Biomarkers and molecular diagnosis of gastrointestinal and pancreatic neoplasms

Biomolecular sensors for advanced physiological monitoring

Body-based biomolecular sensing systems, including wearable, implantable and consumable sensors allow comprehensive health-related monitoring. Glucose sensors have long dominated wearable bioanalysis applications owing to their robust continuous detection of glucose, which has not yet been achieved for other biomarkers. However, access to diverse biological fluids and the development of reagentless sensing approaches may enable the design of body-based sensing systems for various analytes. Importantly, enhancing the selectivity and sensitivity of biomolecular sensors is essential for biomarker detection in complex physiological conditions. In this Review, we discuss approaches for the signal amplification of biomolecular sensors, including techniques to overcome Debye and mass transport limitations, and selectivity improvement, such as the integration of artificial affinity recognition elements. We highlight reagentless sensing approaches that can enable sequential real-time measurements, for example, the implementation of thin-film transistors in wearable devices. In addition to sensor construction, careful consideration of physical, psychological and security concerns related to body-based sensor integration is required to ensure that the transition from the laboratory to the human body is as seamless as possible.

Circulating exosomal microRNAs as potential prognostic biomarkers in gastrointestinal cancers: a systematic review and meta-analysis

BACKGROUND

Recent reports suggested that circulating exosomal microRNAs (exomiRs) may serve as non-invasive prediction biomarkers in gastrointestinal (GI) cancers, yet their clinicopathological and prognostic values need to be more clarified. Hence, the present meta-analysis was aimed to quantitatively assess the evidence regarding the association between circulating exomiRs and prognosis in GI cancer patients.

METHODS

A comprehensive search was carried out in prominent literature databases, including PubMed, ISI Web of Science, Scopus, and Embase. Odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CIs) were gathered to evaluate the strength of the association. The quality assessment was investigated through the Newcastle-Ottawa Scale (NOS) and publication bias via Eggers' test and funnel plots.

RESULTS

A total of 47 studies, comprising of 4881 patients, were considered eligible for this meta-analysis. Both up-regulated and down-regulated circulating exomiRs are significantly associated with differentiation (HR = 1.353, P = 0.015; HR = 1.504, P = 0.016), TNM stage (HR = 2.058, P < 0.001; HR = 2.745, P < 0.001), lymph node metastasis (HR = 1.527, P = 0.004; HR = 2.009, P = 0.002), distant metastasis (HR = 2.006, P < 0.001; HR = 2.799, P = 0.002), worse overall survival (OS) (HR = 2.053, P < 0.001; HR = 1.789, P = 0.001) and poorer disease/relapse/progression-free survival (DFS/RFS/PFS) (HR = 2.086, P < 0.001; HR = 1.607, P = 0.001) in GI cancer patients, respectively. In addition, subgroup analyses based on seven subcategories indicated the robustness of the association. The majority of findings were lack of publication bias except for the association between up-regulated exomiRs and OS or DFS/RFS/PFS and for the down-regulated exomiRs and TNM stage.

CONCLUSION

This study supports that up- and down-regulated circulating exomiRs are associated with poorer survival outcomes and could be served as potential prognostic biomarkers in GI cancers. Given the limitations of the current findings, such as significant heterogeneity, more investigations are needed to fully clarify the exomiRs prognostic role.

A Disintegrin and Metalloproteinase (ADAM) Family-Novel Biomarkers of Selected Gastrointestinal (GI) Malignancies?

The global burden of gastrointestinal (GI) cancers is expected to increase. Therefore, it is vital that novel biomarkers useful for the early diagnosis of these malignancies are established. A growing body of data has linked secretion of proteolytic enzymes, such as metalloproteinases (MMPs), which destroy the extracellular matrix, to pathogenesis of GI tumours. A disintegrin and metalloproteinase (ADAM) proteins belong to the MMP family but have been proven to be unique due to both proteolytic and adhesive properties. Recent investigations have demonstrated that the expression of several ADAMs is upregulated in GI cancer cells. Thus, the objective of this review is to present current findings concerning the role of ADAMs in the pathogenesis of GI cancers, particularly their involvement in the development and progression of colorectal, pancreatic and gastric cancer. Furthermore, the prognostic significance of selected ADAMs in patients with GI tumours is also presented. It has been proven that ADAM8, 9, 10, 12, 15, 17 and 28 might stimulate the proliferation and invasion of GI malignancies and may be associated with unfavourable survival. In conclusion, this review confirms the role of selected ADAMs in the pathogenesis of the most common GI cancers and indicates their promising significance as potential prognostic biomarkers as well as therapeutic targets for GI malignancies. However, due to their non-specific nature, future research on ADAM biology should be performed to elucidate new strategies for the diagnosis of these common and deadly malignancies and treatment of patients with these diseases.

Assessment on the lung injury of mice posed by airborne PM2.5 collected from developing area in China and associated molecular mechanisms by integrated analysis of mRNA-seq and miRNA-seq

Some epidemiological evidences showed exposure of airborne fine particulate matter (PM2.5) was associated with lung dysfunction. However, the adverse effects of PM2.5 from mid-scale city of China on the respiratory system were unknown. Correspondingly, the mechanisms, especially the epigenetic mechanism regulated by miRNAs, involved in PM2.5-induced lung injury has not been fully understood. In this study, male Balb/C mice were exposed to PM2.5 collected from mid-scale city (Baoji), China for 8 weeks (mean concentration 298.52 ± 25.86 μg/m3 at exposure chamber) using a whole-body exposure system. The carbon component was the main ingredient (45.80%) of PM2.5 followed by ions (43.19%). Meanwhile, the sum concentrations of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes (C18-C33) were 570.48 and 2029.13 ng/m3 in the exposure chamber, respectively. Obvious lung injury including pulmonary inflammation and fibrosis (p < 0.05 compared with the control) were found from PM2.5 exposure group determined by micro-CT and histopathological assays, respectively, suggesting the health risk posed by PM2.5 from mid-scale city of China should be concerned. The integrated analysis between mRNA-seq and miRNA-seq revealed the differentially expression genes in lung tissues were enriched in immune pathways including B cell receptor signaling (p = 0.078) and cell adhesion molecules (CAMs) (p = 0.0068). The expression profiles of the genes and corresponding mRNAs involved into the immune pathways determined by RT-qPCR analysis were consistent with them conducted by transcriptome. Moreover, the expression levels of the proteins (i.e., CD19, CD81, PIK3CD, and CD22) involved into B cell receptor signaling pathway from exposure group were 1.71- to 6.948- folds compared with the control, validating the results of the genes expression profiles. Further, canonical correlation analysis (CCA) and multiple correlation analysis between the target genes and components of PM2.5 documented the organic compounds (i.e., Benzo(a)pyrene (p = 0.012) and octadecane (p = 0.05)) and inorganic elements (i.e., Cl-, Ti, Al, and Zn) was the key environmental factors. Cd19, Pik3cd, and Cd8b1 might be the key genes for lung dysfunction induced by PM2.5 illuminated using interactive analysis (p < 0.05). This work for the first time showed the adverse effects of PM2.5 in mid-scale city in China on respiratory system should be concerned, and the associated epigenetic mechanism regulated by miRNA were revealed. These results may provide new insight into the development of future assessment on the air pollution associated respiratory disease.

Systematic review with meta-analysis: diagnostic performance of the combination of pepsinogen, gastrin-17 and anti-Helicobacter pylori antibodies serum assays for the diagnosis of atrophic gastritis

BACKGROUND

The combination of pepsinogen, gastrin-17 and anti-H. pylori antibodies serological assays (panel test) is a non-invasive tool for the diagnosis of atrophic gastritis. However, the diagnostic reliability of this test is still uncertain.

AIM

To assess the diagnostic performance of the serum panel test for the diagnosis of atrophic gastritis.

METHODS

Medline via PubMed, Embase, Scopus, Cochrane Library databases and abstracts of international conferences proceedings were searched from January 1995 to December 2016 using the primary keywords "pepsinogens," "gastrin," "atrophic gastritis," "gastric precancerous lesions." Studies were included if they assessed the accuracy of the serum panel test for the diagnosis of atrophic gastritis using histology according to the updated Sydney System as reference standard.

RESULTS

Twenty studies with a total of 4241 subjects assessed the performance of serum panel test for the diagnosis of atrophic gastritis regardless of the site in the stomach. The summary sensitivity was 74.7% (95% confidence interval (CI), 62.0-84.3) and the specificity was 95.6% (95%CI, 92.6-97.4). With a prevalence of atrophic gastritis of 27% (median prevalence across the studies), the negative predictive value was 91%. Few studies with small sample size assessed the performance of the test in detecting the site of atrophic gastritis.

CONCLUSIONS

The combination of pepsinogen, gastrin-17 and anti-H. pylori antibodies serological assays appears to be a reliable tool for the diagnosis of atrophic gastritis. This test may be used for screening subjects or populations at high risk of gastric cancer for atrophic gastritis; however, a cost-effectiveness analysis is needed.

Pathogenesis and risk factors for gastric cancer after Helicobacter pylori eradication

Helicobacter pylori (H. pylori) infection was thought to be the main cause of gastric cancer, and its eradication showed improvement in gastric inflammation and decreased the risk of gastric cancer. Recently, a number of studies reported the occurrence of gastric cancer after successful eradication. Patients infected with H. pylori, even after eradication, have a higher risk for the occurrence of gastric cancer when compared with uninfected patients. Metachronous gastric cancer occurs frequently following the endoscopic removal of early gastric cancer. These data indicate that metachronous cancer leads to the occurrence of gastric cancer even after successful eradication of H. pylori. The pathogenesis of this metachronous cancer remains unclear. Further research is needed to identify biomarkers to predict the development of metachronous gastric cancer and methods for gastric cancer screening. In this article, we review the role of the H. pylori in carcinogenesis and the histological and endoscopic characteristics and risk factors for metachronous gastric cancer after eradication. Additionally, we discuss recent risk predictions and possible approaches for reducing the risk of metachronous gastric cancer after eradication.

Molecular Mechanisms of Helicobacter pylori Pathogenesis

Helicobacter pylori infects 50% of mankind. The vast majority of H. pylori infection occurs in the developing countries where up to 80% of the middle-aged adults may be infected. Bacterial infection causes an inflammatory response that proceeds through a series of intermediated stages of precancerous lesions (gastritis, atrophy, intestinal metaplasia, and dysplasia). Among infected individuals, approximately 10% develops severe gastric lesions such as peptic ulcer disease, 1-3% progresses to gastric cancer (GC) with a low 5-year survival rate, and 0.1% develops mucosa-associated lymphoid tissue (MALT). GC is one of the most common cancer and the third leading cause of cancer-related deaths worldwide. In this review, we have summarized the most recent papers about molecular mechanisms of H. pylori pathogenesis. The main important steps of H. pylori infection such as adhesion, entry in epithelial gastric cells, activation of intracellular pathways until epigenetic modifications have been described.

1-butyltryptophan inhibits cell proliferation, migration, and invasion through the Akt pathway in human gastric cancer cells

We have previously demonstrated that novel 1-alkyl-tryptophan analogs 1-butyltryptophan (1-BT) can serve as a potential antitumor agent. However, the molecular mechanisms of 1-BT on cancer cells remain to be elucidated. The effect of 1-BT on cell proliferation was detected by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay and clone formation assay in SGC7901 and AGS cells. Cell cycle was determined by flow cytometry. Cell migration and invasion was determined by wound healing assay and transwell assay. The expression of cyclin-dependent kinase 4 (CDK4), cyclin D1, p16, PCNA, phosphorylated Akt, total Akt, phosphorylated ERK1/2, and total ERK1/2 was examined using Western blotting. Our data demonstrated that 1-BT inhibited cell proliferation in a dose- and time-dependent manner by the downregulation of expression of cyclin D1 and CDK4 and by the upregulation of p16 expression. The inhibition of cell growth was also demonstrated by cell cycle arrest at the G1/S phase. Furthermore, 1-BT inhibited cell migration and invasion in SGC7901 cells. In addition, we found that phosphorylated Akt was suppressed in 1-BT treated SGC7901 cells. Overexpression of activated Akt reversed the effects of 1-BT on cell migration and invasion in SGC7901 cells. These results indicated that 1-BT inhibited gastric cancer cells proliferation and migration through the Akt pathway, which has the potential clinical significance in the prevention and treatment of gastric cancer.

Metachronous gastric cancer after successful Helicobacter pylori eradication

The high incidence of gastric cancer in Japan initially resulted in establishment of a country-wide gastric cancer screening program to detect early and treatable cancers. In 2013 countrywide Helicobacter pylori (H. pylori) eradication was approved coupled with endoscopy to assess for the presence of chronic gastritis. Current data support the notion that cure of the infection in those with non-atrophic gastritis will prevent development of gastric cancer. However, while progression to more severe damage is halted in those who have already developed, atrophic gastritis/gastric atrophy remain at risk for subsequent development of gastric cancer. That risk is directly related to the extent and severity of atrophic gastritis. Methods to stratify cancer risk include those based on endoscopic assessment of the atrophic border, histologic grading, and non-invasive methods based on serologic testing of pepsinogen levels. Continued surveillance is required because those with atrophic gastritis/gastric atrophy retain considerable gastric cancer risk even after H. pylori eradication. Those who have already experienced a resectable early gastric cancer are among those at highest risk as metachronous lesions are frequent even after H. pylori eradication. We review the role of H. pylori and effect of H. pylori eradication indicating the incidence and the predictive factors on development of metachronous cancer after endoscopic therapy of early gastric cancer. Studies to refine risk markers to stratify for risk, surveillance methods, intervals, and duration after successful H. pylori eradication, and whether adjuvant therapy would change risk are needed.

Role of miR-191/425 cluster in tumorigenesis and diagnosis of gastric cancer

Gastric cancer (GC) is among the most frequent types of cancer worldwide. Therefore, understanding the biology of GC tumorigenesis is important for appropriate diagnosis and patient surveillance. The miR-191/425 cluster has been reported to be overexpressed in various human cancers, but the tumorigenic role and clinical significance of miR-191/425 overexpression in gastric carcinogenesis is currently undefined. In this study, the expression of miR-191 and miR-425 in GC tissue and serum was assessed, and the relationship between miRNA expression and clinicopathological data was analyzed. We found that miR-191 and miR-425 were both significantly increased in human GC tissues relative to adjacent normal controls. In addition, miR-191 levels correlated with GC tumor stage and metastatic state. Furthermore, the level of serum miR-191 was significantly higher in the GC group than in the control group when using serum miR-16 as an endogenous control. Finally, inhibition of miR-191 or miR-425 in the GC cell lines HGC-27 not only reduced cell proliferation and cell cycle progression but also impaired cell migration and invasion. Taken together, our results revealed the oncogenic roles of miR-191 and miR-425 in gastric carcinogenesis, and indicated the potential use of serum miR-191 as a novel and stable biomarker for GC diagnosis.

Identification of serum miRNAs as novel non-invasive biomarkers for detection of high risk for early gastric cancer

BACKGROUND

Many micro-RNAs (miRNAs) are differentially expressed in Helicobacter pylori-infected gastric mucosa and in gastric cancer tissue and previous reports have suggested the possibility of serum miRNAs as complementary tumour markers. The aim of the study was to investigate serum miRNAs and pepsinogen levels in individuals at high risk for gastric cancer both before and after H. pylori eradication.

METHODS

Patients with recent history of endoscopic resection for early gastric cancer and the sex- and age-matched controls were enrolled. Serum was collected from subjects before or after eradication and total RNA was extracted to analyse serum levels of 24 miRNAs. Serum pepsinogen (PG) I and II levels were measured using enzyme-linked immunosorbent assay kits.

RESULTS

Using miR-16 as an endogenous control, the relative levels of miR-106 and let-7d before and after H. pylori eradication and miR-21 after eradication were significantly higher in the high-risk group than in the controls. H. pylori eradication significantly decreased miR-106b levels and increased let-7d only in the control group. After eradication, the combination MiR-106b with miR-21 was superior to serum pepsinogen and the most valuable biomarker for the differentiating high-risk group from controls.

CONCLUSION

Serum miR-106b and miR-21 may provide a novel and stable marker of increased risk for early gastric cancer after H. pylori eradication.

Eradication of gastric cancer is now both possible and practical

In 1994, Helicobacter pylori was declared a human carcinogen. Evidence has now accumulated to show that at least 95% of gastric cancers are etiologically related to H. pylori. An extensive literature regarding atrophic gastritis and its effects on acid secretion, gastric microflora, and its tight association with gastric cancer has been rediscovered, confirmed, and expanded. Methods to stratify cancer risk based on endoscopic and histologic findings or serologic testing of pepsinogen levels and H. pylori testing have been developed producing practical primary and secondary gastric cancer prevention strategies. H. pylori eradication halts progressive mucosal damage. Cure of the infection in those with non-atrophic gastritis will essentially prevent subsequent development of gastric cancer. For all, the age-related progression in cancer risk is halted and likely reduced as eradication reduces or eliminates mucosal inflammation and reverses or reduces H. pylori-associated molecular events such aberrant activation-induced cytidine deaminase expression, double strand DNA breaks, impaired DNA mismatch repair and aberrant DNA methylation. Those who have developed atrophic gastritis/gastric atrophy however retain some residual risk for gastric cancer which is proportional to the extent and severity of atrophic gastritis. Primary and secondary cancer prevention starts with H. pylori eradication and cancer risk stratification to identify those at higher risk who should also be considered for secondary cancer prevention programs. Japan has embarked on population-wide H. pylori eradication coupled with surveillance targeted to those with significant remaining risk. We anticipate that countries with high gastric cancer burdens will follow their lead. We provide specific recommendations on instituting practical primary and secondary gastric cancer prevention programs as well identifying research needed to make elimination of gastric cancer both efficient and cost effective.

Aberrant methylation of RASGRF1 is associated with an epigenetic field defect and increased risk of gastric cancer

Aberrant DNA methylation is implicated in the epigenetic field defect seen in gastric cancer. Our aim in this study was to identify predictive biomarkers by screening for DNA methylation in noncancerous background gastric mucosa from patients with gastric cancer. Using methylated-CpG island amplification coupled with CpG island microarray (MCAM) analysis, we identified 224 genes that were methylated in the noncancerous gastric mucosa of patients with gastric cancer. Among them, RASGRF1 methylation was significantly elevated in gastric mucosa from patients with either intestinal or diffuse type gastric cancer, as compared with mucosa from healthy individuals (8.3% vs. 22.4%, P < 0.001; 8.3% vs. 19.4%, P < 0.001). RASGRF1 methylation was independent of mucosal atrophy and could be used to distinguish both serum pepsinogen test-positive [sensitivity, 70.0%; specificity, 86.7%; area under the receiver operator characteristic (ROC) curve, AUC, 0.763] and -negative patients with gastric cancer (sensitivity, 72.2%; specificity, 87.0%; AUC, 0.844) from healthy individuals. Ectopic expression of RASGRF1 suppressed colony formation and Matrigel invasion by gastric cancer cells, suggesting it may be involved in gastric tumorigenesis. Collectively, our data suggest that RASGRF1 methylation is significantly involved in an epigenetic field defect in the stomach, and that it could be a useful biomarker to identify individuals at high risk for gastric cancer.

A systematic comparison and evaluation of high density exon arrays and RNA-seq technology used to unravel the peripheral blood transcriptome of sickle cell disease

Background

Transcriptomic studies in clinical research are essential tools for deciphering the functional elements of the genome and unraveling underlying disease mechanisms. Various technologies have been developed to deduce and quantify the transcriptome including hybridization and sequencing-based approaches. Recently, high density exon microarrays have been successfully employed for detecting differentially expressed genes and alternative splicing events for biomarker discovery and disease diagnostics. The field of transcriptomics is currently being revolutionized by high throughput DNA sequencing methodologies to map, characterize, and quantify the transcriptome.

Methods

In an effort to understand the merits and limitations of each of these tools, we undertook a study of the transcriptome in sickle cell disease, a monogenic disease comparing the Affymetrix Human Exon 1.0 ST microarray (Exon array) and Illumina’s deep sequencing technology (RNA-seq) on whole blood clinical specimens.

Results

Analysis indicated a strong concordance (R = 0.64) between Exon array and RNA-seq data at both gene level and exon level transcript expression. The magnitude of differential expression was found to be generally higher in RNA-seq than in the Exon microarrays. We also demonstrate for the first time the ability of RNA-seq technology to discover novel transcript variants and differential expression in previously unannotated genomic regions in sickle cell disease. In addition to detecting expression level changes, RNA-seq technology was also able to identify sequence variation in the expressed transcripts.

Conclusions

Our findings suggest that microarrays remain useful and accurate for transcriptomic analysis of clinical samples with low input requirements, while RNA-seq technology complements and extends microarray measurements for novel discoveries.

A novel model might predict the risk of chronic atrophic gastritis: a multicenter prospective study in China

OBJECTIVE

To find a new way to predict the risk of chronic atrophic gastritis (CAG).

MATERIAL AND METHODS

All the participants received endoscopy and histological examination as well as a standard questionnaire. Multivariate analysis was performed by logistic regression to build the CAG risk model. The accuracy was evaluated by 1418 subjects recruited from six medical centers. 63 subjects received another endoscopy after 1-year follow-up and divided into three groups according to the comparison of the histological results (improved, no change and worse).

RESULTS

The model showed relatively good discrimination, with an AUROC of 0.888 (95% CI 0.852-0.925). A final probability cut-off score of 0.73 was used to predict the presence (>0.73) or absence of CAG (≤0.73). Sensitivity, specificity, PPV and NPV were 82.8%, 74.7%, 91.8% and 56%, respectively. The predicted results of 1418 subjects compared with the histological results were quite similar. There was a significant difference of the scores between three groups who were followed-up for 1 year (F = 3.248, p = 0.046). In multiple comparisons, a significant difference existed between Group A (the histological results had improved after 1-year follow-up) and Group C (the results were worse) (p = 0.019).

CONCLUSIONS

This is the first demonstration of the use of a mathematical model for CAG risk screening. Endoscopy should be recommended to those who are positive according to the model, to detect CAG early and conserve medical resources. In those who have a high-risk score, closer follow-up is needed.

Pancreatic cancer: translational research aspects and clinical implications

Despite improvements in surgical techniques and adjuvant chemotherapy, the overall mortality rates in pancreatic cancer have generally remained relatively unchanged and the 5-year survival rate is actually below 2%. This paper will address the importance of achieving an early diagnosis and identifying markers for prognosis and response to therapy such as genes, proteins, microRNAs or epigenetic modifications. However, there are still major hurdles when translating investigational biomarkers into routine clinical practice. Furthermore, novel ways of secondary screening in high-risk individuals, such as artificial neural networks and modern imaging, will be discussed. Drug resistance is ubiquitous in pancreatic cancer. Several mechanisms of drug resistance have already been revealed, including human equilibrative nucleoside transporter-1 status, multidrug resistance proteins, aberrant signaling pathways, microRNAs, stromal influence, epithelial-mesenchymal transition-type cells and recently the presence of cancer stem cells/cancer-initiating cells. These factors must be considered when developing more customized types of intervention ("personalized medicine"). In the future, multifunctional nanoparticles that combine a specific targeting agent, an imaging probe, a cell-penetrating agent, a biocompatible polymer and an anti-cancer drug may become valuable for the management of patients with pancreatic cancer.

Gastric cancer screening by combined assay for serum anti-Helicobacter pylori IgG antibody and serum pepsinogen levels - "ABC method"

The current status of screening for gastric cancer-risk (gastritis A, B, C, D) method using combined assay for serum anti-Helicobacter pylori (Hp) IgG antibody and serum pepsinogen (PG) levels, "ABC method", was reviewed and the latest results of our ongoing trial are reported. It was performed using the following strategy: Subjects were classified into 1 of 4 risk groups based on the results of the two serologic tests, anti-Hp IgG antibody titers and the PG I and II levels: Group A [Hp(-)PG(-)], infection-free subjects; Group B [Hp(+)PG(-)], chronic atrophic gastritis (CAG) free or mild; Group C [Hp(+)PG(+)], CAG; Group D [Hp(-)PG(+)]), severe CAG with extensive intestinal metaplasia. Continuous endoscopic follow-up examinations are required to detect early stages of gastric cancer. Asymptomatic Group A, which accounts for 50-80% of all the subjects may be excluded from the secondary endoscopic examination, from the viewpoint of efficiency. Hp-infected subjects should be administered eradication treatment aimed at the prevention of gastric cancer.