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

Are circulating microRNAs peripheral biomarkers for Alzheimer's disease?

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by memory loss, multiple cognitive abnormalities and intellectual impairments. Currently, there are no drugs or agents that can delay and/or prevent the progression of disease in elderly individuals, and there are no peripheral biomarkers that can detect AD early in its pathogenesis. Research has focused on identifying biomarkers for AD so that treatment can be begun as soon as possible in order to restrict or prevent intellectual impairments, memory loss, and other cognitive abnormalities that are associated with the disease. One such potential biomarker is microRNAs that are found in circulatory biofluids, such as blood and blood components, serum and plasma. Blood and blood components are primary sources where miRNAs are released in either cell-free form and then bind to protein components, or are in an encapsulated form with microvesicle particles. Exosomal miRNAs are known to be stable in biofluids and can be detected by high throughput techniques, like microarray and RNA sequencing. In AD brain, enriched miRNAs encapsulated with exosomes crosses the blood brain barrier and secreted in the CSF and blood circulations. This review summarizes recent studies that have identified miRNAs in the blood, serum, plasma, exosomes, cerebral spinal fluids, and extracellular fluids as potential biomarkers of AD. Recent research has revealed only six miRNAs - miR-9, miR-125b, miR-146a, miR-181c, let-7g-5p, and miR-191-5p - that were reported by multiple investigators. Some studies analyzed the diagnostic potential of these six miRNAs through receiver operating curve analysis which indicates the significant area-under-curve values in different biofluid samples. miR-191-5p was found to have the maximum area-under-curve value (0.95) only in plasma and serum samples while smaller area-under-curve values were found for miR-125, miR-181c, miR-191-5p, miR-146a, and miR-9. This article shortlisted the promising miRNA candidates and discussed their diagnostic properties and cellular functions in order to search for potential biomarker for AD.

A comparison between quantitative PCR and droplet digital PCR technologies for circulating microRNA quantification in human lung cancer

Background

Selected microRNAs (miRNAs) that are abnormally expressed in the serum of patients with lung cancer have recently been proposed as biomarkers of this disease. The measurement of circulating miRNAs, however, requires a highly reliable quantification method. Quantitative real-time PCR (qPCR) is the most commonly used method, but it lacks reliable endogenous reference miRNAs for normalization of results in biofluids. When used in absolute quantification, it must rely on the use of external calibrators. Droplet digital PCR (ddPCR) is a recently introduced technology that overcomes the normalization issue and may facilitate miRNA measurement. Here we compared the performance of absolute qPCR and ddPCR techniques for quantifying selected miRNAs in the serum.

Results

In the first experiment, three miRNAs, proposed in the literature as lung cancer biomarkers (miR-21, miR-126 and let-7a), were analyzed in a set of 15 human serum samples. Four independent qPCR and four independent ddPCR amplifications were done on the same samples and used to estimate the precision and correlation of miRNA measurements obtained with the two techniques. The precision of the two methods was evaluated by calculating the Coefficient of Variation (CV) of the four independent measurements obtained with each technique. The CV was similar or smaller in ddPCR than in qPCR for all miRNAs tested, and was significantly smaller for let-7a (p = 0.028). Linear regression analysis of the miRNA values obtained with qPCR and ddPCR showed strong correlation (p < 0.001).

To validate the correlation obtained with the two techniques in the first experiment, in a second experiment the same miRNAs were measured in a larger cohort (70 human serum samples) by both qPCR and ddPCR. The correlation of miRNA analyses with the two methods was significant for all three miRNAs. Moreover, in our experiments the ddPCR technique had higher throughput than qPCR, at a similar cost-per-sample.

Conclusions

Analyses of serum miRNAs performed with qPCR and ddPCR were largely concordant. Both qPCR and ddPCR can reliably be used to quantify circulating miRNAs, however, ddPCR revealed similar or greater precision and higher throughput of analysis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12896-016-0292-7) contains supplementary material, which is available to authorized users.

MicroRNA-210 and its theranostic potential

INTRODUCTION

MicroRNAs (miRNAs) are a set of small single-stranded noncoding RNAs with diverse biological functions. As a prototypical hypoxamir, human microRNA-210 (hsa-miR-210) is one of the most widely studied miRNAs thus far. In addition to its involvement in sophisticated regulation of numerous biological processes, miR-210 has also been shown to be associated with the development of different human diseases including various types of cancers, cardiovascular and cerebrovascular diseases, and immunological diseases. Given its multi-faceted functions, miR-210 may serve as a novel and promising theranostic target for prevention and treatment of diseases. Areas covered: This review aims to provide a comprehensive overview of miR-210, the regulation of its expression, biological functions and molecular mechanisms, with particular emphasis on its diagnostic and therapeutic potential. Expert opinion: Although the exact roles of miR-210 in various diseases have not been fully clarified, targeting miR-210 may be a promising therapeutic strategy. Further investigations are also needed to facilitate therapeutic-clinical applications of miR-210 in human diseases.

Diagnosing Lung Cancers through Examination of Micro-RNA Biomarkers in Blood, Plasma, Serum and Sputum: A Review and Summary of Current Literature

Lung cancer is the leading cause of cancer related morbidity and mortality worldwide. Currently, the vast majority of lung cancers are diagnosed at a late stage, when patients become symptomatic leading to dismal, less than 15% five-year survival rates. Evidence has demonstrated that screening computed tomography scans can be used to detect lung cancer, but these scans have high false positive rates. Therefore, there is a continued need for the development of minimally-invasive methods to screen the high risk population and diagnose lung cancer at an earlier, curable stage. One such promising area is the use micro-RNAs. These are short, non-coding RNA molecules that have been shown in previous research to be dysregulated in cancers. This review will focus on the potential use of miRNA levels in various biological fluids (whole blood, plasma, serum, and sputum) and demonstrate their potential utility as screening and diagnostic biomarkers for lung cancer. Current research will be analyzed and compared, and future directions in establishing the use of miRNAs for detecting lung cancer will be discussed.

Considering Exosomal miR-21 as a Biomarker for Cancer

Cancer is a fatal human disease. Early diagnosis of cancer is the most effective method to prevent cancer development and to achieve higher survival rates for patients. Many traditional diagnostic methods for cancer are still not sufficient for early, more convenient and accurate, and noninvasive diagnosis. Recently, the use of microRNAs (miRNAs), such as exosomal microRNA-21(miR-21), as potential biomarkers was widely reported. This initial systematic review analyzes the potential role of exosomal miR-21 as a general biomarker for cancers. A total of 10 studies involving 318 patients and 215 healthy controls have covered 10 types of cancers. The sensitivity and specificity of pooled studies were 75% (0.70–0.80) and 85% (0.81–0.91), with their 95% confidence intervals (CIs), while the area under the summary receiver operating characteristic curve (AUC) was 0.93. Additionally, we examined and evaluated almost all other issues about biomarkers, including cutoff points, internal controls and detection methods, from the literature. This initial meta-analysis indicates that exosomal miR-21 has a strong potential to be used as a universal biomarker to identify cancers, although as a general biomarker the case number for each cancer type is small. Based on the literature, a combination of miRNA panels and other cancer antigens, as well as a selection of appropriate internal controls, has the potential to serve as a more sensitive and accurate cancer diagnosis tool. Additional information on miR-21 would further support its use as a biomarker in cancer.

MicroRNA In Lung Cancer: Novel Biomarkers and Potential Tools for Treatment

Lung cancer is the leading cause of cancer death in men and women worldwide. The lack of specific and sensitive tools for early diagnosis as well as still-inadequate targeted therapies contribute to poor outcomes. MicroRNAs are small non-coding RNAs, which regulate gene expression post-transcriptionally by translational repression or degradation of target mRNAs. A growing body of evidence suggests various roles of microRNAs including development and progression of lung cancer. In lung cancer, several studies have showed that certain microRNA profiles classified lung cancer subtypes, and that specific microRNA expression signatures distinguished between better-prognosis and worse-prognosis lung cancers. Furthermore, microRNAs circulate in body fluids, and therefore may serve as promising biomarkers for early diagnosis of lung cancer as well as for predicting prognosis of patients. In the present review, we briefly summarize microRNAs in the development and progression of lung cancer, focusing on possible applications of microRNAs as novel biomarkers and tools for treatment.

An update on sputum MicroRNAs in lung cancer diagnosis

Lung cancer is one of the leading cause of cancer mortality in the world. It is well known that genetic damages could result in lung tumor genesis. Despite years of research, the survival rate of the patients has not been markedly improved. According to lack of high sensitivity and specificity in diagnostic tests, just about 15-20% of lung cancer cases are discovered prior to progression of the disease. In last decade, sputum biomarkers have been developed for early detection/diagnosis of lung cancer. MicroRNAs are a class of small endogenous noncoding RNAs, which act as post-transcriptional regulators. Some specific miRNAs can have multifunctions in lung development and their aberrant expression could induce lung tumor genesis. The differences in miRNAs between the normal and cancerous lung lead to emerging of a novel type of biomarkers, which can be helpful in screening of high risk individuals, diagnosis of lung cancer as well as its therapy.

Profiling cell-free and circulating miRNA: a clinical diagnostic tool for different cancers

Effective cancer management depends on early diagnosis and treatment. There are several microRNAs (miRNAs) which are used for detection of various cancers. Cell-free and circulating miRNAs originate from plasma, either from blood cells or endothelial cells. Cell-free and circulating miRNAs are very much important in the diagnosis and prognosis of cancer therapy. Admittedly, biological knowledge of extracellular miRNAs is still at its preliminary level. Recent discoveries of novel cell-free and circulating miRNAs from the body fluids are now being considered as important biomarkers that may help us in the early diagnosis of any cancer. In the present review, we highlight the biogenesis of miRNAs and their current extracellular pattern, the discovery of circulating miRNA, significant advantages, and different profiling techniques. Finally, we discuss the different circulating miRNAs such as miR-21, miR-20a, miR-155, miR‑221, miR-210, miR-218, miR-200-family, miR-141, miR-122, miR-486-5p, miR‑423-5p, miR-29a, and miR-500 for clinical diagnosis of various cancers. The present review may be beneficial for future researches concerned with miRNAs which are used for detection of various cancers.

Circulating Neutrophil MicroRNAs as Biomarkers for the Detection of Lung Cancer

Peripheral neutrophils are the predominant circulating leukocytes and an important component of innate and adaptive immune systems, which is a primary defense against cancer. MicroRNAs (miRNAs) can modulate neutrophil functions and play important roles in cancer pathogenesis by regulating neutrophil gene expression. To investigate if assessment of differential miRNA levels of peripheral neutrophils has the potential for diagnosis of non-small-cell lung cancer (NSCLC), we examine neutrophils of 15 patients with stage I NSCLC and 15 smokers without cancer. We identify five neutrophil miRNAs that have an abnormal level in patients with NSCLC versus smokers without cancer. In a training set of 82 patients with lung cancer and 73 controls, a set of two genes (miRs-26a-2-3p and 574-3p) are developed, producing 77.8% sensitivity and 78.1% specificity for NSCLC detection. Furthermore, in a testing set of 60 patients with lung cancer and 58 smokers, the performance of analyzing the two miRNAs for lung cancer detection is confirmed. This study for the first time shows that a neutrophil miRNA profile may serve as a new category of circulating biomarkers for the detection of NSCLC.

MicroRNA (miRNA) Profiling

MicroRNAs (miRNAs) are small, highly conserved noncoding RNA molecules involved in the regulation of gene expression. Since each miRNA regulates the expression of hundreds of target mRNAs, miRNAs could function as master coordinators, efficiently regulating fundamental cellular processes, including proliferation, apoptosis, and development. Furthermore, miRNAs may provide useful diagnostic and therapeutic targets in a variety of diseases. However, miRNA expression profiling is essential for the investigation of the biological functions and clinical applications of miRNAs. Therefore, in this chapter, we review and discuss commonly used techniques for miRNAs profiling, as well as their advantages and restrictions.

MicroRNAs in diffuse large B-cell lymphoma

The aberrant expression of microRNAs (miRs) has a significant impact on the biological characteristics of lymphocytes, and is important in the pathogenesis of diffuse large B-cell lymphoma (DLBCL). It has been demonstrated, using miR profiling and detecting distinct miR signatures, that certain miRs may accurately distinguish different subtypes and prognostic classifications of DLBCL, as well as distinguish DLBCL from other more indolent lymphomas, including follicular lymphoma. miRs are excellent biomarkers for cancer diagnosis and prognosis. In DLBCL, specific miR expression profiles in the tissues of patients are associated with prognosis and clinical outcome. Over the past decade, there has been substantial investigation concerning the pathogenetic, diagnostic and prognostic roles of miRs in DLBCL. The aim of the present review is to describe the aberrant expression of miRs in DLBCL, and the functions, potential clinical use and possible therapeutic targets of miRs in this disease.

Circulating Blood-Borne microRNAs as Biomarkers in Solid Tumors

One of the major challenges in cancer research is the identification of stable biomarkers that could be routinely measured in easily accessible samples. Human blood and other body fluids represent rich sources for the identification of novel biomarkers. It is apparent that the availability of these biomarkers would improve an early detection of asymptomatic disease and the clinical management of cancer. MicroRNAs have been described to be present in various types of body fluids including cell-free serum and plasma. These days, the involvement of microRNAs in molecular pathology of cancer is well established. Moreover, it seems that these molecules could be optimal noninvasive biomarkers owing to their high stability under storage and handling conditions and high sensitivity and specificity in various diseases. To date, more than 100 circulating microRNAs with the potential to serve as novel diagnostic, prognostic, or predictive biomarkers for different types of cancers have been identified, and this number is still increasing. However, there are major discrepancies in the findings by different research groups, and few commonly altered microRNAs have been reported in these studies. Further studies on large cohorts using uniform methodology are warranted to establish the clinical applicability of circulating microRNAs for solid tumors. Here, we summarize the tumor-specific profiles of blood-borne microRNAs and discuss their potential utility for personalized medicine of solid tumors.

Molecular profile of liquid biopsies: next generation biomarkers to improve lung cancer treatment

Molecular profiling of liquid biopsies is now emerging as pivotal for cancer biomarker discovery. The low-invasive nature of the approach used for collecting biospecimens (i.e. blood, urine, saliva, etc.) may allow a widespread application of novel molecular diagnostics based on liquid biopsies. This is relevant, for example, in cancer screening programmes where it is essential to reduce costs and the complexity of screening tests in order to increase study compliance and effectiveness. Here, I discuss recent advances in biomarkers for the early cancer detection and prediction of chemotherapy response based on the molecular profiling of liquid biopsies.

Circulating microRNA Biomarkers as Liquid Biopsy for Cancer Patients: Pros and Cons of Current Assays

An increasing number of studies have focused on circulating microRNAs (cmiRNA) in cancer patients’ blood for their potential as minimally-invasive biomarkers. Studies have reported the utility of assessing specific miRNAs in blood as diagnostic/prognostic biomarkers; however, the methodologies are not validated or standardized across laboratories. Unfortunately, there is often minimum limited overlap in techniques between results reported even in similar type studies on the same cancer. This hampers interpretation and reliability of cmiRNA as potential cancer biomarkers. Blood collection and processing, cmiRNA extractions, quality and quantity control of assays, defined patient population assessment, reproducibility, and reference standards all affect the cmiRNA assay results. To date, there is no reported definitive method to assess cmiRNAs. Therefore, appropriate and reliable methodologies are highly necessary in order for cmiRNAs to be used in regulated clinical diagnostic laboratories. In this review, we summarize the developments made over the past decade towards cmiRNA detection and discuss the pros and cons of the assays.

Differential miRNA expressions in peripheral blood mononuclear cells for diagnosis of lung cancer

Tremendous efforts have been made to develop cancer biomarkers by detecting circulating extracellular miRNAs directly released from tumors. Yet, none of the cell-free biomarkers has been accepted to be used for early detection of non-small cell lung cancer (NSCLC). Peripheral blood mononucleated cells (PBMCs) act as the first line of defense against malignancy in immune system, their dysfunction may occur as an early event in cancer immunogenicity or immune evasion. We proposed to investigate whether analysis of miRNA expressions of PBMCs has diagnostic value for NSCLC. We first used a microarray to analyze PBMCs of 16 stage I NSCLC patients and 16 cancer-free smokers, and identified seven PBMC miRNAs with a significantly altered expression level in NSCLC patients. In a training set of 84 NSCLC patients and 69 cancer-free smokers, a panel of two miRNAs (miRs-19b-3p and -29b-3p) were developed from the seven PBMC miRNAs, producing 72.62% sensitivity and 82.61% specificity in identifying NSCLC. Furthermore, the miRNAs could identify squamous cell lung carcinoma (SCC), a major type of NSCLC, with 80.00% sensitivity and 89.86% specificity. The expression levels of the miRNAs were independent of disease stage. In a testing set of 56 NSCLC patients and 46 controls, the performance of the biomarkers was reproducibly confirmed. The study presents the first in-depth analysis of PBMC miRNA profile of NSCLC patients. The assessment of PBMC miRNAs may provide a new diagnostic approach for the early detection of NSCLC.

Potential Role of MicroRNA-210 as Biomarker in Human Cancers Detection: A Meta-Analysis

We conducted this meta-analysis aimed to evaluate diagnostic accuracy of miR-210 in human cancers. A total of 673 cancer patients and 606 cancer-free individuals from 13 studies were contained in this meta-analysis. The overall diagnostic results in our study showed that the pooled sensitivity was 0.70, specificity was 0.76, and the AUC was 0.80. In addition, the PLR and NLR were 2.9 and 0.39, with DOR of 8. After the outliner exclusion detected by sensitivity analysis, these parameters had minimal change, which confirmed the stability of our work. The results in our studies showed that the miR-210 assay yielded relatively moderate accuracy in cancer patients and cancer-free individual differentiation. More basic researches are needed to highlight its role as supplement in clinical treatment.

Current State of Circulating MicroRNAs as Cancer Biomarkers

BACKGROUND

Numerous studies have demonstrated the existence of stable regulatory RNAs, microRNAs (miRNAs), in the circulation and have shown that the spectrum of these extracellular miRNAs is affected by various pathologic conditions including cancers.

CONTENT

Circulating miRNAs have been the focus of numerous cancer biomarker discovery efforts over the past few years; however, a considerable number of these studies have yielded inconsistent and irreproducible findings. Here, we have summarized and compared the results of studies covering 8 different cancer types to address key questions, including the possibility of using circulating miRNA to detect cancers and what factors may affect miRNA signatures. Although identifying circulating miRNA signatures to detect specific types of early stage cancers can be challenging, study results suggest that it may be possible to use miRNAs to detect cancers in general.

SUMMARY

Circulating miRNA is a rich source for potential disease biomarkers; however, factors, both intrinsic and extrinsic, that may affect measurement of circulating miRNA have not been fully characterized. Better understanding of intra- and intercellular miRNA trafficking and the fundamental biology of cancer cell–derived lipid vesicles may facilitate the development of circulating miRNA-based biomarkers for cancer detection and classification.

Expression profile analysis of microRNAs and downregulated miR-486-5p and miR-30a-5p in non-small cell lung cancer

Lung cancer is the leading cause of cancer-related mortality worldwide and although there have been improvements in treatment there is a low survival rate. The aim of the present study was to investigate the effect of microRNA (miRNA) on cell pathways. A miRNA microarray was used to profile miRNAs of lung cancer tissues. It was identified that 33 miRNAs with >2.0-fold change and FDR <0.05 were differentially expressed between the adjacent non-cancerous lung tissues and non-small cell lung cancers NSCLCs (P<0.005). The data were optimized in combination with physical interaction analysis to obtain crucial miRNAs. The results showed that differentially expressed miRNAs were associated with biological processes such as cell migration, protein phosphorylation and neuron differentiation, and signaling pathways such as MAPK, TGF-β and PI3K/Akt signaling pathways. Validation of significant miRNAs in independent 40 paired NSCLC tissues demonstrated that the expression level of miR-486-5p and miR-30a-5p was significantly downregulated in another 40 paired lung cancer tissues. Taken together, the results provided strong evidence of the possible involvement of miRNAs in the development and progression of NSCLC. Thus, the results are of importance for clinical investigators and for those who design miRNA‑based novel cancer therapeutics.

MicroRNA and MET in lung cancer

MicroRNAs (miRNAs) are a class of small non-protein coding RNAs that modulate important cellular functions via their post-transcriptional regulation of messenger RNAs (mRNAs). Recent evidences from multiple tumor types and model systems implicate miRNA dysregulation as a common mechanism of tumorigenesis, cancer progression and resistance to therapy. Several miRNAs are dysregulated in cancers and a single miRNA can have multiple targets involved in different oncogenic pathways. MET, the tyrosine kinase receptor for hepatocyte growth factor (HGF), has a central role in lung cancer development and in acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors; it has been predicted and shown to be the target gene of multiple miRNAs, which play a crucial role in controlling its activity in a stimulatory or inhibitory sense. In this review we will focus on the most important and recent studies about the role of miRNAs in the control of MET expression, reporting also the progress made using miRNAs for therapy of lung cancer.

Computational and in vitro Investigation of miRNA-Gene Regulations in Retinoblastoma Pathogenesis: miRNA Mimics Strategy

PURPOSE

Retinoblastoma (RB), a primary pediatric intraocular tumor, arises from primitive retinal layers. Several novel molecular strategies are being developed for the clinical management of RB. miRNAs are known to regulate cancer-relevant biological processes. Here, the role of selected miRNAs, namely, miR-532-5p and miR-486-3p, has been analyzed for potential therapeutic targeting in RB.

METHODS

A comprehensive bioinformatic analysis was performed to predict the posttranscriptional regulators (miRNAs) of the select panel of genes [Group 1: oncogenes (HMGA2, MYCN, SYK, FASN); Group 2: cancer stem cell markers (TACSTD, ABCG2, CD133, CD44, CD24) and Group 3: cell cycle regulatory proteins (p53, MDM2)] using Microcosm, DIANALAB, miRBase v 18, and REFSEQ database, and RNA hybrid. The expressions of five miRNAs, namely, miR-146b-5p, miR-532-5p, miR-142-5p, miR-328, and miR-486-3p, were analyzed by qRT–PCR on primary RB tumor samples (n = 30; including 17 invasive RB tumors and 13 noninvasive RB tumors). Detailed complementary alignment between 5’ seed sequence of differentially expressed miRNAs and the sequence of target genes was determined. Based on minimum energy level and piCTAR scores, the gene targets were selected. Functional roles of these miRNA clusters were studied by using mimics in cultured RB (Y79, Weri Rb-1) cells in vitro. The gene targets (SYK and FASN) of the studied miRNAs were confirmed by qRT-PCR and western blot analysis. Cell proliferation and apoptotic studies were performed.

RESULTS

Nearly 1948 miRNAs were identified in the in silico analysis, From this list, only 9 upregulated miRNAs (miR-146b-5p, miR-305, miR-663b, miR-299, miR-532-5p, miR-892b, miR-501, miR-142-5p, and miR-513b) and 10 downregulated miRNAs (miR-1254, miR-328, miR-133a, miR-1287, miR-1299, miR-375, miR-486-3p, miR-720, miR-98, and miR-122*) were found to be common with the RB serum miRNA profile. Downregulation of five miRNAs (miR-146b-5p, miR-532-5p, miR-142-5p, miR-328, and miR-486-3p) was confirmed experimentally. Predicted common oncogene targets (SYK and FASN) of miR-486-3p and miR-532-5p were evaluated for their mRNA and protein expression in these miRNA mimic-treated RB cells. Experimental overexpression of these miRNAs mediated apoptotic cell death without significantly altering the cell cycle in RB cells.

CONCLUSION

Key miRNAs in RB pathogenesis were identified by an in silico approach. Downregulation of miR-486-3p and miR-532-5p in primary retinoblastoma tissues implicates their role in tumorigenesis. Prognostic and therapeutic potential of these miRNA was established by the miRNA mimic strategy.

Recent advances of microRNA-based molecular diagnostics to reduce false-positive lung cancer imaging

Lung cancer is the leading cause of cancer deaths in the world. Advances in early detection crucial to enable timely curative surgery have been made in recent years. Cost-benefit profiles of lung cancer screening in smokers by low-dose computed tomography are still under evaluation. In particular, the high false-positive rates of low-dose computed tomography, together with the issue of overdiagnosis and the overall costs of screening, prompted a focus on the development of noninvasive complementary biomarkers to implement lung cancer screening. MicroRNA are a new class of blood-based biomarkers useful for early lung cancer detection and prognosis definition. Here, we discuss the seminal publications that reported circulating microRNA signatures with the greatest potential to impact clinical activity and patient care.

Molecular histology of lung cancer: from targets to treatments

Lung cancer is the leading cause of cancer-related death worldwide with a 5-year survival rate of less than 15%, despite significant advances in both diagnostic and therapeutic approaches. Combined genomic and transcriptomic sequencing studies have identified numerous genetic driver mutations that are responsible for the development of lung cancer. In addition, molecular profiling studies identify gene products and their mutations which predict tumour responses to targeted therapies such as protein tyrosine kinase inhibitors and also can offer explanation for drug resistance mechanisms. The profiling of circulating micro-RNAs has also provided an ability to discriminate patients in terms of prognosis/diagnosis and high-throughput DNA sequencing strategies are beginning to elucidate cell signalling pathway mutations associated with oncogenesis, including potential stem cell associated pathways, offering the promise that future therapies may target this sub-population, preventing disease relapse post treatment and improving patient survival. This review provides an assessment of molecular profiling within lung cancer concerning molecular mechanisms, treatment options and disease-progression. Current areas of development within lung cancer profiling are discussed (i.e. profiling of circulating tumour cells) and future challenges for lung cancer treatment addressed such as detection of micro-metastases and cancer stem cells.

Expression profile analysis of microRNAs in prostate cancer by next-generation sequencing

BACKGROUND

Prostate cancer (PCa) is the second leading cause of tumor mortality among males in western societies. In China, the diagnostic and fatality rate of PCa is increasing yearly.

METHODS

To characterize underlying molecular mechanisms, the microRNA (miRNA) profile of high-grade PCa, low-grade PCa, and benign prostate hyperplasia (BPH) were compared using high-throughput Illumina sequencing and quantitative real-time PCR (qRT-PCR) methods. Moreover, a variety of biological information softwares and databases were applied to predict the target genes of miRNA, molecular functions, and signal pathways.

RESULTS

Eighteen miRNAs were differentially expressed (fold change ≥ 2, P < 0.05), of which thirteen were upregulated and five were downregulated by sequencing. This was confirmed by qRT-PCR in more clinical tissue samples. In the tumors, miRNAs (miR-125b-5p, miR-126-5p, miR-151a-5p, miR-221-3p, and miR-222-3p) were significantly upregulated with downregulation of miR-486-5p. In addition, 13 novel miRNAs were identified from three prostate tissue libraries, with 12 of them assayed in 21 human normal tissues by qRT-PCR. Multiple databases indicated target genes for these differentially expressed miRNAs. Function annotation of target genes indicated that most of them tend to target genes involved in signal transduction and cell communication, especially cancer-related PI3K-Akt and p53 signaling pathway.

CONCLUSIONS

The small RNA transcriptomes obtained in this study uncovers six differentially expressed miRNAs and 12 novel miRNAs, and provides a better understanding of the expression and function of miRNAs in the development of PCa and reveals several miRNAs in PCa that may have biomarker and therapeutic potentials.

Expression and prognostic value of miR-486-5p in patients with gastric adenocarcinoma

MicroRNA (miR)-486-5p expression is often reduced in human cancers. However, its expression in gastric carcinoma and its relation to clinicopathological features and prognosis are unclear. Tissue microarrays were constructed from 84 patients with gastric adenocarcinoma (GC) who were undergoing radical resection. miR-486-5p expression was detected by miRNA-locked nucleic acid in situ hybridization, and its correlations with clinicopathological features and overall survival were analyzed. Bioinformatic studies predict that fibroblast growth factor 9 (FGF9) is a potential target gene of miR-486-5p. miR-486-5p was mainly located in the cytoplasm of GC cells and neighboring normal tissues. Compared with paracancerous normal tissue, miR-486-5p expression was decreased in 63.1% (53/84) of the GC samples, increased in 32.1% (27/84) and unchanged in 4.8% (4/84). FGF9 expression was decreased in 69.0% (58/84) of GC samples and increased in 31.0% (26/84) compared with normal paracancerous tissues using immunohistochemical analysis. Low or unchanged miR-486-5p expression (P = 0.002), tumor stage (P = 0.001), tumor status (P = 0.001), node status (P = 0.001), tumor size (P = 0.004), and depth of tumor invasion (P = 0.013) were significant negative prognostic predictors for overall survival in patients with GC. After stratification according to American Joint Committee on Cancer (AJCC) stage, low/unchanged miR-486-5p expression remained a significant predictor of poor survival in stage II (P = 0.024) and stage III (P = 0.003). Cox regression analysis identified the following predictors of poor prognosis: tumor status (hazard ratio [HR], 7.19; 95% confidence interval [CI], 1.75–29.6; P = 0.006), stage (HR, 2.62; 95%CI, 1.50–4.59; P = 0.001), lymph node metastasis (HR, 2.52; 95% CI, 1.27–4.99; P = 0.008), low/unchanged miR-486-5p (HR, 2.47; 95% CI, 1.35–4.52; P = 0.003), high level of FGF9 (HR, 2.41; 95% CI, 1.42–4.09; P = 0.001) and tumor size (HR, 2.50; 95% CI, 1.30–4.82; P = 0.006). Low or unchanged expression of miR-486-5p compared with neighboring normal tissues was associated with a poor prognosis, while high expression was associated with a good prognosis in GC. miR-486-5p may thus be useful for evaluating prognosis and may provide a novel target treatment in patients with GC.

MicroRNA as tools and therapeutics in lung cancer

Lung cancer is the number one cause of cancer related deaths. The lack of specific and accurate tools for early diagnosis and minimal targeted therapeutics both contribute to poor outcomes. The recent discovery of microRNAs (miRNAs) revealed a novel mechanism for post-transcriptional regulation in cancer and has created new opportunities for the development of diagnostics, prognostics and targeted therapeutics. In lung cancer, miRNA expression profiles distinguish histological subtypes, predict chemotherapeutic response and are associated with prognosis, metastasis and survival. Furthermore, miRNAs circulate in body fluids and hence may serve as important biomarkers for early diagnosis or stratify patients for personalized therapeutic strategies. Here, we provide an overview of the miRNAs implicated in lung cancer, with an emphasis on their clinical utility.

Significance of plasma hepatocyte growth factor in diagnosis of benign and malignant solitary pulmonary nodules

PURPOSE

We aimed to figure out the difference of serum hepatocyte growth factor (S-HGF) level between benign and malignant solitary pulmonary nodules (SPNs) patients.

METHODS

The study comprised 42 serum samples from SPNs patients and 10 serum samples of healthy donors. The HGF level was measured by the commercially enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

By statistical analysis, the S-HGF levels of the malignant SPNs patients were significantly higher than that of control group (P < 0.05). Moreover, the levels of S-HGF in malignant group were also significantly higher than that in benign group (P < 0.05), while there was no significant difference between the benign and control group (P > 0.05). The levels of S-HGF were also shown no statistically significant difference (P > 0.05) in different pathologic types of lung cancer patients. In addition, the incidence of malignant SPNs increased when the S-HGF level ≥ 250 pg/ml.

CONCLUSION

The detection of S-HGF level may be a new detection method used for the rapid diagnosis of benign and malignant SPNs.

MicroRNA-486-5p, which is downregulated in hepatocellular carcinoma, suppresses tumor growth by targeting PIK3R1

Deregulated microRNAs and their roles in carcinogenesis and cancer progression have attracted much attention. In previous studies conducted in our laboratory, the Illumina Solexa massively parallel signature sequencing of miRNomes in nontumor and hepatocellular carcinoma (HCC) tissues revealed that miR-486-5p was significantly downregulated in HCC, but its role in HCC development remains unknown. In this study, miR-486-5p levels in HCC tissues and matched control tissues, and in seven HCC cell lines (QGY-7701, QGY-7703, QGY-7404, SMMC-7721, Huh7, HepG2, and PCL/PRF/5) and human normal liver cells (HL-7702), were tested by real-time quantitative RT-PCR. We found that the level of miR-486-5p was significantly decreased in HCC tissue and in all seven HCC cell lines. Overexpression of miR-486-5p markedly suppressed HCC cell proliferation, migration and invasion in vitro, and inhibited HCC growth in vivo. Mechanistically, miR-486-5p was confirmed to directly target PIK3R1 expression, thereby suppressing phosphatidylinositol 3-kinase-AKT pathway activation, by dual luciferase reporter assay and real-time quantitative RT-PCR and western blot analysis. In addition, PIK3R1 knockdown mimicked the effects of miR-486-5p overexpression by inhibiting HCC growth, migration, and invasion. Furthermore, correlation analysis, Kaplan-Meier estimates and Cox proportional hazard models showed an inverse correlation between miR-486-5p and PIK3R1, as well as a shorter time to recurrence after HCC resection, in patients with lower miR-486-5p expression. Hence, we conclude that miR-486-5p, which is frequently downregulated in HCC, inhibits HCC progression by targeting PIK3R1 and phosphatidylinositol 3-kinase-AKT activation.

Cell-free microRNAs as cancer biomarkers: the odyssey of miRNAs through body fluids

Cell-free microRNAs (cfmiRNAs), also known as extracellular or secretory microRNAs, are an emerging class of miRNAs that are released or secreted by cells. These miRNAs are transferred through various body fluids. A growing body of research has recently revealed that cancer cells also secrete their distinctive cfmiRNAs to the extracellular environment highlighting the contribution of cfmiRNAs to cancer progression. CfmiRNAs show high stability in the body fluids. Three pathways have been proposed for their entry into the body fluids: passive release from broken, injured and dead cells; active secretion through microvesicles; and active secretion via microvesicle-free protein-dependent route. Active pathways seem to play leading roles in the delivery of miRNAs. Detection of cfmiRNAs is of particular relevance to their translation into the clinic. Much effort has been devoted to the development of highly sensitive and efficient approaches for detection purposes. Nevertheless, some barriers such as finding a unique internal control for all cancer types remain to be bypassed. This review aims to provide an insight into the promises represented by cfmiRNAs as cancer biomarkers and describes advances made in the identification of numerous types of extracellular miRNAs that have potential for use in the diagnosis of a variety of cancers.

Elevated serum annexin A1 as potential diagnostic marker for lung cancer: a retrospective case-control study

BACKGROUND

Annexin A1 was investigated as prognostic factor because of its apparent association with tumorigenesis. The aim of this study was to investigate the expression of annexin A1 in lung cancer patients, and analysed the relationship with respect to the clinico-pathological features and assessed whether annexin A1 as a potential serum marker for lung cancer.

METHODS

Expression of annexin A1 was examined using immunohistochemistry, in-situ hybridization, western blot and enzyme-linked immunosorbent assay. Sensitivities and specificities for annexin A1 serum test were determined using receiver operator characteristic curve and cutoff was defined based on 95% and 85% sensitivities.

RESULTS

Lung cancer tissues exhibited higher expression of annexin A1 than the normal tissues (P < 0.05) and the serum annexin A1 of lung cancer patients also exhibited higher level than control groups (P < 0.05). Moreover, increased serum annexin A1 was significantly associated with the pathological grade and clinical stage of lung cancer patients (P < 0.05). Using receiver operator characteristic curve analysis, the cutoffs for distinguishing lung cancer from normal and benign groups were 4.77 and 4.84 ng/ml respectively. The sensitivities of annexin A1 for distinguishing lung cancer from normal and benign groups were 98.9% and 97.4%, and specificities were 88.3% and 66.4%.

CONCLUSIONS

Up-regulation of serum annexin A1 was associated with pathological grade and clinical stage of lung cancer patients, which indicated that it could be considered molecular biomarker for diagnosis and prognosis of lung cancer.

Analysis of MicroRNAs in sputum to improve computed tomography for lung cancer diagnosis

INTRODUCTION

Computed tomography (CT) plays a central role in lung cancer diagnosis. However, CT has relatively low specificity, presenting a challenge in clinical settings. We previously identified 12 microRNAs (miRNAs) whose expressions in tumor tissues were associated with lung cancer.

METHODS

Using quantitative reverse transcriptase polymerase chain reaction, we aimed to identify miRNA biomarkers in sputum that could complement CT for diagnosis of lung cancer.

RESULTS

In a training set consisting of 66 lung cancer patients and 68 cancer-free smokers, 10 of the 12 miRNAs were differentially expressed between the cases and controls (p ≤ 0.01). From the miRNAs, a logistic regression model was built on the basis of miR-31 and miR-210, both of which had the best prediction for lung cancer, producing an area under receiver operating characteristic curve of 0.83. Combined use of the two miRNAs yielded 65.2% sensitivity and 89.7% specificity, CT had 93.9% sensitivity and 83.8% specificity for lung cancer diagnosis. Notably, combined analysis of the miRNA biomarkers and CT produced a higher specificity than does CT used alone (91.2% versus 83.8%; p < 0.05). The diagnostic performance of the biomarkers was confirmed in a testing set comprising 64 lung cancer patients and 73 cancer-free smokers.

CONCLUSION

The sputum miRNA biomarkers might be useful in improving CT for diagnosis of lung cancer, but further independent validation on an external and prospective cohort of patients is required.

Forensic miRNA: potential biomarker for body fluids?

In forensic investigation, body fluids represent an important support to professionals when detected, collected and correctly identified. Through many years, various approaches were used, namely serology-based methodologies however, their lack of sensitivity and specificity became difficult to set aside. In order to sidetrack the problem, miRNA profiling surged with a real potential to be used to identify evidences like urine, blood, menstrual blood, saliva, semen and vaginal secretions. MiRNAs are small RNA structures with 20-25 nt whose proprieties makes them less prone to degradation processes when compared to mRNA which is extremely important once, in a crime scene, biological evidences might be exposed to several unfavorable environmental factors. Recently, published studies were able to identify some specific miRNAs, however their results were not always reproducible by others which can possibly be the reflection of different workflow strategies for their profiling studies. Given the current blast of interest in miRNAs, it is important to acknowledge potential limitations of miRNA profiling, yet, the lack of such studies are evident. This review pretends to gather all the information to date and assessed a multitude of factors that have a potential aptitude to discrediting miRNA profiling, such as: methodological approaches, environmental factors, physiological conditions, gender, pathologies and samples storage. It can be asserted that much has yet to be made, but we pretend to highlight a potential answer for the ultimate question: Can miRNA profiling be used as the forensic biomarker for body fluids identification?

Clinical Aspect of MicroRNA in Lung Cancer

MicroRNAs (miRNAs) are a class of small noncoding RNAs that modulate target gene activity, and are aberrantly expressed in most types of cancer as well in lung cancer. A miRNA can potentially target a diverse set of mRNAs; further, it plays a critical role in lung tumorigenesis as well as affects patient outcome. Previous studies focused mainly on abnormal miRNAs expressions in lung cancer tissues. Interestingly, circulating miRNAs were identified in human plasma and serum in 2008. Since then, considerable effort has been directed to the study of circulating miRNAs as one of the biomarkers of lung cancer. miRNAs expression of tissues and blood in lung cancer patients is being analyzed by more researchers. Recently, to overcome the high false-positivity of low-dose chest computed tomography scan, miRNAs in lung cancer screening are being investigated. This article summarizes the recent researches regarding clinical applications of miRNAs in the diagnosis and management of lung cancer.

MicroRNA-486-5p targeting PIM-1 suppresses cell proliferation in breast cancer cells

MicroRNAs (miRNAs) are emerging as critical regulators in carcinogenesis and tumor progression. Recently, miR-486-5p has been proved to play an important role in several cancers, but its functions in the context of breast cancer (BC) remain unknown. In this study, we found that miR-486-5p expression is significantly downregulated in BC tissues and cell lines. Overexpression of miR-486-5p dramatically suppressed BC cell proliferation in vitro and in vivo, induced G0/G1 arrest, and promoted apoptosis. We subsequently identified the oncogene PIM-1 as a direct target of miR-486-5p in BC. Overexpression of PIM-1 attenuated the function of miR-486-5p in BC cells. Together, we conclude that miR-486-5p exerts its antiproliferative function by directly downregulating PIM-1 expression. This novel miR-486-5p/PIM-1 axis provides insight into the pathogenesis of BC and might be therapeutic targets for prevention or treatment of BC.

MicroRNA-21 identified as predictor of cancer outcome: a meta-analysis

BACKGROUND

Growing evidence from recent studies has revealed the association of microRNA-21 (mir-21) with outcomes in multiple cancers, but inconsistent findings have been reported, which rationalized a summary and analysis of available data to investigate the prognostic role of mir-21.

MATERIALS AND METHODS

Eligible studies were identified through several search strategies and assessed for quality. Data was extracted from studies in terms of baseline characteristics and key statistics such as hazard ratio (HR), 95% confidence interval (CI) and P value, which were utilized to calculate pooled effect size.

RESULTS

25 studies were included in the meta-analysis to evaluate the prognostic role of mir-21 in malignant tumors. Elevated mir-21 level was demonstrated to moderately predict poor overall survival (OS) (HR = 1.903, 95% CI: 1.713-2.113, P = 0.000) and disease-free survival (DFS) (HR = 1.574, 95% CI: 1.139-2.175, P = 0.006) by the fixed and random effect model respectively. Importantly, subgroup analysis disclosed significant association between increased mir-21 level in cancerous tissue and worse survival status. Furthermore, over-expression of mir-21 was an independent prognostic factor for non-small cell lung cancer (NSCLC) and pancreatic cancer patients, with the pooled HR being 2.153 (95% CI: 1.693-2.739, P = 0.000) and 1.976 (95% CI: 1.639-2.384, P = 0.000).

CONCLUSIONS

Over-expression of mir-21, especially in cancerous tissue, was effectively predictive of worse prognosis in various carcinomas. Non-invasive circulating mir-21, however, exhibited modest ability to discriminate outcomes. Major concerns about mir-21 assay standardization and selection of specimen need to be fully addressed before its practical implementation in management of cancer.

Design and Analysis for Studying microRNAs in Human Disease: A Primer on -Omic Technologies

microRNAs (miRNAs) are fundamental to cellular biology. Although only approximately 22 bases long, miRNAs regulate complex processes in health and disease, including human cancer. Because miRNAs are highly stable in circulation when compared with several other classes of nucleic acids, they have generated intense interest as clinical biomarkers in diverse epidemiologic studies. As with other molecular biomarker fields, however, miRNA research has become beleaguered by pitfalls related to terminology and classification; procedural, assay, and study cohort heterogeneity; and methodological inconsistencies. Together, these issues have led to both false-positive and potentially false-negative miRNA associations. In this review, we summarize the biological rationale for studying miRNAs in human disease with a specific focus on circulating miRNAs, which highlight some of the most challenging topics in the field to date. Examples from lung cancer are used to illustrate the potential utility and some of the pitfalls in contemporary miRNA research. Although the field is in its infancy, several important lessons have been learned relating to cohort development, sample preparation, and statistical analysis that should be considered for future studies. The goal of this primer is to equip epidemiologists and clinical researchers with sound principles of study design and analysis when using miRNAs.

Circulating miRNAs: a new generation of anti-doping biomarkers

MicroRNAs (miRNAs) are small non-coding RNAs that regulate a variety of biological processes. Cell-free miRNAs detected in blood plasma are used as specific and sensitive markers of physiological processes and some diseases. Circulating miRNAs are highly stable in body fluids, for example plasma. Therefore, profiles of circulating miRNAs have been investigated for potential use as novel, non-invasive anti-doping biomarkers. This review describes the biological mechanisms underlying the variation of circulating miRNAs, revealing that they have great potential as a new class of biomarker for detection of doping substances. The latest developments in extraction and profiling technology, and the technical design of experiments useful for anti-doping, are also discussed. Longitudinal measurements of circulating miRNAs in the context of the athlete biological passport are proposed as an efficient strategy for the use of these new markers. The review also emphasizes potential challenges for the translation of circulating miRNAs from research into practical anti-doping applications.

MicroRNAs in lung cancer

MicroRNAs have become recognized as key players in the development of cancer. They are a family of small non-coding RNAs that can negatively regulate the expression of cancer-related genes by sequence-selective targeting of mRNAs, leading to either mRNA degradation or translational repression. Lung cancer is the leading cause of cancer-related death worldwide with a substantially low survival rate. MicroRNAs have been confirmed to play roles in lung cancer development, epithelial-mesenchymal transition and response to therapy. They are also being studied for their future use as diagnostic and prognostic biomarkers and as potential therapeutic targets. In this review we focus on the role of dysregulated microRNA expression in lung tumorigenesis. We also discuss the role of microRNAs in therapeutic resistance and as biomarkers. We further look into the progress made and challenges remaining in using microRNAs for therapy in lung cancer.

Apolipoprotein A-I mimetic peptide 4F rescues pulmonary hypertension by inducing microRNA-193-3p

BACKGROUND

Pulmonary arterial hypertension is a chronic lung disease associated with severe pulmonary vascular changes. A pathogenic role of oxidized lipids such as hydroxyeicosatetraenoic and hydroxyoctadecadienoic acids is well established in vascular disease. Apolipoprotein A-I mimetic peptides, including 4F, have been reported to reduce levels of these oxidized lipids and improve vascular disease. However, the role of oxidized lipids in the progression of pulmonary arterial hypertension and the therapeutic action of 4F in pulmonary arterial hypertension are not well established.

METHODS AND RESULTS

We studied 2 different rodent models of pulmonary hypertension (PH): a monocrotaline rat model and a hypoxia mouse model. Plasma levels of hydroxyeicosatetraenoic and hydroxyoctadecadienoic acids were significantly elevated in PH. 4F treatment reduced these levels and rescued preexisting PH in both models. MicroRNA analysis revealed that microRNA-193-3p (miR193) was significantly downregulated in the lung tissue and serum from both patients with pulmonary arterial hypertension and rodents with PH. In vivo miR193 overexpression in the lungs rescued preexisting PH and resulted in downregulation of lipoxygenases and insulin-like growth factor-1 receptor. 4F restored PH-induced miR193 expression via transcription factor retinoid X receptor α.

CONCLUSIONS

These studies establish the importance of microRNAs as downstream effectors of an apolipoprotein A-I mimetic peptide in the rescue of PH and suggest that treatment with apolipoprotein A-I mimetic peptides or miR193 may have therapeutic value.

miRNAs as non-invasive biomarkers for lung cancer diagnosis

Lung cancer is a leading cause of cancer death and late diagnosis is one of the most important reasons for the high mortality rate. Circulating microRNAs (miRNAs) represent stable and reproducible markers for numerous solid tumors, including lung cancer, and have been hypothesized as non-invasive diagnostic markers. Serum, plasma or whole peripheral blood can be used as starting material, and several methodological approaches have been proposed to evaluate miRNA expression. The present review provides an in depth summary of current knowledge on circulating miRNAs in different types of biological samples used as diagnostic markers of lung cancer. We also evaluate the diagnostic accuracy of each miRNA or group of miRNAs in relation to the different housekeeping miRNAs used. Finally, the limitations and potential of miRNA analysis are discussed.

Multiple functions of hypoxia-regulated miR-210 in cancer

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression post-transcriptionally. miRNAs can be induced by a variety of stresses such as hypoxia, and are involved in diverse biological processes including differentiation, cell proliferation, cell death, and tumorigenesis. Hypoxia, a common feature of tumor microenvironment, can induce a number of miRNAs expression. miRNA-210 (miR-210) is one of the hypoxia-regulated-miRNAs, which has been investigated extensively in cancer. However, paradoxically opposing results were documented regarding whether it is an oncogene or a tumor suppressor, and whether it is a positive or negative prognostic biomarker. In the present review, we focus on the following investigations of miR-210: 1) its functions of as an oncogene, 2) its functions as a tumor suppressor, 3) its functions in mitochondrial metabolism, and finally, the diagnostic and prognostic value of miR-210 in cancer researches.

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.