynamic ranges of digital PCR and conventional quantitative reverse transcriptase PCR (qRT-PCR) for miRNA quantification using RNA isolated from sputum of five healthy individuals. We then used digital PCR to quantify copy number of two lung cancer-associated miRNAs (miR-31 and miR-210) in 35 lung cancer patients and 40 cancer-free controls.

RESULTS

Copy number of the miRNAs measured by digital PCR displayed a linear response to input cDNA amount in a twofold dilution series over seven orders of magnitude. miRNA quantification determined by digital PCR assay was in good agreement with that obtained from qRT-PCR analysis in sputum. Furthermore, combined quantification of miR-31 and miR-210 copy number by using digital PCR in sputum of the cases and controls provided 65.71 % sensitivity and 85.00 % specificity for lung cancer diagnosis.

CONCLUSION

As digital PCR becomes more established, it would be a robust tool for quantitative assessment of miRNA copy number in sputum for lung cancer diagnosis.

Quantification of Plasma miRNAs by Digital PCR for Cancer Diagnosis

Analysis of plasma microRNAs (miRNAs) by quantitative polymerase chain reaction (qPCR) provides a potential approach for cancer diagnosis. However, absolutely quantifying low abundant plasma miRNAs is challenging with qPCR. Digital PCR offers a unique means for assessment of nucleic acids presenting at low levels in plasma. This study aimed to evaluate the efficacy of digital PCR for quantification of plasma miRNAs and the potential utility of this technique for cancer diagnosis. We used digital PCR to quantify the copy number of plasma microRNA-21-5p (miR-21–5p) and microRNA-335–3p (miR-335–3p) in 36 lung cancer patients and 38 controls. Digital PCR showed a high degree of linearity and quantitative correlation with miRNAs in a dynamic range from 1 to 10,000 copies/μL of input, with high reproducibility. qPCR exhibited a dynamic range from 100 to 1×10⁷ copies/μL of input. Digital PCR had a higher sensitivity to detect copy number of the miRNAs compared with qPCR. In plasma, digital PCR could detect copy number of both miR-21–5p and miR-335–3p, whereas qPCR was only able to assess miR-21–5p. Quantification of the plasma miRNAs by digital PCR provided 71.8% sensitivity and 80.6% specificity in distinguishing lung cancer patients from cancer-free subjects.

Detection of extracellular RNAs in cancer and viral infection via tethered cationic lipoplex nanoparticles containing molecular beacons

Noninvasive early detection methods have the potential to reduce mortality rates of both cancer and infectious diseases. Here, we present a novel assay by which tethered cationic lipoplex nanoparticles containing molecular beacons (MBs) can capture cancer cell-derived exosomes or viruses and identify encapsulated RNAs in a single step. A series of ultracentrifugation and Exoquick isolation kit were first used to isolate exosomes from the cell culture medium and human serum, respectively. Cationic lipoplex nanoparticles linked onto the surface of a thin glass plate capture negatively charged viruses or cell-secreted exosomes by electrostatic interactions to form larger nanoscale complexes. Lipoplex/virus or lipoplex/exosome fusion leads to the mixing of viral/exosomal RNAs and MBs within the lipoplexes. After the target RNAs specially bind to the MBs, exosomes enriched in target RNAs are readily identified by the fluorescence signals of MBs. The in situ detection of target extracellular RNAs without diluting the samples leads to high detection sensitivity not achievable by existing methods, e.g., quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Here we demonstrate this concept using lentivirus and serum from lung cancer patients.

Novel and convenient method to evaluate the character of solitary pulmonary nodule-comparison of three mathematical prediction models and further stratification of risk factors

Objective

To study risk factors that affect the evaluation of malignancy in patients with solitary pulmonary nodules (SPN) and verify different predictive models for malignant probability of SPN.

Methods

Retrospectively analyzed 107 cases of SPN with definite post-operative histological diagnosis whom underwent surgical procedures in China-Japan Friendship Hospital from November of 2010 to February of 2013. Age, gender, smoking history, malignancy history of patients, imaging features of the nodule including maximum diameter, position, spiculation, lobulation, calcification and serum level of CEA and Cyfra21-1 were assessed as potential risk factors. Univariate analysis model was used to establish statistical correlation between risk factors and post-operative histological diagnosis. Receiver operating characteristic (ROC) curves were drawn using different predictive models for malignant probability of SPN to get areas under the curves (AUC values), sensitivity, specificity, positive predictive values, negative predictive values for each model, respectively. The predictive effectiveness of each model was statistically assessed subsequently.

Results

In 107 patients, 78 cases were malignant (72.9%), 29 cases were benign (27.1%). Statistical significant difference was found between benign and malignant group in age, maximum diameter, serum level of Cyfra21-1, spiculation, lobulation and calcification of the nodules. The AUC values were 0.786±0.053 (Mayo model), 0.682±0.060 (VA model) and 0.810±0.051 (Peking University People’s Hospital model), respectively.

Conclusions

Serum level of Cyfra21-1, patient’s age, maximum diameter of the nodule, spiculation, lobulation and calcification of the nodule are independent risk factors associated with the malignant probability of SPN. Peking University People’s Hospital model is of high accuracy and clinical value for patients with SPN. Adding serum index (e.g. Cyfra21-1) into the prediction models as a new risk factor and adjusting the weight of age in the models might improve the accuracy of prediction for SPN.

Diagnostic and prognostic value of circulating miR-21 for cancer: a systematic review and meta-analysis

BACKGROUND

MicroRNAs (miRNAs) have been reported to be aberrantly expressed in patients with cancer. Many studies have shown that circulating miRNAs could play potential roles as diagnostic and prognostic biomarkers of cancers. The aim of this meta-analysis is to summarize the role of circulating miR-21 as a biomarker in patients with a variety of carcinomas.

MATERIAL AND METHODS

Eligible studies were identified and assessed for quality through multiple search strategies. For diagnostic meta-analysis, the sensitivity, specificity, and other measures of miR-21 in the diagnosis of cancer were pooled using bivariate random-effects approach models. For prognostic meta-analysis, pooled hazard ratios (HRs) of circulating miR-21 for survival were calculated.

RESULTS

A total of 36 studies dealing with various carcinomas were included for the systemic review. Among them, 23 studies were finally enrolled in the global meta-analysis (17 studies for diagnosis and 6 studies for prognosis). For diagnostic meta-analysis, the overall pooled results for sensitivity, specificity, positive likelihood ratio (LRP), negative likelihood ratios (LRN) and diagnostic odds ratio (DOR) were 75.7% (95% CI: 67.1%-82.6%), 79.3% (95% CI: 74.2%-83.5%), 3.65 (95% CI: 2.83-4.70), 0.31 (95% CI: 0.22-0.43), and 11.88 (95% CI: 6.99-20.19), respectively. For prognostic meta-analysis, the pooled HR of higher miR-21 expression in circulation was 2.37 (95% CI: 1.83-3.06, P<0.001), which could significantly predict poorer survival in general carcinomas. Importantly, subgroup analysis suggested that higher expression of miR-21 correlated with worse overall survival (OS) significantly in carcinomas of digestion system (HR, 5.77 [95% CI: 2.65-12.52]).

CONCLUSIONS

Our findings suggest that circulating miR-21 may not suitable to be a diagnostic biomarker, but it has a prognostic value in patients with cancer.

MicroRNAs in body fluids as biomarkers for non-small cell lung cancer: a systematic review

Non-small cell lung cancer (NSCLC) is one of the most common life-threatening malignant tumors. A test for early diagnosis of NSCLC needs to be not too invasive and not too heavy a burden for weakened patients. A series of studies reported various microRNAs (miRNAs) could be novel serum biomarkers for NSCLC. However, the diagnostic ability of different miRNA biomarkers varies among the reports. The goal of this study was to perform a systematic review to examine the effect of miRNAs on NSCLC-related outcomes. We systematically searched The Cochrane Central Register of Controlled Trials, MEDLINE, Pub Med, EMBASE, the Chinese Biomedical Literature Database, the China Academic Journals Full-text Database, and the Chinese Scientific Journals Database for potential studies. Studies were included if they were related to miRNAs, NSCLC, and reported diagnostic outcomes. Diagnostic values analysis was used to summarize the overall test performance of miRNAs. 13 studies were included in this systematic review. The ranges of sensitivity (SEN) and specificity (SPE) of diagnosis model with miRNAs as identifying NSCLC were 0.69˜1.00 and 0.66˜1.00, respectively. The overall area under the curve (AUC) value of summary receiver operating characteristic (SROC) curve was 0.9151. The ranges of positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 2.33˜24.75 and 0.010.40, respectively. The range of diagnostic odds ratio (DOR) was 6.52˜983.38. The current evidence indicates that miRNAs in body fluids show high accuracy in identifying NSCLC, and could be a useful screening tool for diagnosing NSCLC patients.

[Diagnosis and management of solitary pulmonary nodules]

目前，肺癌已跃居成为我国发病率及死亡率最高的恶性肿瘤，总体5年生存率较低；早诊早治是提高肺癌患者生存率及改善预后的关键，而早期肺癌患者常无任何症状和体征，只在影像学上表现为肺孤立性结节病变。提高对孤立性肺结节良恶性的鉴别诊断能力是临床诊治过程中的难点与热点。随着各种诊治技术的发展，孤立性肺结节病变性质的诊断准确率已大大提高。

MicroRNA-210 overexpression predicts poorer prognosis in glioma patients

MicroRNA-210 (miR-210) levels are elevated in many tumor types, are frequently associated with hypoxia induction, and are correlated with poor prognosis in many solid tumors. miR-210 regulates cell growth, angiogenesis, invasion, and apoptosis of many human tumors. In this study, we investigated the clinical significance of miR-210 expression in common brain tumors, or human gliomas. Glioma samples and normal brain tissues were analyzed using real-time quantitative reverse transcriptase polymerase chain reaction to characterize the expression patterns of miR-210. The association of miR-210 expression with clinicopathological parameters and prognosis of glioma patients was statistically analyzed. Gliomas were further divided by grade: pilocytic astrocytoma (World Health Organization [WHO] grade I), diffuse astrocytomas (WHO grade II), anaplastic astrocytomas (WHO grade III), and glioblastoma (WHO grade IV). There was a significantly higher expression level of miR-210 amongst the glioma tissues as compared with normal brain tissues (p<0.001). Increased expression of miR-210 in glioma tissues was significantly associated with advanced pathological grade (p<0.001) and low Karnofsky Performance Score (p=0.014). In addition, increased miR-210 levels were also associated with poor progression-free survival (PFS) and overall survival (OS) rates when compared to the normal control (both p<0.001), as calculated by Kaplan-Meier survival and Cox regression analyses. Furthermore, subgroup analyses showed that miR-210 expression was significantly associated with poor PFS and OS of glioma patients with high pathological grades (III-IV: both p<0.001). miR-210 is highly expressed in human gliomas and confers a poor prognosis in glioma patients. These findings may bring the development of novel, tailored pharmacological therapies for glioma patients.

Global analysis of serum microRNAs as potential biomarkers for lung adenocarcinoma

Early diagnosis and the ability to predict the most relevant treatment option for individuals is essential to improve clinical outcomes for non-small cell lung cancer (NSCLC) patients. Adenocarcinoma (ADC), a subtype of NSCLC, is the single biggest cancer killer and therefore an urgent need to identify minimally invasive biomarkers to enable early diagnosis. Recent studies, by ourselves and others, indicate that circulating miRNAs have potential as biomarkers. Here we applied global profiling approaches in serum from patients with ADC of the lung to explore if miRNAs have potential as diagnostic biomarkers. This study involved RNA isolation from 80 sera specimens including those from ADC patients (equal numbers of stages 1, 2, 3, and 4) and age- and gender-matched controls (n = 40 each). Six hundred and sixty-seven miRNAs were co-analyzed in these specimens using TaqMan low density arrays and qPCR validation using individual miRNAs. Overall, approximately 390 and 370 miRNAs were detected in ADC and control sera, respectively. A group of 6 miRNAs, miR-30c-1* (AUC = 0.74; P<0.002), miR-616* (AUC = 0.71; P = 0.001), miR-146b-3p (AUC = 0.82; P<0.0001), miR-566 (AUC = 0.80; P<0.0001), miR-550 (AUC = 0.72; P = 0.0006), and miR-939 (AUC = 0.82; P<0.0001) was found to be present at substantially higher levels in ADC compared with control sera. Conversely, miR-339-5p and miR-656 were detected at substantially lower levels in ADC sera (co-analysis resulting in AUC = 0.6; P = 0.02). Differences in miRNA profile identified support circulating miRNAs having potential as diagnostic biomarkers for ADC. More extensive studies of ADC and control serum specimens are warranted to independently validate the potential clinical relevance of these miRNAs as minimally invasive biomarkers for ADC.

Insulin growth factor signaling is regulated by microRNA-486, an underexpressed microRNA in lung cancer

MicroRNAs (miRNAs) are small 19- to 24-nt noncoding RNAs that have the capacity to regulate fundamental biological processes essential for cancer initiation and progression. In cancer, miRNAs may function as oncogenes or tumor suppressors. Here, we conducted global profiling for miRNAs in a cohort of stage 1 nonsmall cell lung cancers (n = 81) and determined that miR-486 was the most down-regulated miRNA in tumors compared with adjacent uninvolved lung tissues, suggesting that miR-486 loss may be important in lung cancer development. We report that miR-486 directly targets components of insulin growth factor (IGF) signaling including insulin-like growth factor 1 (IGF1), IGF1 receptor (IGF1R), and phosphoinositide-3-kinase, regulatory subunit 1 (alpha) (PIK3R1, or p85a) and functions as a potent tumor suppressor of lung cancer both in vitro and in vivo. Our findings support the role for miR-486 loss in lung cancer and suggest a potential biological link to p53.

Identification of circulating microRNAs as biomarkers in cancers: what have we got?

During the past few years there has been great interest in the development of circulating microRNAs (miRNAs) as stable blood-based biomarkers for cancer detection. Deregulation of miRNAs in blood samples has shown considerable clinical utilities in cancers. Due to poorly characterized preanalytical and analytical variables and the lack of a standardized measurement protocol, the application of these miRNA fingerprints is hindered by conflicting results. In this review,we outline our current understanding of preanalytically and analytically confounding factors. We believe that great consideration should be taken in the development of circulating miRNA as tumor biomarkers.

Metabolic profiling of plasma from benign and malignant pulmonary nodules patients using mass spectrometry-based metabolomics

Solitary pulmonary nodule (SPN or coin lesion) is a mass in the lung and can be commonly found in chest X-rays or computerized tomography (CT) scans. However, despite the advancement of imaging technologies, it is still difficult to distinguish malignant cancer from benign SPNs. Here we investigated the metabolic profiling of patients with benign and malignant pulmonary nodules. A combination of gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) was used to profile the plasma metabolites in 17 patients with malignant SPNs, 15 patients with benign SPNs and 20 healthy controls. The metabolic profiles were assayed using OPLS-DA, and further analyzed to identify marker metabolites related to diseases. Both GC/MS- and LC/MS-derived models showed clear discriminations in metabolic profiles among three groups. It was found that 63 metabolites (12 from GC/MS, 51 from LC/MS) contributed to the differences. Of these, 48 metabolites showed same change trend in both malignant and benign SPNs as compared with healthy controls, indicating some common pathways including inflammation and oxidative injury shared by two diseases. In contrast, 14 metabolites constituted distinct profiles that differentiated malignant from benign SPNs, which might be a unique biochemical feature associated with lung cancer. Overall, our data suggested that integration of two highly sensitive and complementary metabolomics platforms could enable a comprehensive metabolic profiling and assist in discrimination malignant from benign SPNs.

MicroRNA as a new factor in lung and esophageal cancer

Lung cancer is the most lethal cancer due to late detection in advanced stages; early diagnosis of lung cancer allows surgical treatment and improves the outcome. The prevalence of gastroesophageal reflux-related adenocarcinomas of the esophagus is increasing; repetitive surveillance endoscopies are necessary to detect development of cancer. A blood-based biomarker would simplify the diagnosis and treatment of both diseases. MicroRNAs (miRNAs) are short RNA strands that interfere with protein production. miRNAs play pivotal roles in cell homeostasis, and dysregulation of miRNAs can lead to the development of cancer. miRNAs can be found in all body fluids and have been proposed to serve as messengers between closely localized cells but also distant organs. Cancer cells actively secrete miRNAs, and these miRNA profiles can be found in blood. We outline, here, how these miRNAs may aid in diagnosis and treatment of lung and esophageal cancers, as well as their apparent limitations.

Large noncoding RNA HOTAIR enhances aggressive biological behavior and is associated with short disease-free survival in human non-small cell lung cancer

HOTAIR is one of long non-coding RNAs and its expression correlates with the prognosis and metastasis in various cancers. We showed that HOTAIR expression has an important role in the development of non-small cell lung cancer (NSCLC). In this study, we examined the expression of HOTAIR in 77 NSCLCs, their corresponding normal lung tissues and 6 brain metastases by quantitative real-time RT-PCR. High expression of HOTAIR (tumor/normal ratio ⩾2) was detected in 17 patients (22.1%) and was frequently found in patients with advanced stage, lymph node metastasis or lymph-vascular invasion and short disease free interval. Furthermore, brain metastases show significantly higher HOTAIR expression compared to primary cancer tissues. HOTAIR-expressing A549 cells showed induced cell migration and anchorage-independent cell growth in vitro. These results indicate the expression of HOTAIR enhanced the aggressive behavior of NSCLC cells.

Screening and early detection of lung cancer

The greatest news of the past year in this field was the first large-scale early detection trial that could prove a 20% reduction in lung cancer-related mortality by screening high-risk individuals with low-dose computed tomography (LDCT). Several expert groups and medical societies have assessed the data and concluded that LDCT screening for lung cancer is, however, not ready for large-scale population-based implementation. Too many open questions remain, such as definition of the at-risk population, timing and intervals of screening, optimal method of acquisition and interpretation of the images, how to handle (false) positive findings, and especially cost-effectiveness in relation to other lung cancer prevention strategies, mainly smoking cessation. Further analyses and several ongoing European trials are eagerly awaited. Much hope also resides in the use of biomarkers, as their use in, e.g., blood or exhaled air may provide more easy-to-use tests to better stratify high-risk populations for screening studies. While exciting research is ongoing in this domain--e.g. with microRNAs--none of the tests has yet reached sufficient validation for clinical use. Early central lung cancers are more difficult to visualise by CT. For these patients, standard bronchoscopy, complemented by autofluoresence endoscopy, has been studied in different screening and follow-up settings.

Circulating miRNAs as sensitive and specific biomarkers for the diagnosis and monitoring of human diseases: promises and challenges

The regulation and modulation of gene expression has been a central focus of modern biomedical research ever since the first molecular elucidation of DNA. The cellular mechanisms by which genes are expressed and repressed hold valuable insight for maintaining tissue homeostasis or conversely provide mechanistic understanding of disease progression. Hence, the discovery of the first miRNA in humans roughly a decade ago profoundly shook the previously established dogmas of gene regulation. Since, these small RNAs of around 20 nucleotides have unquestionably influenced almost every area of medical research. This momentum has now spread to the clinical arena. Hundreds of papers have already been published shedding light on the mechanisms of action of miRNAs, their profound stability in almost every bodily fluid and relating their presence to disease state and severity of disease progression. In this review, we explore the diagnostic potential of miRNAs in the clinical laboratory with a focus on studies reporting the detection of miRNAs in blood and urine for investigation of human disease. Sensitivities, specificities, areas under the curve, group descriptions and miRNAs of interest for 69 studies covering a broad range of diseases are provided. We discuss the practicality of miRNAs in the screening, diagnosis and prognosis of a range of pathologies. Characteristics and pitfalls of miRNA detection in blood are also discussed. The topics covered here are pertinent in the design of future miRNA-based detection strategies for use in clinical biochemistry laboratory settings.

Downregulation of miR-486-5p contributes to tumor progression and metastasis by targeting protumorigenic ARHGAP5 in lung cancer

We have previously shown that miR-486-5p is one of the most downregulated micro RNAs in lung cancer. The objective of the study was to investigate the role of miR-486-5p in the progression and metastasis of non-small-cell lung cancer (NSCLC). We evaluated miR-486-5p expression status on 76 frozen and 33 formalin-fixed paraffin-embedded tissues of NSCLC by quantitative reverse transcriptase PCR to determine its clinicopathologic significance. We then performed function analysis of miR-486-5p to determine its potential roles on cancer cell migration and invasion in vitro and metastasis in vivo. We also investigated the target genes of miR-486-5p in lung tumorigenesis. miR-486-5p expression level was significantly lower in lung tumors compared with their corresponding normal tissues (P<0.0001), and associated with stage (P=0.0001) and lymph node metastasis of NSCLC (P=0.0019). Forced expression of miR-486-5p inhibited NSCLC cell migration and invasion in vitro and metastasis in mice by inhibiting cell proliferation. Furthermore, ectopic expression of miR-486-5p in cancer cells reduced ARHGAP5 expression level, whereas miR-486-5p silencing increased its expression. Luciferase assay demonstrated that miR-486-5p could directly bind to the 3'-untranslated region of ARHGAP5. The expression level of miR-486-5p was inversely correlated with that of ARHGAP5 in lung tumor tissues (P=0.0156). Reduced expression of ARHGAP5 considerably inhibited lung cancer cell migration and invasion, resembling that of miR-486-5p overexpression. miR-486-5p may act as a tumor-suppressor contributing to the progression and metastasis of NSCLC by targeting ARHGAP5. miR-486-5p would provide potential diagnostic and therapeutic targets for the disease.

Personalized medicine in screening for malignant disease: a review of methods and applications

Personalized medicine (PM) is currently a hot topic in the professional world. It is often called the medicine of the future and has already achieved resounding success in the area of targeted therapy. Nevertheless, integration of the concepts of PM into routine clinical practice is slow. This review is intended to give an overview of current and potential applications of PM in oncology. PM could soon play a decisive role, especially in screening. The relevance of PM in screening was examined in the case of four common cancers (colorectal cancer, lung cancer, breast cancer, and prostate cancer). A literature search was performed. This showed that biomarkers in particular play a crucial role in screening. In summary, it can be emphasized that there are already numerous known promising biomarkers in malignant disease. This results in several possibilities for individualizing and revolutionizing screening.

Diagnostic value of circulating microRNAs for lung cancer: a meta-analysis

BACKGROUND

Lung cancer is a leading cause of cancer mortality, and it shows a high incidence worldwide. Circulating microRNAs have been proposed as diagnostic indicators of lung cancer, but inconsistent results in the literature have prevented their widespread use in diagnosis. The present meta-analysis aimed to systematically evaluate the diagnostic accuracy of circulating microRNAs for lung cancer.

METHODS

Several research databases were searched systematically for studies of the accuracy of circulating microRNAs as diagnostic indicators of lung cancer. Results from different studies were pooled using random-effects models. Summary receiver operating characteristic (SROC) curves were used to assess the overall performance of microRNA-based assays.

RESULTS

Thirteen publications were included in the meta-analysis. The following summary estimates were obtained for the performance of circulating microRNAs in lung cancer diagnosis: sensitivity, 0.85 (95% confidence intervals [CI]: 0.83-0.87); specificity, 0.84 (95% CI: 0.81-0.86); positive likelihood ratio, 5.23 (95% CI: 3.75-7.29); negative likelihood ratio, 0.20 (95% CI: 0.14-0.27); and diagnostic odds ratio, 31.77 (95% CI: 16.98-59.42). The SROC curve indicated a maximum joint sensitivity and specificity of 0.85, with an area under the curve of 0.92.

CONCLUSION

Circulating microRNAs show significant potential as diagnostic markers of lung cancer. The results of this meta-analysis justify larger, more rigorous studies to confirm such a diagnostic role.

MicroRNA and Epigenetics: Diagnostic and Therapeutic Opportunities

MicroRNAs (miRNAs) are a large family of post-transcriptional regulators of gene expression that control cellular and developmental processes by targeting messenger RNAs (mRNA). These small non-coding RNAs (ncRNAs) are aberrantly expressed in cancer, and are known to contribute to tumorigenesis and disease progression. Therapeutic strategies based on modulating miRNAs activity are emerging due to the ability of these ncRNAs to influence cellular behavior. MiRNA levels predict disease prognosis and overall patient survival, and reconstituting their basal levels has been proven to inhibit tumor growth and metastasis. Different delivery mechanisms have been tested in vivo, however many challenges need to be overcome before their utilization in the clinic. Moreover, it has been found that circulating miRNAs in body fluids have the potential to reshape cancer diagnosis and prognosis by functioning as biomarkers and indicators of progression and metastasis. These miRNAs as biofluids-based biomarkers provide an alternative strategy for early diagnosis and treatment of cancer patients.

Altered serum microRNAs as biomarkers for the early diagnosis of pulmonary tuberculosis infection

Background

Pulmonary tuberculosis (TB) is a highly lethal infectious disease and early diagnosis of TB is critical for the control of disease progression. The objective of this study was to profile a panel of serum microRNAs (miRNAs) as potential biomarkers for the early diagnosis of pulmonary TB infection.

Methods

Using TaqMan Low-Density Array (TLDA) analysis followed by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) validation, expression levels of miRNAs in serum samples from 30 patients with active tuberculosis and 60 patients with Bordetella pertussis (BP), varicella-zoster virus (VZV) and enterovirus (EV) were analyzed.

Results

The Low-Density Array data showed that 97 miRNAs were differentially expressed in pulmonary TB patient sera compared with healthy controls (90 up-regulated and 7 down-regulated). Following qRT-PCR confirmation and receiver operational curve (ROC) analysis, three miRNAs (miR-361-5p, miR-889 and miR-576-3p) were shown to distinguish TB infected patients from healthy controls and other microbial infections with moderate sensitivity and specificity (area under curve (AUC) value range, 0.711-0.848). Multiple logistic regression analysis of a combination of these three miRNAs showed an enhanced ability to discriminate between these two groups with an AUC value of 0.863.

Conclusions

Our study suggests that altered levels of serum miRNAs have great potential to serve as non-invasive biomarkers for early detection of pulmonary TB infection.

Cell-free microRNAs as diagnostic, prognostic, and predictive biomarkers for lung cancer

Lung cancer is the most common cancer worldwide, accounting for over 1.37 million deaths annually. The clinical outcome and management of lung cancer patients could be substantially improved by the implementation of non-invasive biomarker assays for the early detection, prognosis as well as prediction and monitoring of treatment response. MicroRNAs (miRNAs) have been implicated in the regulation of virtually all signaling circuits within a cell and their dysregulation has been shown to play an essential role in the development and progression of cancer. Recently, miRNAs were found to be released into the circulation and to exist there in a remarkably stable form. Furthermore, various cancers were shown to leave specific miRNA fingerprints in the blood of patients suggesting that cell-free miRNAs could serve as non-invasive biomarkers for the detection or monitoring of cancer and putative therapeutic targets. Since that, a considerable effort has been devoted to decode the information carried by circulating miRNAs. In the current review, we give an insight into the mechanisms of miRNA release into the bloodstream, their putative functional significance and systematically review the studies focused on the identification of cell-free miRNAs with the diagnostic, prognostic, and predictive significance in lung cancer and discuss their potential clinical utility.

Clinical applications for microRNAs in cancer

The discovery that noncoding components of the genome, including microRNA (miRNA or miR), can contribute to the pathogenesis of cancer has led investigators to contemplate using these molecules to guide clinical decision making. Currently, miRNA signatures are being applied in human clinical trials and miRNA-directed therapy is under way, with miR-122 targeting in hepatitis C (HCV) being the most developed therapy thus far. miRNA-based targeting in cancer is not far behind, with several private companies developing therapeutics. We are recognizing the potential for miRNA biology to clarify both the molecular pathogenesis of cancer and the inherent complexities in translating its biology to clinics. An increased understanding of fundamental miRNA biology, improved bioinformatics, and directed in vivo targeting while minimizing off-target effects and toxicity will be required for successful translational application. Here, we provide an overview of miRNAs, with a focus on aspects of translating bench-based discoveries to the clinic.

MicroRNAs as potential biomarkers in human solid tumors

MicroRNAs (miRNAs) regulate the expression of approximately 30% of protein-coding genes. Functions of miRNAs are essential to maintain a steady state of cellular machinery. Dysregulations of miRNAs play pivotal roles in the initiation and progression of malignancies. Abnormal miRNA expressions have been found in a variety of human solid tumors. Furthermore, extracellular miRNAs could circulate in body fluids, and hence show great promise for refining diagnosis and prognosis of cancer. Here we review the progress of analysis of microRNAs as a potential approach for diagnosis and prognosis of solid cancer. We will also discuss obstacles in developing miRNAs as circulating biomarkers.

Role of microRNAs in lung cancer: microRNA signatures in cancer prognosis

Lung cancer-related mortality is the most common cause of cancer death worldwide. Detecting lung cancer at an earlier stage and, ideally, predicting who will develop the disease and particularly the most aggressive forms of cancer are the biggest challenge. MicroRNAs (miRNAs) are short, noncoding RNA molecules with regulatory function on protein-coding genes. Because of their fundamental role in development and differentiation, their involvement in the biological mechanisms underlying tumorigenesis, as well as their low complexity, stability, and easy detection, they represent a promising class of tissue- and blood-based biomarkers of cancer. We summarize the current literature on the use of microRNAs as diagnostic and prognostic tools in lung cancer and discuss the relevant clinical implications of these findings.

Circulating microRNAs: new biomarkers in diagnosis, prognosis and treatment of cancer (review)

MicroRNAs (miRNAs) are small non-coding, endogenous, single-stranded RNAs. MiRNAs have been implicated in different areas such as the immune response, neural development, DNA repair, apoptosis, oxidative stress response and cancer. However, while the majority of miRNAs are found intracellularly, a significant number of miRNAs have been observed outside of cells, including various body fluids. Circulating miRNAs function as 'extracellular communication RNAs' that play an important role in cell proliferation and differentiation. MiRNA regulation is essential to many cellular processes, and escape from this regulatory network seems to be a common characteristic of several disease processes and malignant transformation. The interest in circulating miRNAs reflects in fact their central role in regulation of gene expression and the implication of miRNA-specific aberrant expression in the pathogenesis of cancer, cardiac, metabolic, neurologic, immune-related diseases as well as others. In our review we aimed to summarize the data related to the action of cellular miRNAs on the onset of various diseases, thus bringing together some of the latest information available on the role of circulating miRNAs. Additionally, the role of circulating miRNAs could be particularly relevant in the context of neoplastic diseases. At least 79 miRNAs have been reported as plasma or serum miRNA biomarkers of solid and hematologic tumors. Circulating miRNA profiling could improve the diagnosis of cancer, and could predict outcome for cancer patients, while the profiling of alterations in circulating miRNA that may signal a predisposition to cancer, could also be a therapeutic target in these patients.

Circulating microRNAs in cancer: diagnostic and prognostic significance

The involvement of microRNAs (miRs) in numerous pathological conditions is well established. In many kinds of cancer cells and animal models, various miRs have been shown to act as oncogenes or tumor suppressors. Recently, it was found that circulating miRs can be detected, and may be associated, with the clinicopathological features and prognosis of cancers, thus, providing potential novel diagnostic and prognostic markers for malignancies in humans. This review aims to address these issues based on recently published literature.

[Extracellular miRNA: a novel molecular biomarker for lung cancer]

Though continuous development and progress have been made in the early diagnosis and treatment of cancer, it is still difficult to find a sensitive, accurate and minimally invasive biomarker for cancer diagnosis and treatment. MicroRNA (miRNA) is a class of non-coding small endogenous RNAs of 21-24 nucleotides in length. As a novel molecular biomarker, extracellular miRNA (ec-miRNA) has the potential to be a minimally invasive, highly sensitive and highly specific marker in cancer diagnosis. Many research achievements of ec-miRNA have been accumulated in recent years. In this paper, the origin, function and detection of ec-miRNA, its role in lung cancer diagnosis as a novel molecular biomarker, and some issues are reviewed.

Diagnostic and prognostic significance of serum microRNAs in colorectal cancer

MicroRNAs are short non-coding RNA molecules involved in the regulation of gene expression. There are few studies related to the determination of serum microRNAs in colorectal cancer. The identification of microRNAs in peripheral blood as noninvasive markers of tumor disease may lead to potential applications, although further clinical studies focusing on serum microRNAs are required to determine their clinical significance for the diagnosis and prognosis outcome of colorectal cancer.

miR-210: the master hypoxamir

MicroRNAs are small non-coding RNAs implicated mainly in post-transcriptional gene silencing by interacting with the untranslated region of the transcript. miR-210 represents major hypoxia-inducible miRs, also known as hypoxamirs, which is ubiquitously expressed in a wide range of cells, serving versatile functions. This review article summarizes the current progress on biogenesis of miR-210 and its physiological roles including arrest of cell proliferation, repression of mitochondrial respiration, arrest of DNA repair, vascular biology, and angiogenesis. Given the fact that miR-210 is aberrantly expressed in a number of diseases such as tumor progression, myocardial infarction and cutaneous ischemic wounds, miR-210 could serve as an excellent candidate for prognostic purposes and therapeutic intervention. With the advancement of computational prediction, high-throughput target validation methodology, sequencing, proteomic analysis, and microarray, it is anticipated that more down-stream targets of miR-210 and its associated biological consequences under hypoxia will be unveiled establishing miR-210 as a major hub in the biology of hypoxia-response.

Circulating miRNA is a novel marker for head and neck squamous cell carcinoma

The aim of the study is to investigate the alteration of plasma miRNA in head and neck squamous cell carcinoma (HNSCC). Altered microRNAs (miRNAs) expression has been found in many cancers, including lung cancer, breast cancer, prostate cancer, bladder cancer and colorectal cancer. Many recent studies have demonstrated that aberrant plasma miRNAs were also found in various types of cancers. However the alteration of plasma expression in HNSCC remains unclear. In this present study, the expression profiles of ten miRNAs, let-7a, miR-21, miR26b, miR-34c, miR-99a, miR-133a, miR-137, miR-184, miR-194a, and miR-375, in plasma from 50 patients and 36 healthy subjects were evaluated using real-time quantitative polymerase chain reaction (PCR). Our results demonstrated that the expression level of miR-21 was significantly up-regulated in plasma samples obtained from HNSCC patients (p < 0.01) than those from healthy subjects, which were in consistent with our finding in HNSCC tissues. A 7.7-fold increase of miR-21 in cancerous parts when compared to their non-cancerous counterparts (p < 0.0001) was observed in HNSCC tissues. In addition, the expression levels of miR-21 and miR-26b were both reduced in post-operative HNSCC patients with good prognosis. In contrast, the concentration of plasma miR-21 and miR-26b stayed high after tumor removal in the expired cases. Our study suggests that detecting circulating miR-21 and miR-26b pre- and post-operatively might provide a novel tumor marker for HNSCC.

Mechanistic Roles of Noncoding RNAs in Lung Cancer Biology and Their Clinical Implications

Lung cancer biology has traditionally focused on genomic and epigenomic deregulation of protein-coding genes to identify oncogenes and tumor suppressors diagnostic and therapeutic targets. Another important layer of cancer biology has emerged in the form of noncoding RNAs (ncRNAs), which are major regulators of key cellular processes such as proliferation, RNA splicing, gene regulation, and apoptosis. In the past decade, microRNAs (miRNAs) have moved to the forefront of ncRNA cancer research, while the role of long noncoding RNAs (lncRNAs) is emerging. Here we review the mechanisms by which miRNAs and lncRNAs are deregulated in lung cancer, the technologies that can be applied to detect such alterations, and the clinical potential of these RNA species. An improved comprehension of lung cancer biology will come through the understanding of the interplay between deregulation of non-coding RNAs, the protein-coding genes they regulate, and how these interactions influence cellular networks and signalling pathways.

Update on biomarkers for the detection of lung cancer

Patients at risk for lung cancer may have subclinical disease for years before presentation. The diagnosis of this disease is primarily based on symptoms, and detection often occurs after curative intervention is no longer possible. At present, no lung cancer early-detection biomarker is clinically available. This study reviews the most recent advances in early detection and molecular diagnostic biomarkers for the detection of lung cancer. This review includes an overview of the various biological specimens and matrices in which these biomarkers could be analyzed, as well as the diverse strategies and approaches for identifying new biomarkers that are currently being explored. Several novel and attractive biomarker candidates for the early detection of lung cancer exist. A remarkable shift is taking place from research based on single markers to analyzing signatures that are more complex in order to take advantage of new high-throughput technologies. However, it is still necessary to validate the most promising markers and the standardization of procedures that will lead to specific clinical applications.

Meta-analysis of human lung cancer microRNA expression profiling studies comparing cancer tissues with normal tissues

BACKGROUND

Lung cancer is the major cause of cancer death globally, it is often diagnosed at an advanced stage and has one of the lowest survival rates of any type of cancer. The common interest in the field of lung cancer research is the identification of biomarkers for early diagnosis and accurate prognosis. There is increasing evidence to suggest that microRNAs play important and complex roles in lung cancer.

METHODS

A meta-analysis was conducted to review the published microRNA expression profiling studies that compared the microRNAs expression profiles in lung cancer tissues with those in normal lung tissues. A vote-counting strategy that considers the total number of studies reporting its differential expression, the total number of tissue samples used in the studies and the average fold change was employed.

RESULTS

A total of 184 differentially expressed microRNAs were reported in the fourteen microRNA expression profiling studies that compared lung cancer tissues with normal tissues, with 61 microRNAs were reported in at least two studies. In the panel of consistently reported up-regulated microRNAs, miR-210 was reported in nine studies and miR-21 was reported in seven studies. In the consistently reported down-regulated microRNAs, miR-126 was reported in ten studies and miR-30a was reported in eight studies. Four up-regulated microRNAs (miR-210, miR-21, miR-31 and miR-182) and two down-regulated mcroiRNAs (miR-126 and miR-145) were consistently reported both in squamous carcinoma and adenocarcinoma-based subgroup analysis, with the other 14 microRNAs solely reported in one or the other subset.

CONCLUSIONS

In conclusion, the top two most consistently reported up-regulated microRNAs were miR-210 and miR-21. The results of this meta-analysis of human lung cancer microRNA expression profiling studies might provide some clues of the potential biomarkers in lung cancer. Further mechanistic and external validation studies are needed for their clinical significance and role in the development of lung cancer.

MicroRNA expression changes after lung cancer resection: a follow-up study

MiRNAs are powerful biomarkers for detecting various diseases from tissue and body fluids. The potential of these molecules to monitor patients over time has, however, been less explored. We followed the fate of the plasma miRNome of lung cancer patients starting prior to surgery and ending 18 mo after surgery, with blood taken at three-month intervals. Principal component and clustering analysis showed that the differences of the overall miRNA patterns between the different time points were significantly smaller than between patients. For each patient we found a rather specific fluctuating miRNA pattern. We identified miRNAs that showed a significant correlation between expression level and time distance from surgery. A network analysis revealed 12 correlated miRNAs regulating 48 genes that were deregulated in lung cancer tissue. Our data underline the importance of studies that follow the fate of miRNAs over time, both to further our understanding of the biology of miRNA signatures and to establish these signatures as biomarkers.

Fluorescence In Situ Hybridization for MicroRNA Detection in Archived Oral Cancer Tissues

The noncoding RNA designated as microRNA (miRNA) is a large group of small single-stranded regulatory RNA and has generated wide-spread interest in human disease studies. To facilitate delineating the role of microRNAs in cancer pathology, we sought to explore the feasibility of detecting microRNA expression in formalin-fixed paraffin-embedded (FFPE) tissues. Using FFPE materials, we have compared fluorescent in situ hybridization (FISH) procedures to detect miR-146a with (a) different synthetic probes: regular custom DNA oligonucleotides versus locked nucleic acid (LNA) incorporated DNA oligonucleotides; (b) different reporters for the probes: biotin versus digoxigenin (DIG); (c) different visualization: traditional versus tyramide signal amplification (TSA) system; (d) different blocking reagents for endogenous peroxidase. Finally, we performed miR-146a FISH on a commercially available oral cancer tissue microarray, which contains 40 cases of oral squamous cell carcinoma (OSCC) and 10 cases of normal epithelia from the human oral cavity. A sample FISH protocol for detecting miR-146a is provided. In summary, we have established reliable in situ hybridization procedures for detecting the expression of microRNA in FFPE oral cancer tissues. This method is an important tool for studies on the involvement of microRNA in oral cancer pathology and may have potential prognostic or diagnostic value.

Increased miR-708 expression in NSCLC and its association with poor survival in lung adenocarcinoma from never smokers

PURPOSE

miRNA plays an important role in human disease and cancer. We seek to investigate the expression status, clinical relevance, and functional role of miRNA in non-small cell lung cancer.

EXPERIMENTAL DESIGN

We conducted miRNA expression profiling in matched lung adenocarcinoma and uninvolved lung using 56 pairs of fresh-frozen (FF) and 47 pairs of formalin-fixed, paraffin-embedded (FFPE) samples from never smokers. The most differentially expressed miRNA genes were evaluated by Cox analysis and log-rank test. Among the best candidate, miR-708 was further examined for differential expression in two independent cohorts. Functional significance of miR-708 expression in lung cancer was examined by identifying its candidate mRNA target and through manipulating its expression levels in cultured cells.

RESULTS

Among the 20 miRNAs most differentially expressed between tested tumor and normal samples, high expression level of miR-708 in the tumors was most strongly associated with an increased risk of death after adjustments for all clinically significant factors including age, sex, and tumor stage (FF cohort: HR, 1.90; 95% CI, 1.08-3.35; P = 0.025 and FFPE cohort: HR, 1.93; 95% CI, 1.02-3.63; P = 0.042). The transcript for TMEM88 gene has a miR-708 binding site in its 3' UTR and was significantly reduced in tumors high of miR-708. Forced miR-708 expression reduced TMEM88 transcript levels and increased the rate of cell proliferation, invasion, and migration in culture.

CONCLUSIONS

miRNA-708 acts as an oncogene contributing to tumor growth and disease progression by directly downregulating TMEM88, a negative regulator of the Wnt signaling pathway in lung cancer.

MicroRNAs As Biomarkers For Clinical Features Of Lung Cancer

Each year about 1.4 million people die from lung cancer worldwide. Despite efforts in prevention, diagnosis and treatment, survival rate remains poor for this disease. This unfortunate situation is largely due to the fact that a high proportion of cases are diagnosed at advanced stages, highlighting the great need for identifying new biomarkers in order to improve early diagnosis and treatment. Recent studies on microRNAs have not only shed light on their involvement in tumor development and progression, but also suggested their potential utility as biomarkers for subtype diagnostics, staging and prediction of treatment response. This review article summarizes the impact of microRNAs on lung cancer biology, and highlights their role in the detection and classification of lung cancer as well as direct targets for drug development.

Applications of MicroRNAs in the Diagnosis and Prognosis of Lung Cancer

INTRODUCTION: Lung cancer is the leading cause of cancer death worldwide, due to its late diagnosis and poor outcome. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the posttranscriptional levels by either degrading or blocking translation of messenger RNA targets. Accumulating evidence indicates that miRNAs play a pivotal role in the development and progression of human malignancies, including lung cancer. AREAS COVERED: In this review, the authors focus on 1) application of miRNA-based biomarkers to help classify lung cancer, 2) application of the miRNA biomarkers for the early detection of lung cancer, and 3) use of miRNAs as biomarkers to predict outcomes of lung cancer. EXPERT OPINION: MiRNAs provide promising biomarkers for the diagnosis and prognosis of lung cancer. The developed miRNA biomarkers should be comprehensively and prospectively validated in clinical trials before being used in laboratory settings.

Non-coding RNAs in cancer initiation and progression and as novel biomarkers

Cancer represents a complex group of heterogeneous diseases. While many cancers share fundamental biological processes (hallmarks of cancer) necessary for their development and progression, cancers also distinguish themselves by their dependence on distinct oncogenic pathways. Over the last decade, targeted therapies have been introduced to the clinic with variable success. In truth, single targeted therapies may be successful in only a subset of malignancies but insufficient to address malignancies that often rely on multiple pathways, thus evading single targeted agents. Investigators have recently identified potentially functional components of the human genome that were previously thought to have no biological function. This discovery has added to the already established complexity of gene regulation in the pathogenesis of cancer. Non-coding RNAs represent key regulators of gene expression. Improved knowledge of their biogenesis and function may in turn lead to a better understanding of the heterogeneity of malignancies and eventually be leveraged as diagnostic, prognostic and therapeutic targets. MicroRNAs (miRNAs or miRs) for example, have the capacity for the regulation of multiple genes and thus redirection or reprogramming of biological pathways. However, several other members of the non-coding RNA family may be of equal biological relevance. In this review, we provide a perspective on emerging concepts in the clinical application of miRNA and other non-coding RNAs as biomarkers in cancer with an eye on the eventual integration of both miRNA and other non-coding RNA biology into our understanding of cancer pathogenesis and treatment.