Biomarkers and molecular testing for early detection, diagnosis, and therapeutic prediction of lung cancer

Identification of biomarkers for the early detection of non-small cell lung cancer: a systematic review and meta-analysis

Lung cancer (LC) causes few symptoms in the earliest stages, leading to one of the highest mortality rates among cancers. Low-dose computerised tomography (LDCT) is used to screen high-risk individuals, reducing the mortality rate by 20%. However, LDCT results in a high number of false positives and is associated with unnecessary follow-up and cost. Biomarkers with high sensitivities and specificities could assist in the early detection of LC, especially in patients with high-risk features. Carcinoembryonic antigen (CEA), cytokeratin 19 fragments and cancer antigen 125 have been found to be highly expressed during the later stages of LC but have low sensitivity in the earliest stages. We determined the best biomarkers for the early diagnosis of LC, using a systematic review of eight databases. We identified 98 articles that focussed on the identification and assessment of diagnostic biomarkers and achieved a pooled area under curve of 0.85 (95% CI 0.82-0.088), indicating that the diagnostic performance of these biomarkers when combined was excellent. Of the studies, 30 focussed on single/antigen panels, 22 on autoantibodies, 31 on miRNA and RNA panels, and 15 suggested the use of circulating DNA combined with CEA or neuron-specific enolase (NSE) for early LC detection. Verification of blood biomarkers with high sensitivities (Ciz1, exoGCC2, ITGA2B), high specificities (CYFR21-1, antiHE4, OPNV) or both (HSP90α, CEA) along with miR-15b and miR-27b/miR-21 from sputum may improve early LC detection. Further assessment is needed using appropriate sample sizes, control groups that include patients with non-malignant conditions, and standardised cut-off levels for each biomarker.

The Implication of Liquid Biopsy in the Non-small Cell Lung Cancer: Potential and Expectation

Nowadays, lung cancer has remained the most lethal cancer, despite great advances in diagnosis and treatment. However, a large proportion of patients were diagnosed with locally advanced or metastatic disease and have poor prognosis. Immunotherapy and targeted drugs have greatly improved the survival and prognosis of patients with advanced lung cancer. However, how to identify the optimal patients to accept those therapies and how to monitor therapeutic efficacy are still in dispute. In the past few decades, tissue biopsy, including percutaneous fine needle biopsy and surgical excision, has still been the gold standard for examining the gene mutation such as EGFR, ALK, ROS, and PD-1/PD/L1, which can indicate the follow-up treatment. Nevertheless, the biopsy techniques mentioned above were invasive and unrepeatable, which were not suitable for advanced patients. Liquid biopsy, accounting for heterogeneity compared with tissue biopsy, is an alternative technique for monitoring the mutation, and a large quantity of research has demonstrated its feasibility to detect the circulating tumor cell, cell-free DNA, circulating tumor DNA, and extracellular vesicles from peripheral venous blood. The proposal of the concept of precision medicine brings a novel medical model developed with the rapid progress of genome sequencing technology and the cross-application of bioinformation, which was based on personalized medicine. The emerging method of liquid biopsy might contribute to promoting the development of precision medicine. In this review, we intend to describe the liquid biopsy in non-small cell lung cancer in detail in the aspect of screening, diagnosis, monitoring, treatment, and drug resistance.

LCMD: Lung Cancer Metabolome Database

Lung cancer, one of the most common causes of cancer-related death worldwide, has been associated with high treatment cost and imposed great burdens. The 5-year postoperative survival rate of lung cancer (13%) is lower than many other leading cancers indicating the urgent needs to dissect its pathogenic mechanisms and discover specific biomarkers. Although several proteins have been proposed to be potential candidates for the diagnosis of lung cancer, they present low accuracy in clinical settings. Metabolomics has thus emerged as a very promising tool for biomarker discovery. To date, many lung cancer-related metabolites have been highlighted in the literature but no database is available for scientists to retrieve this information. Herein, we construct and introduce the first Lung Cancer Metabolome Database (LCMD), a freely available online database depositing 2013 lung cancer-related metabolites identified from 65 mass spectrometry-based lung cancer metabolomics studies. Researchers are able to explore LCMD via two ways. Firstly, by applying various filters in the “Browse Metabolites” mode, users can access a list of lung cancer-related metabolites that satisfy the filter specifications. For each metabolite, users can acquire the value of the fold change (cancer/normal), statistical significance (p-value) of the fold change, and the comparative research designs of all the mass spectrometry-based lung cancer metabolomics studies that identify this metabolite. Secondly, by applying various filters in the “Browse Studies” mode, users can obtain a list of mass spectrometry-based lung cancer metabolomics studies that satisfy the filter specifications. For each study, users can view the type of studied specimen, mass spectrometry (MS) method, MS data processing software, and differential analysis method, as well as all the identified lung cancer-related metabolites. Furthermore, the overview of each study is clearly illustrated by a graphical summary. The LCMD (http://cosbi7.ee.ncku.edu.tw/LCMD/) is the first database that brings together the meaningful information of lung cancer-related metabolites. The development of the LCMD is envisioned to promote the biomarker discovery of lung cancer.

Genetic Markers in Lung Cancer Diagnosis: A Review

Lung cancer is the most often diagnosed cancer in the world and the most frequent cause of cancer death. The prognosis for lung cancer is relatively poor and 75% of patients are diagnosed at its advanced stage. The currently used diagnostic tools are not sensitive enough and do not enable diagnosis at the early stage of the disease. Therefore, searching for new methods of early and accurate diagnosis of lung cancer is crucial for its effective treatment. Lung cancer is the result of multistage carcinogenesis with gradually increasing genetic and epigenetic changes. Screening for the characteristic genetic markers could enable the diagnosis of lung cancer at its early stage. The aim of this review was the summarization of both the preclinical and clinical approaches in the genetic diagnostics of lung cancer. The advancement of molecular strategies and analytic platforms makes it possible to analyze the genome changes leading to cancer development-i.e., the potential biomarkers of lung cancer. In the reviewed studies, the diagnostic values of microsatellite changes, DNA hypermethylation, and p53 and KRAS gene mutations, as well as microRNAs expression, have been analyzed as potential genetic markers. It seems that microRNAs and their expression profiles have the greatest diagnostic potential value in lung cancer diagnosis, but their quantification requires standardization.

Evaluation of chemiluminescent immunoassay quantitative detection for pro-gastrin-releasing peptide (ProGRP) in serum and plasma

OBJECTIVE

To evaluate a newly developed Hybiome ProGRP chemiluminescent assay.

METHODS

Analytical sensitivity, precision, recovery, and equivalency of serum and plasma, serum stability, and complement interference of the Hybiome ProGRP assay were evaluated. Serum specimens from 318 individuals including 38 small cell lung cancer (SCLC), 65 non-small cell lung cancer (NSCLC), 53 benign lung diseases, and 162 healthy controls were assessed using the Hybiome ProGRP assay and Roche Elecsys ProGRP assay, and the results were compared.

RESULTS

The Hybiome ProGRP assay showed good analytical sensitivity, precision, and accuracy, and it showed equivalence between serum and plasma and serum stability. The methodological comparison results showed good correlation between the Hybiome and Roche assays (slope, 0.9889; intercept, 1.28). Both the Hybiome and Roche assays showed good ability to distinguish between SCLC and NSCLC. Based on 95% specificity in the NSCLC cohort, a clinical differentiation cut-off for separating SCLC from NSCLC patients was 114 pg/mL for the Hybiome assay and 117 pg/mL for the Roche assay; the AUC was 0.9166 and the sensitivity was 71.05% for Hybiome and 0.9045 and 76.32% for Roche, respectively.

CONCLUSION

The Hybiome ProGRP chemiluminescent assay shows good analytical performance and good correlation with the Roche Elecsys ProGRP assay.

Integration of metabolomic and transcriptomic profiles to identify biomarkers in serum of lung cancer

We used blood serum samples collected from 31 lung cancer (LC) patients and 29 healthy volunteers in this study. Levels of serum metabolites were qualitative quantified with gas chromatography-mass spectrometry (GC-MS), and the data were analyzed by partial least-squares discrimination analysis (PLS-DA). Based on the Kyoto Encyclopedia of Genes and Genomes database, we performed pathway-based analysis utilizing metabolites presented at differential abundance between the LC serum samples and the normal healthy serum samples for systematical investigation on the metabolic alterations associated with LC pathogenesis. Finally, we analyzed the significantly enriched pathways as well as their relevant differentially expressed messenger RNAs, and drawn a correlation network plot to identify the serum metabolic biomarkers and the significantly altered metabolic pathways for LC. GC-MS analysis showed that 23 of the 169 metabolites identified were significantly different. PLS-DA model revealed that 13 of these metabolites were with variable importance > 1, and particularly five were with area under curve > 0.9. Pathway-based analysis demonstrated that five of eight enriched metabolic pathways were statistically significant with false discovery rate < 0.05. Lastly, the correlation networks between these pathways and their related genes suggested that 29 genes had correlation degree > 10, which were mainly engaged in the purine metabolism. In conclusion, we identified indole-3-lactate, erythritol, adenosine-5-phosphate, paracetamol and threitol as serum metabolic biomarkers for LC through metabolomics analysis. Besides, we identified the purine metabolism as the significantly altered metabolic pathway in LC with the help of transcriptomics analysis.

Reference intervals for serum progastrin-releasing peptide in healthy Chinese adults with electrochemiluminescence immunoassay

BACKGROUND

Reliable reference intervals for serum progastrin-releasing peptide (ProGRP) in healthy Chinese adults with electrochemiluminescence immunoassay (ECLIA) are still lacking in the Chinese population.

OBJECTIVES

The study aims to establish reference intervals for ProGRP with ECLIA in apparently healthy Chinese adults.

METHODS

A total of 384 apparently healthy individuals from six representative geographical regions in China were enrolled: 200 males and 184 females with a mean age of 43.4±12.2 years, and an age range from 21 to 85 years. Serum ProGRP levels were analyzed on Cobas e601 automatic immunoassay analyzer with ECLIA. Reference intervals for serum ProGRP with ECLIA were determined following CLSI C28-A3 guidelines using a nonparametric method.

RESULTS

In an apparently healthy Chinese population, the reference intervals for serum ProGRP with ECLIA were ⩽53.92 ng/L for adults aged 21-70 years and ⩽75.69 ng/L for adults aged >70 years, respectively.

CONCLUSIONS

The reference values for serum ProGRP with ECLIA in an apparently healthy Chinese population were established according to the CLSI C28-A3 document, providing a reference for the clinical work.

[Multicenter Evaluation of A New Progastrin-releasing Peptide (ProGRP) Immunoassay across Europe and China]

背景

在欧洲和中国进行Elecsys^®胃泌素释放肽前体（ProGRP）免疫检测的多中心评估研究。

方法

在欧洲的3个中心和中国的2个中心，在肺癌中，通过不精密度、稳定性、方法学比较和鉴别诊断能力来评价该检测法。

结果

5个分析物浓度的中间不精密度范围为变异系数：2.2%-6.0%。在不同储存条件下，血浆和血清样本均显示出良好的稳定性。在血浆中Elecsys^®和ARCHITECT检测（斜率1.02，截距-2.72 pg/mL）之间表现出良好的相关性。同时，Elecsys^®检测在血清和血浆样本之间表现出良好的相关性（斜率0.93，截距2.35 pg/mL；相关系数0.97）。ProGRP作为不受种族、年龄、性别或吸烟史相关影响的检测手段，可鉴别小细胞和非小细胞肺癌（NSCLC）；截断值为84 pg/mL时，曲线下面积为0.90，95%CI: 0.87-0.93；敏感性为78.3%，特异性为95%。ProGRP浓度中位数在良性病变（38 pg/mL）、其他恶性肿瘤（40 pg/mL）或NSCLC（39 pg/mL）中较低，而在3期以上慢性肾脏疾病中浓度较高（>100 pg/mL）。

结论

Elecsys^® ProGRP检测在血清和血浆中稳定性增加，较现有检测法明显更具优势。ProGRP检测在中国的首次评价在不同种族中显示出相当的鉴别能力。

Liquid biopsy for early detection of lung cancer

PURPOSE OF REVIEW

The possibility of complete recovery for a lung cancer patient depends on very early diagnosis, as it allows total surgical resection. Screening for this cancer in a high-risk population can be performed using a radiological approach, but this holds a certain number of limitations. Liquid biopsy could become an alternative and complementary screening approach to chest imaging for early diagnosis of lung cancer.

RECENT FINDINGS

Several circulating biomarkers indicative of lung cancer can be investigated in blood, such as circulating tumor cells, circulating free nucleic acids (RNA and DNA) and proteins. However, none of these biomarkers have yet been adopted in routine clinical practice and studies are ongoing to confirm or not the usefulness and practical interest in routine early diagnosis and screening for lung cancers.

SUMMARY

Several potential circulating biomarkers for the early detection of lung cancer exist. When coupled to thoracic imaging, these biomarkers must give diagnosis of a totally resectable lung cancer and potentially provide new recommendations for surveillance by imagery of high-risk populations without a detectable nodule. Optimization of the specificity and sensitivity of the detection methods as well as standardization of the techniques is essential before considering for daily practice a liquid biopsy as an early diagnostic tool, or possibly as a predictive test, of lung cancer.

High-Precision Profiling of Sialic Acid Expression in Cancer Cells and Tissues Using Background-Free Surface-Enhanced Raman Scattering Tags

Precise profiling of the sialic acid (SA) expression on the membrane of cancer cells is critical for early identification of cancers and assessment of cancer metastasis. However, the complex physiological environments often result in false positives with currently available imaging technologies. Herein, we have established a background-free surface-enhanced Raman scattering (SERS) imaging platform that allows high-precision profiling of SA expression in cancer cells and differentiation of clinically relevant cancer tissues with various metastasis degrees. Three-dimensional Raman imaging technique provided a deeper insight into visualizing the probe distribution and thus the SA expression at the single-cell level, without destructing the cells. This noninvasive, high-precision imaging technique could favor early diagnosis, staging, and monitoring therapeutic responses of cancers that are highly essential in clinical settings.

Recommendations from the European Society of Thoracic Surgeons (ESTS) regarding computed tomography screening for lung cancer in Europe

In order to provide recommendations regarding implementation of computed tomography (CT) screening in Europe the ESTS established a working group with eight experts in the field. On a background of the current situation regarding CT screening in Europe and the available evidence, ten recommendations have been prepared that cover the essential aspects to be taken into account when considering implementation of CT screening in Europe. These issues are: (i) Implementation of CT screening in Europe, (ii) Participation of thoracic surgeons in CT screening programs, (iii) Training and clinical profile for surgeons participating in screening programs, (iv) the use of minimally invasive thoracic surgery and other relevant surgical issues and (v) Associated elements of CT screening programs (i.e. smoking cessation programs, radiological interpretation, nodule evaluation algorithms and pathology reports). Thoracic Surgeons will play a key role in this process and therefore the ESTS is committed to providing guidance and facilitating this process for the benefit of patients and surgeons.

Progastrin-releasing peptide as a diagnostic and therapeutic biomarker of small cell lung cancer

BACKGROUND

Progastrin-releasing peptide (proGRP) is a recently identified biomarker of small cell lung cancer (SCLC). We evaluated the usefulness of plasma proGRP level as a tumor marker for diagnosis and treatment monitoring in patients with SCLC.

METHODS

Plasma samples were collected prospectively from 452 [212 non-small cell lung cancer (NSCLC), 105 SCLC, and 135 other diseases] patients who visited the hospital for tissue diagnosis. Plasma proGRP levels were measured using a two-step automated immunoassay.

RESULTS

The median proGRP level was significantly higher in patients with SCLC (892.7 pg/mL) than those with NSCLC (32.6 pg/mL, P<0.001) and other diseases (26.6 pg/mL, P<0.001). At cutoff level of 63 pg/mL, proGRP shows 85.7% sensitivity, 90.2% specificity, 72.5% positive predictive value and 95.4% negative predictive value in patients with SCLC. The area under the curve values were 0.93 for distinguishing SCLC from NSCLC, and 0.943 for distinguishing SCLC from the other conditions. Median proGRP level was higher in extensive disease (1,055.2 pg/mL) than limited disease (253.8 pg/mL, P=0.005). Median OS was significantly shorter in patients with extensive disease (6.0±0.7 months) than limited disease (12.7±4.5 months, P<0.01). Among the 39 patients with SCLC who were followed, the median proGRP levels of the 23 responders decreased after chemotherapy (P<0.001).

CONCLUSIONS

Plasma proGRP level could be a useful diagnostic and therapeutic monitoring biomarker for patients with SCLC and the initial level may help with SCLC tumor staging.

Long Noncoding RNAs as Novel Biomarkers Have a Promising Future in Cancer Diagnostics

Cancers have a high mortality rate due to lack of suitable specific early diagnosis tumor biomarkers. Emerging evidence is accumulating that lncRNAs (long noncoding RNAs) are involved in tumorigenesis, tumor cells proliferation, invasion, migration, apoptosis, and angiogenesis. Furthermore, extracellular lncRNAs can circulate in body fluids; they can be detected and strongly resist RNases. Many researchers have found that lncRNAs could be good candidates for tumor biomarkers and possessed high specificity, high sensitivity, and noninvasive characteristics. In this review, we summarize the detection methods and possible sources of circulating lncRNAs and outline the biological functions and expression level of the most significant lncRNAs in tissues, cell lines, and body fluids (whole blood, plasma, urine, gastric juice, and saliva) of different kinds of tumors. We evaluate the diagnostic performance of lncRNAs as tumor biomarkers. However, the biological functions and the mechanisms of circulating lncRNAs secretion have not been fully understood. The uniform normalization protocol of sample collection, lncRNAs extraction, endogenous control selection, quality assessment, and quantitative data analysis has not been established. Therefore, we put forward some recommendations that might be investigated in the future if we want to adopt lncRNAs in clinical practice.

Differential N-Glycosylation Patterns in Lung Adenocarcinoma Tissue

To decrease the mortality of lung cancer, better screening and diagnostic tools as well as treatment options are needed. Protein glycosylation is one of the major post-translational modifications that is altered in cancer, but it is not exactly clear which glycan structures are affected. A better understanding of the glycan structures that are differentially regulated in lung tumor tissue is highly desirable and will allow us to gain greater insight into the underlying biological mechanisms of aberrant glycosylation in lung cancer. Here, we assess differential glycosylation patterns of lung tumor tissue and nonmalignant tissue at the level of individual glycan structures using nLC-chip-TOF-MS. Using tissue samples from 42 lung adenocarcinoma patients, 29 differentially expressed (FDR < 0.05) glycan structures were identified. The levels of several oligomannose type glycans were upregulated in tumor tissue. Furthermore, levels of fully galactosylated glycans, some of which were of the hybrid type and mostly without fucose, were decreased in cancerous tissue, whereas levels of non- or low-galactosylated glycans mostly with fucose were increased. To further assess the regulation of the altered glycosylation, the glycomics data was compared to publicly available gene expression data from lung adenocarcinoma tissue compared to nonmalignant lung tissue. The results are consistent with the possibility that the observed N-glycan changes have their origin in differentially expressed glycosyltransferases. These results will be used as a starting point for the further development of clinical glycan applications in the fields of imaging, drug targeting, and biomarkers for lung cancer.

Comparative proteome analysis across non-small cell lung cancer cell lines

Non-small cell lung cancer (NSCLC) cell lines are widely used model systems to study molecular aspects of lung cancer. Comparative and in-depth proteome expression data across many NSCLC cell lines has not been generated yet, but would be of utility for the investigation of candidate targets and markers in oncogenesis. We employed a SILAC reference approach to perform replicate proteome quantifications across 23 distinct NSCLC cell lines. On average, close to 4000 distinct proteins were identified and quantified per cell line. These included many known targets and diagnostic markers, indicating that our proteome expression data represents a useful resource for NSCLC pre-clinical research. To assess proteome diversity within the NSCLC cell line panel, we performed hierarchical clustering and principal component analysis of proteome expression data. Our results indicate that general proteome diversity among NSCLC cell lines supersedes potential effects common to K-Ras or epidermal growth factor receptor (EGFR) oncoprotein expression. However, we observed partial segregation of EGFR or KRAS mutant cell lines for certain principal components, which reflected biological differences according to gene ontology enrichment analyses. Moreover, statistical analysis revealed several proteins that were significantly overexpressed in KRAS or EGFR mutant cell lines.

Investigation of metabolomic blood biomarkers for detection of adenocarcinoma lung cancer

BACKGROUND

Untargeted metabolomics was used in case-control studies of adenocarcinoma (ADC) lung cancer to develop and test metabolite classifiers in serum and plasma as potential biomarkers for diagnosing lung cancer.

METHODS

Serum and plasma were collected and used in two independent case-control studies (ADC1 and ADC2). Controls were frequency matched for gender, age, and smoking history. There were 52 adenocarcinoma cases and 31 controls in ADC1 and 43 adenocarcinoma cases and 43 controls in ADC2. Metabolomics was conducted using gas chromatography time-of-flight mass spectrometry. Differential analysis was performed on ADC1 and the top candidates (FDR < 0.05) for serum and plasma used to develop individual and multiplex classifiers that were then tested on an independent set of serum and plasma samples (ADC2).

RESULTS

Aspartate provided the best accuracy (81.4%) for an individual metabolite classifier in serum, whereas pyrophosphate had the best accuracy (77.9%) in plasma when independently tested. Multiplex classifiers of either 2 or 4 serum metabolites had an accuracy of 72.7% when independently tested. For plasma, a multimetabolite classifier consisting of 8 metabolites gave an accuracy of 77.3% when independently tested. Comparison of overall diagnostic performance between the two blood matrices yielded similar performances. However, serum is most ideal given higher sensitivity for low-abundant metabolites.

CONCLUSION

This study shows the potential of metabolite-based diagnostic tests for detection of lung adenocarcinoma. Further validation in a larger pool of samples is warranted.

IMPACT

These biomarkers could improve early detection and diagnosis of lung cancer.

Oncogenic miR-23a in Pancreatic Ductal Adenocarcinogenesis Via Inhibiting APAF1

BACKGROUND

miR-23a, which participates in invasion of pancreatic ductal adenocarcinoma cells into the mesothelial barrier, is a critical regulator in many cancers. It, however, is still unknown whether miR-23a regulates pancreatic cell proliferation and apoptosis or not.

AIMS

We sought to investigate the role of miR-23a in regulation of pancreatic cell proliferation and apoptosis.

METHODS

miRNA, mRNA, and protein expressions were determined by qRT-PCR and Western blot, respectively. Dual-luciferase reporter assay was used in detection for binding ability of miR-23a to APAF1. Ectopic miR-23a and APAF 1 were introduced to pancreatic cells, and their roles in proliferation and apoptosis were detected by MTT, colony formation, and apoptosis assays, respectively.

RESULTS

Up-regulation of miR-23a and down-regulation of APAF 1 were found in pancreatic ductal cancer, respectively. miR-23a significantly inhibited the luciferase activity by targeting APAF 1 3'UTR. Ectopic miR-23a significantly suppressed the APAF 1 gene expression in pancreatic cancer cells. Similar to siAPAF1, miR-23a significantly promoted pancreatic cancer cell proliferation and repressed apoptosis. Furthermore, miR-23a inhibitor and exogenous APAF 1 could recover the effects.

CONCLUSIONS

It is suggested that miR-23a, acting as an oncogenic regulator by directly targeting APAF 1 in pancreatic cancer, is a useful potential biomarker in diagnosis and treatment of pancreatic cancer.

Oncogenic miR-23a in Pancreatic Ductal Adenocarcinogenesis Via Inhibiting APAF1

BACKGROUND

miR-23a, which participates in invasion of pancreatic ductal adenocarcinoma cells into the mesothelial barrier, is a critical regulator in many cancers. It, however, is still unknown whether miR-23a regulates pancreatic cell proliferation and apoptosis or not.

AIMS

We sought to investigate the role of miR-23a in regulation of pancreatic cell proliferation and apoptosis.

METHODS

miRNA, mRNA, and protein expressions were determined by qRT-PCR and Western blot, respectively. Dual-luciferase reporter assay was used in detection for binding ability of miR-23a to APAF1. Ectopic miR-23a and APAF 1 were introduced to pancreatic cells, and their roles in proliferation and apoptosis were detected by MTT, colony formation, and apoptosis assays, respectively.

RESULTS

Up-regulation of miR-23a and down-regulation of APAF 1 were found in pancreatic ductal cancer, respectively. miR-23a significantly inhibited the luciferase activity by targeting APAF 1 3'UTR. Ectopic miR-23a significantly suppressed the APAF 1 gene expression in pancreatic cancer cells. Similar to siAPAF1, miR-23a significantly promoted pancreatic cancer cell proliferation and repressed apoptosis. Furthermore, miR-23a inhibitor and exogenous APAF 1 could recover the effects.

CONCLUSIONS

It is suggested that miR-23a, acting as an oncogenic regulator by directly targeting APAF 1 in pancreatic cancer, is a useful potential biomarker in diagnosis and treatment of pancreatic cancer.

Potential biomarkers for lung cancer screening

Notwithstanding the encouraging results of the National Lung Screening Trial (NLST) the scientific community still debates on the cost-benefit profile of low dose computed tomography (LDCT) lung cancer screening. Several major concerns regard how to identify subjects at high risk of developing lung cancer, the optimal diagnostic algorithm, the management of lung nodules and the high false positive rates. The use of complementary biomarkers would be a useful strategy for dealing with most of these issues. This short review will focus on candidates' biomarkers circulating in serum or plasma that already reached an advanced validation phase also in LDCT lung cancer screening series. The biomarkers presented below are examples of the value of searching candidates by looking not only to the tumor itself but also to the interplay between the tumor and the host in order to identify early changes related to the biological reactivity of the host to a developing cancer.

Plasma levels of heat shock protein 90 alpha associated with lung cancer development and treatment responses

PURPOSE

Altered expression of heat shock protein 90 alpha (Hsp90α) was associated with tumor development, progression, and metastasis. This study explored plasma levels of Hsp90α protein in patients with lung cancer and other controls to assess its diagnostic value and monitor treatment responses for patients with lung cancer.

EXPERIMENTAL DESIGN

A total of 2,247 individuals were recruited and assigned into two cohorts as static and dynamic groups. ELISA analysis and confirmation of plasma Hsp90α protein levels for association with tumor stages and treatment responses, respectively, were performed.

RESULTS

The average plasma levels of Hsp90α protein in patients with lung cancer were significantly higher than in healthy controls (P < 0.0001). Plasma levels of Hsp90α protein in patients with advanced lung cancer (stage III-IV) were higher than in patients with early-stage lung cancer (stage I-II; P < 0.001). Using a cutoff value of 56.33 ng/mL to separate lung cancer from other controls, the sensitivity and specificity reached 72.18% (95% CI, 0.695-0.749) and 78.70% (95% CI, 0.761-0.813), respectively. To confirm the different levels in the second cohort, plasma levels of Hsp90α protein showed a statistically significant difference between preoperative and postoperative patients in surgical patient groups (P < 0.007). There was also a statistically significant difference between the disease progressive group and stable disease group, with regard to partial response after chemotherapy (P < 0.0001).

CONCLUSIONS

This study demonstrated that plasma Hsp90α protein levels are useful as a diagnostic biomarker in lung cancer and predict the responses of patients with lung cancer to chemotherapy.

Multicenter evaluation of a new progastrin-releasing peptide (ProGRP) immunoassay across Europe and China

BACKGROUND

We performed a multicenter evaluation of the Elecsys® progastrin-releasing peptide (ProGRP) immunoassay in Europe and China.

METHODS

The assay was evaluated at three European and two Chinese sites by imprecision, stability, method comparison and differentiation potential in lung cancer.

RESULTS

Intermediate imprecision across five analyte concentrations ranged from 2.2% to 6.0% coefficient of variation. Good stability for plasma and serum samples was shown for various storage conditions. There was excellent correlation between the Elecsys® and ARCHITECT assays in plasma (slope 1.02, intercept -2.72pg/mL). The Elecsys® assay also showed good correlation between serum and plasma samples (slope 0.93, intercept 2.35pg/mL; correlation coefficient 0.97). ProGRP differentiated small-cell and non-small-cell lung cancer (NSCLC; area under the curve 0.90, 95% CI 0.87-0.93; 78.3% sensitivity, 95% specificity; at 84pg/mL), with no relevant effects of ethnicity, age, gender or smoking. Median ProGRP concentrations were low in benign diseases (38pg/mL), other malignancies (40pg/mL) or NSCLC (39pg/mL), except chronic kidney disease above stage 3 (>100pg/mL).

CONCLUSIONS

Increased stability of the Elecsys® ProGRP assay in serum and plasma offers clear benefits over existing assays. This first evaluation of a ProGRP assay in China demonstrated comparable differentiation potential among different ethnicities.

Role of microRNAs in malignant mesothelioma

Malignant mesothelioma (MM) is an aggressive tumor, mainly derived from the pleura, which is predominantly associated with exposure to asbestos fibers. The prognosis of MM patients is particularly severe, with a median survival of approximately 9-12 months and latency between exposure and diagnosis ranging from 20-50 years (median 30 years). Emerging evidence has demonstrated that tumor aggressiveness is associated with genome and gene expression abnormalities; therefore, several studies have recently focused on the role of microRNAs (miRNAs) in MM tumorigenesis. miRNAs are small non-protein coding single-stranded RNAs (17-22 nucleotides) involved in numerous cellular processes that negatively regulate gene expression by modulating the expression of downstream target genes. miRNAs are often deregulated in cancer; in particular, the differential miRNA expression profiles of MM cells compared to unaffected mesothelial cells have suggested potential roles of miRNAs as either oncogenes or tumor suppressor genes in MM oncogenesis. In this review, the mechanism of MM carcinogenesis was evaluated through the analysis of the published miRNA expression data. The roles of miRNAs as diagnostic biomarkers and prognostic factors for potential therapeutic strategies will be presented and discussed.

Biomolecular and clinical practice in malignant pleural mesothelioma and lung cancer: what thoracic surgeons should know

Today, molecular-profile-directed therapy is a guiding principle of modern thoracic oncology. The knowledge of new biomolecular technology applied to the diagnosis, prognosis, and treatment of lung cancer and mesothelioma should be part of the 21st century thoracic surgeons' professional competence. The European Society of Thoracic Surgeons (ESTS) Biology Club aims at providing a comprehensive insight into the basic biology of the diseases we are treating. During the 2013 ESTS Annual Meeting, different experts of the field presented the current knowledge about diagnostic and prognostic biomarkers in malignant pleural mesothelioma including new perspectives as well as the role and potential application of microRNA and genomic sequencing for lung cancer, which are summarized in the present article.

Evaluation of long noncoding RNA MALAT1 as a candidate blood-based biomarker for the diagnosis of non-small cell lung cancer

BACKGROUND

The long noncoding RNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) is described as a potential biomarker for NSCLC (non-small cell lung cancer). Diagnostic biomarkers need to be detectable in easily accessible body fluids, should be characterized by high specificity, sufficient sensitivity, and robustness against influencing factors. The aim of this study was to evaluate the performance of MALAT1 as a blood based biomarker for NSCLC.

RESULTS

MALAT1 was shown to be detectable in the cellular fraction of peripheral human blood, showing different expression levels between cancer patients and cancer-free controls. For the discrimination of NSCLC patients from cancer-free controls a sensitivity of 56% was calculated conditional on a high specificity of 96%. No impact of tumor stage, age, gender, and smoking status on MALAT1 levels could be observed, but results based on small numbers.

CONCLUSIONS

The results of this study indicate that MALAT1 complies with key characteristics of diagnostic biomarkers, i.e., minimal invasiveness, high specificity, and robustness. Due to its relatively low sensitivity MALAT1 might not be feasible as a single biomarker for the diagnosis of NSCLC in the cellular fraction of blood. Alternatively, MALAT1 might be applicable as a complementary biomarker within a panel in order to improve the entire diagnostic performance.

Research status and funding trends of lung cancer biomarkers

Lung cancer is one of malignant tumors with the highest morbidity and mortality in the world. At present, research of early diagnosis, treatment, prognosis, and metastasis associated biomarkers is most active. This article reviewed the research status of lung cancer biomarkers and analyzed the funding situation in the field of lung cancer markers in recent 10 years in China and abroad, to provide a reference for the future basic and clinical translational research of lung cancer biomarkers.