Genomewide Expression Profiling Identifies a Novel miRNA-Based Signature for the Detection of Peritoneal Metastasis in Patients With Gastric Cancer.Ann Surg. 2019;. [PMID: 31663973 DOI: 10.1097/SLA.0000000000003647]

Targeting non-coding RNAs as a promising biomarker in peritoneal metastasis: Background, mechanism, and therapeutic approach

Peritoneal metastasis (PM) pathophysiology is complex and not fully understood. PM, originating from gastrointestinal (GI) cancer, is a condition that significantly worsens patient prognosis due to its complex nature and limited treatment options. The non-coding RNAs (ncRNAs) have been shown to play pivotal roles in cancer biology, influencing tumorigenesis, progression, metastasis, and therapeutic resistance. Increasing evidence has demonstrated the regulatory functions of different classes of ncRNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in PM. Identifying biomarkers for early detection of PM is a crucial step towards improving patient outcomes, and how ncRNA profiles correlate with survival rates, response to therapy, and recurrence risks have raised much attention in recent years. Additionally, exploring innovative therapeutic approaches utilizing ncRNAs, such as targeted therapy and gene silencing, may offer new horizons in treating this dire condition. Recent advances in systemic treatments and the development of novel loco-regional therapies have opened doors to multimodal treatment approaches. Radical surgeries combined with hyperthermic intraperitoneal chemotherapy (HIPEC) have shown promising results, leading to extended patient survival. Current research is focused on the molecular characterization of PM, which is crucial for early detection and developing future therapeutic strategies. By summarizing the latest findings, this study underscores the transformative potential of ncRNAs in enhancing the diagnosis, prognosis, and treatment of PM in GI cancer, paving the way for more personalized and effective clinical strategies.

Integration of pan-omics technologies and three-dimensional in vitro tumor models: an approach toward drug discovery and precision medicine

Despite advancements in treatment protocols, cancer is one of the leading cause of deaths worldwide. Therefore, there is a need to identify newer and personalized therapeutic targets along with screening technologies to combat cancer. With the advent of pan-omics technologies, such as genomics, transcriptomics, proteomics, metabolomics, and lipidomics, the scientific community has witnessed an improved molecular and metabolomic understanding of various diseases, including cancer. In addition, three-dimensional (3-D) disease models have been efficiently utilized for understanding disease pathophysiology and as screening tools in drug discovery. An integrated approach utilizing pan-omics technologies and 3-D in vitro tumor models has led to improved understanding of the intricate network encompassing various signalling pathways and molecular cross-talk in solid tumors. In the present review, we underscore the current trends in omics technologies and highlight their role in understanding genotypic-phenotypic co-relation in cancer with respect to 3-D in vitro tumor models. We further discuss the challenges associated with omics technologies and provide our outlook on the future applications of these technologies in drug discovery and precision medicine for improved management of cancer.

Prognostic value of moderate or massive ascites in patients with advanced gastric cancer

Advanced gastric cancer is a highly aggressive malignancy. The available literature does not provide the prognostic value of ascites based on their degree, because most clinical trials exclude patients who present with massive ascites. Therefore, this study examined whether the presence or degree of ascites has a prognostic value in 124 patients with advanced gastric cancer. The degree of ascites was assessed using computed tomography and classified as none, small, moderate or massive. The overall survival (OS) was compared based on the presence or degree of ascites. Furthermore, a Cox proportional hazards analysis was performed to ascertain the predictors of OS. The cumulative 1-year and 2-year OS rates in patients without ascites were 43.5 and 20.2%, respectively, whereas those in patients with ascites were 29.1 and 13.6%, respectively (P=0.116). The cumulative 1-year and 2-year OS rates in patients without moderate or massive ascites were 39.5 and 20.9%, respectively; however, those in patients with moderate or massive ascites were 28.0 and 4.0%, respectively (P=0.027). Multivariate analysis showed that diffuse-type [hazard ratio (HR), 1.532; 95% confidence interval (CI), 1.002-2.343; P=0.049], moderate or massive ascites (HR, 2.153; 95% CI, 1.301-3.564; P=0.003) and chemotherapy (HR, 0.189; 95% CI, 0.101-0.352; P<0.001) were significant predictive factors of OS. In conclusion, the present study indicated that moderate or massive ascites may influence the OS of patients with advanced gastric cancer.

Single-cell RNA sequencing reveals the lineage of malignant epithelial cells and upregulation of TAGLN2 promotes peritoneal metastasis in gastric cancer

BACKGROUND

Peritoneal metastasis (PM) is an important factor contributing to poor prognosis in patients with gastric cancer (GC). Transcriptomic sequencing has been used to explore the molecular changes in metastatic cancers, but comparing the bulk RNA-sequencing data between primary tumors and metastases in PM studies is unreasonable due to the small proportion of tumor cells in PM tissues.

METHODS

We performed single-cell RNA-sequencing analysis on four gastric adenocarcinoma specimens, including one primary tumor sample (PT), one adjacent nontumoral sample (PN), one peritoneal metastatic sample (MT) and one normal peritoneum sample (MN), from the same patient. Pseudotime trajectory analysis was used to display the process by which nonmalignant epithelial cells transform into tumor cells and then metastasize to the peritoneum. Finally, in vitro and in vivo assays were used to validate one of the selected genes that promote peritoneal metastasis.

RESULTS

Single-cell RNA sequencing showed that a development curve was found from normal mucosa to tumor tissues and then into metastatic sites on peritoneum. TAGLN2 was found to trigger this metastasis process. The migration and invasion capability of GC cells were changed by downregulating and upregulating TAGLN2 expression. Mechanistically, TAGLN2 might modulate tumor metastasis via alterations in cell morphology and several signaling pathways, thus promoting epithelial-mesenchymal transition (EMT).

CONCLUSIONS

In summary, we identified and validated TAGLN2 as a novel gene involved in GC peritoneal metastasis. This study provided valuable insight into the mechanisms of GC metastasis and developed a potential therapeutic target to prevent GC cell dissemination.

Site-specific protein biomarkers in gastric cancer: a comprehensive review of novel biomarkers and clinical applications

INTRODUCTION

Gastric cancer (GC) is the fifth most common cancer and the fourth leading cause of cancer-related death worldwide, thus representing a significant global health burden. Early detection and monitoring of GC are essential to improve patient outcomes. While traditional cancer biomarkers such as carcinoembryonic antigen, carbohydrate antigen (CA) 19-9, and CA 72-4 are widely used, their limited sensitivity and specificity necessitate the exploration of alternative biomarkers.

AREAS COVERED

This review comprehensively analyzes the landscape of GC protein biomarkers identified from 2019 to 2022, with a focus on tissue, blood, urine, saliva, gastric juice, ascites, and exhaled breath as sample sources. We address the potential clinical applications of these biomarkers in early diagnosis, monitoring recurrence, and predicting survival and therapeutic response of GC patients.

EXPERT OPINION

The discovery of novel protein biomarkers holds great promise for improving the clinical management of GC. However, further validation in large, diverse cohorts is needed to establish the clinical utility of these biomarkers. Integrating these biomarkers with existing diagnostic and monitoring approaches will likely lead to improved personalized treatment plans and patient outcomes.

Identification and validation of crucial lnc-TRIM28-14 and hub genes promoting gastric cancer peritoneal metastasis

BACKGROUND

Gastric cancer peritoneal metastasis (GCPM) is an important cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs) play a key role in the regulation of GCPM, but the underlying mechanisms have not been elucidated.

METHODS

High-throughput RNA sequencing (RNA-seq) was performed on four groups of clinical specimens (non-metastatic gastric cancer primary tumor, adjacent normal gastric mucosal tissue, gastric cancer primary tumor with peritoneal metastasis and adjacent normal gastric mucosal tissue). After sequencing, many lncRNAs and mRNAs were screened for further Weighted Gene Co-expression Network Analysis (WGCNA). GCPM-related hub lncRNAs and genes were identified by cytoHubba and validated by Quantitative real-time PCR (qRT-PCR), Receiver operating characteristic curve (ROC) analysis and Kaplan-Meier survival analysis. GO, KEGG and GSEA showed GCPM-related pathways. Correlation analysis revealed the potential relationship between hub lncRNAs and genes.

RESULTS

By analyzing lncRNA expression data by WGCNA, we found that blue module was highly correlated with GCPM (r = 0.44, p = 0.04) and six lncRNAs involved in this module (DNM3OS, lnc-MFAP2-53, lnc-PPIAL4C-4, lnc-RFNG-1, lnc-TRIM28-14 and lnc-YARS2-4) were identified. We then performed qRT-PCR validation of gastric cancer specimens and found that the expression of lnc-RFNG-1 and lnc-TRIM28-14 was significantly increased in gastric cancer tissues with peritoneal metastasis. Kaplan-Meier survival analysis showed shorter overall survival time (OS) for gastric cancer patients with high expression of lnc-TRIM28-14. Receiver operating characteristic curve (ROC) analysis showed that lnc-TRIM28-14 could improve the sensitivity and specificity of GCPM diagnosis. In addition, we identified three key mRNAs (CD93, COL3A1 and COL4A1) associated with gastric cancer peritoneal metastasis through WGCNA analysis and clinical specimen validation. Moreover, there was a positive correlation between lnc-TRIM28-14 and the expression of CD93 and COL4A1 in gastric cancer peritoneal metastasis, suggesting a regulatory relationship between them. Subsequent GO, KEGG and GSEA analysis suggested that ECM-receptor interaction and focal adhesion were the hub pathways of GCPM.

CONCLUSION

In summary, lnc-RFNG-1, lnc-TRIM28-14, CD93, COL3A1 and COL4A1 could be novel tumor biomarkers and potential therapeutic targets for GCPM.

A miRNA-based gene therapy nanodrug synergistically enhances pro-inflammatory antitumor immunity against melanoma

MicroRNA (miRNA)-based gene therapy is a robust approach to treating human cancers. However, the low target specificity and safety issues associated with viral vectors have limited the clinical use of miRNA therapeutics. In the present study, we aimed to develop a biocompatible nanocarrier to deliver the tumor suppressor miR-30a-5p for gene therapy of ocular melanoma. The quasi-mesoporous magnetic nanospheres (MMNs) were prepared by polyelectrolytes-mediated self-assembling Fe₃O₄ nanocrystals; the cationic polymer capped quasi-mesoporous inner tunnels of the MMNs facilitate high miRNA loading and protect from nuclease degradation. Then, the outer layer of the MMNs was modified with a disulfide bond bridged very low molecular weight polyethyleneimine (PEI) network to form redox-responsive nanospheres (rMMNs) that enhance the miRNA payload and enable miRNA release under glutathione-dominant tumor microenvironment. The miR-30a-5p loaded rMMNs nanodrug (miR-30a-5p@rMMNs) upregulated miR-30a-5p level and inhibited malignant phenotypes of ocular melanoma by targeting the transcription factor E2F7 both in vitro and in vivo. Additionally, rMMNs act as an enhancer to increase cancer cell apoptosis by modulating M1-like macrophage polarization and activating Fenton reaction. Thus, the rMMNs is a promising miRNA carrier for gene therapy and could enhance pro-inflammatory immunity in melanoma and other cancers. STATEMENT OF SIGNIFICANCE: • miR-30a-5p@rMMNs inhibited malignant phenotypes of ocular melanoma both in vitro and in vivo. • The rMMNs promoted M1 macrophage polarization thus synergistically enhancing pro-inflammatory anti-tumor immunity against melanoma. • The rMMNs showed no obvious toxicity under the injection dose.

Application progress of liquid biopsy in gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors globally. Guiding the individualized treatment of GC is the focus of research. Obtaining representative biological samples to study the biological characteristics of GC is the focus of diagnosis and treatment of GC. Liquid biopsy technology can use high-throughput sequencing technology to detect biological genetic information in blood. Compared with traditional tissue biopsy, liquid biopsy can determine the dynamic changes of tumor. As a noninvasive auxiliary diagnostic method, liquid biopsy can provide diagnostic and prognostic information concerning the progression of the disease. Liquid biopsy includes circulating tumor cells, circulating tumor DNA, circulating tumor RNA, tumor educated platelets, exosomes, and cytokines. This article describes the classification of liquid biopsy and its application value in the occurrence, development, and therapeutic efficacy of GC.

Regulatory Roles of Noncoding RNAs in the Progression of Gastrointestinal Cancers and Health Disparities

Annually, more than a million individuals are diagnosed with gastrointestinal (GI) cancers worldwide. With the advancements in radio- and chemotherapy and surgery, the survival rates for GI cancer patients have improved in recent years. However, the prognosis for advanced-stage GI cancers remains poor. Site-specific GI cancers share a few common risk factors; however, they are largely distinct in their etiologies and descriptive epidemiologic profiles. A large number of mutations or copy number changes associated with carcinogenesis are commonly found in noncoding DNA regions, which transcribe several noncoding RNAs (ncRNAs) that are implicated to regulate cancer initiation, metastasis, and drug resistance. In this review, we summarize the regulatory functions of ncRNAs in GI cancer development, progression, chemoresistance, and health disparities. We also highlight the potential roles of ncRNAs as therapeutic targets and biomarkers, mainly focusing on their ethnicity-/race-specific prognostic value, and discuss the prospects of genome-wide association studies (GWAS) to investigate the contribution of ncRNAs in GI tumorigenesis.

Genome-Wide Analysis of microRNAs Identifies the Lipid Metabolism Pathway to Be a Defining Factor in Adipose Tissue From Different Sheep

microRNAs are a class of important non-coding RNAs, which can participate in the regulation of biological processes. In recent years, miRNA has been widely studied not only in humans and mice, but also in animal husbandry. However, compared with other livestock and poultry breeds, the study of miRNA in subcutaneous adipose tissue of sheep is not comprehensive. Transcriptome analysis of miRNAs in subcutaneous adipose tissue of Duolang sheep, and Small Tail Han sheep was performed using RNA-Seq technology. Differentially expressed miRNAs were screened between different breeds. Target genes were predicted, and then the joint analysis of candidate genes were conducted based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, the RNA-Seq data were verified by real-time quantitative polymerase chain reaction (qRT-PCR). Herein, we identified 38 differentially expressed miRNAs (9 novel miRNAs and 29 known miRNAs). In addition, a total of 854 target genes were predicted by miRanda software. GO and KEGG pathway analysis demonstrated that regulation of lipolysis in adipocytes plays a key role in the deposition of subcutaneous adipose tissue in Duolang sheep and Small Tail Han sheep. The miRNAs might regulate fat deposits by regulating genes involved in regulation of lipolysis in adipocytes. Specifically, NC_ 040278.1_ 37602, oar-mir-493-3p, NC_ 040278.1_ 37521 and NC_ 040255.1_ 11627 might target PTGS2, AKT2, AKT3, and PIK3CA, respectively, and then play critical regulatory role. In conclusion, all the results provide a good idea for further revealing the mechanism of subcutaneous adipose tissue deposition and improving the meat production performance of sheep, and lay a foundation for promoting the development of animal husbandry.

Single-cell RNA-seq dissecting heterogeneity of tumor cells and comprehensive dynamics in tumor microenvironment during lymph nodes metastasis in gastric cancer

Lymph node metastasis is the common metastasis route of gastric cancer. However, until now, heterogeneities of tumor cells and tumor microenvironment in primary tumors (PT) and metastatic lymph nodes (MLN) of gastric cancer (GC) remains uncharacterized. In this study, scRNA-seq was performed on tissues from PT and MLN of gastric cancer. Trajectory analysis and function enrichment analyses were conducted to decode the underlying mechanisms contributing to LN metastasis of gastric cancer. Heterogeneous composition of immune cells and distant intercellular interactions in PT and MLN were analyzed. Based on the generated single cell transcriptome profiles, dynamics of gene expressions in cancer cells between PT and MLN were characterized. Moreover, we reconstructed the developmental trajectory of GC cells' metastasis to LN and identified two sub-types of GC cells with distinct potentials of having malignant biological behaviors. We characterized the repression of neutrophil polarization associated genes, like LCN2, which would contribute to LN metastasis, and histochemistry experiments validated our findings. Additionally, heterogeneity in neutrophils, rather than macrophages, was characterized. Immune checkpoint associated interaction of SPP1 was found active in MLN. In conclusion, we decode the dynamics of tumor cells during LN metastasis in GC and to identify a sub-type of GC cells with potentials of LN metastasis. Our data indicated that the disordering the neutrophils polarization and maturation and the activation of immune checkpoint SPP1 might contribute to LN metastasis in GC, providing a novel insight on the mechanism and potential therapeutic targets of LN metastasis in GC. This article is protected by copyright. All rights reserved.

A novel 3'tRNA-derived fragment tRF-Val promotes proliferation and inhibits apoptosis by targeting EEF1A1 in gastric cancer

At present, it is commonly believed that tRFs and tiRNAs are formed by the specific and selective shear of tRNAs under certain pressure stimulation, rather than by random degradation of tRNA. tRFs and tiRNAs have been reported to contribute to the biological process of a variety of human cancers. However, the evidence for the mechanisms of tRFs and tiRNAs in the occurrence and development of gastric cancer (GC) is still insufficient. Here, we aimed to explore the carcinogenic roles of tRFs and tiRNAs in GC with RNA-sequencing technique, and found a novel 3'tRNA-derived fragment tRF-Val was significantly upregulated in GC tissues and cell lines. tRF-Val expression was positively correlated with tumor size and the depth of tumor invasion in GC tissues. Functionally, tRF-Val promoted proliferation and invasion, and inhibited apoptosis in GC cells. Mechanistically, tRF-Val directly bound to the chaperone molecule EEF1A1, mediated its transport into the nucleus and promoted its interaction with MDM2 (a specific p53 E3 ubiquitin ligase), thus inhibiting the downstream molecular pathway of p53 and promoting GC progression. These findings provided a new potential therapeutic target for GC and a new explanation for the occurrence of GC.

Patient-Level DNA Damage Repair Pathway Profiles and Anti-Tumor Immunity for Gastric Cancer

DNA damage repair (DDR) comprises the detection and correction of alterations in the chemical structure of DNA. The dysfunction of the DDR process has been determined to have important implications for tumor carcinogenesis, malignancy progression, treatment resistance, and prognosis assessment. However, the role of the DDR process in gastric cancer (GC) remains to be fully understood. Thus, a total of 2,019 GC samples from our hospital (Harbin Medical University Cancer Hospital in china) and 12 public data sets were included in our study. In this study, single-sample gene set enrichment analysis (ssGSEA) was used to generate the DDR pathway activity profiles of 8 DDR sub-pathways and identify a DDR pathway signature by combining the DDR sub-pathway gene sets. The DDR pathway profiling’s impacts on the clinical outcomes, biological functions, genetic variants, immune heterogeneity, and treatment responses were analyzed through multidimensional genomics and clinical data. The results demonstrate that the DDR pathway profiling was clearly distinguished between tumor and normal tissues. The DDR pathway profiling reveals patient-level variations, which may contribute to explaining the high heterogeneity of human GC for the biological features and treatment outcomes. Thus, tumors with low DDR signature scores were independently correlated with shorter overall survival time and significantly associated with mesenchymal, invasion, and metastasis phenotypes. The statistical model integrating this DDR pathway signature with other clinical predictors outperforms each predictor alone for predicting overall survival in discrimination, calibration, and net clinical benefit. Moreover, low DDR signature scores were tightly associated with genome stability, characterized by low tumor mutational burden (TMB) and low fractions of genome alteration. Furthermore, this study confirms that patients with low DDR pathway signature scores might not benefit from adjuvant chemotherapy and a monoclonal antibody directed against programmed cell death-1 ligand 1 (anti-PD1) therapy. These findings highlighted that the DDR pathway profiling confers important implications for patients with GC and provides insights into the specific clinical and molecular features underlying the DDR process, which may help to facilitate clinical management.

Mechanisms of Action And Clinical Implications of MicroRNAs in the Drug Resistance of Gastric Cancer

Gastric cancer (GC) is one of the most common malignant tumors of digestive systems worldwide, with high recurrence and mortality. Chemotherapy is still the standard treatment option for GC and can effectively improve the survival and life quality of GC patients. However, with the emergence of drug resistance, the clinical application of chemotherapeutic agents has been seriously restricted in GC patients. Although the mechanisms of drug resistance have been broadly investigated, they are still largely unknown. MicroRNAs (miRNAs) are a large group of small non-coding RNAs (ncRNAs) widely involved in the occurrence and progression of many cancer types, including GC. An increasing amount of evidence suggests that miRNAs may play crucial roles in the development of drug resistance by regulating some drug resistance-related proteins as well as gene expression. Some also exhibit great potential as novel biomarkers for predicting drug response to chemotherapy and therapeutic targets for GC patients. In this review, we systematically summarize recent advances in miRNAs and focus on their molecular mechanisms in the development of drug resistance in GC progression. We also highlight the potential of drug resistance-related miRNAs as biomarkers and therapeutic targets for GC patients.

Recent advances in blood-based and artificial intelligence-enhanced approaches for gastrointestinal cancer diagnosis

Gastrointestinal (GI) cancers are among the most common cancer types and leading causes of cancer-related deaths worldwide. There is a tremendous clinical need for effective early diagnosis for better healthcare of GI cancer patients. In this article, we provide a short overview of the recent advances in GI cancer diagnosis. In the first part, we discuss the applications of blood-based biomarkers, such as plasma circulating cell-free DNA, circulating tumor cells, extracellular vesicles, and circulating cell-free RNA, for cancer liquid biopsies. In the second part, we review the current trends of artificial intelligence (AI) for pathology image and tissue biopsy analysis for GI cancer, as well as deep learning-based approaches for purity assessment of tissue biopsies. We further provide our opinions on the future directions in blood-based and AI-enhanced approaches for GI cancer diagnosis, and we think that these fields will have more intensive integrations with clinical needs in the near future.

The Therapeutic Potential of MicroRNAs in Cancer: Illusion or Opportunity?

The functional involvement of microRNAs in human neoplasia has raised in the last years an increasing interest in the scientific community toward the potential application in clinics as therapeutic tools. Indeed, the possibility to modulate their expression to re-establish a lost equilibrium and counteract tumor growth and dissemination, and/or to improve responsiveness to standard therapies, is promising and fascinating. However, several issues need to be taken into account such as factors related to miRNA stability in the blood, tissue penetration and potential off-target effects, which might affect safety, tolerability and efficacy of an miRNA-based therapy. Here we describe the most relevant challenges related to miRNA-based therapy, review the delivery strategies exploited to date and the on-going clinical trials.

Molecular biology and immunology of gastric cancer peritoneal metastasis

Peritoneal metastases occur in 55-60% of patients with gastric cancer (GC) and are associated with a 2% 5-year overall survival rate. There are limited treatment options for these patients, and no targeted therapy or immunotherapy is available. Rational therapeutic targets remain to be found. In this review, we present the published literature and our own recent experience in molecular biology to identify important molecules and signaling pathways as well as cellular immunity involved in the peritoneal metastasis of GC. We also suggest potential novel strategies for improving the outcomes of GC patients with peritoneal metastasis.

MicroRNA expression profiling and target gene analysis in gastric cancer

This study aims to identify differentially expressed microRNAs (miRNAs) in gastric cancer by comparing gastric cancerous tissues with normal tissues, explore the potential roles.The miRNA expression microarray was employed on gastric cancer tissues, and apparently normal para-cancerous tissues from 3 patients undergoing radical surgery were matched. Quantitative RT-PCR was performed on the other 7 patients to validate the findings of the microarray. Furthermore, Gene Ontology (GO) analysis and enrichment analysis of KEGG Pathway were performed for 5 dysregulated candidate miRNAs, including 3 upregulated (miR-31-3p, miR-6736-3p, and miR-147b) and 2 downregulated (miR-3065-5p and miR-3921) miRNAs, in order to determine the role of miRNAs in tumorigenesis and development.Among these miRNAs, 17 miRNAs were found to be upregulated, and 19 miRNAs were found to be downregulated. The dysregulated expression of 5 candidate miRNAs, including miR-31-3p, miR-147b, miR-6736-3p, miR-3065-5p, and miR-3921, were verified by quantitative RT-PCR in the validation set. Among these miRNAs, miR-31-3p, miR-6736-3p, miR-3065-5p, and miR-3921 had 551 target gene intersections. The GO and KEGG Pathway analyses Revealed that miR-31-3p, miR-6736-3p, miR-3065-5p, and miR-3921 may participate in multiple pathophysiological processes, such as foreign substance metabolism and chemical carcinogenesis.The profile of differentially expressed miRNAs was successfully screened, and 4 miRNAs (i.e., miR-31-3p, miR-6736-3p, miR-3065-5p, and miR-3921) appeared to be involved in gastric carcinogenesis. These might serve as promising biomarkers for gastric cancer.

A MicroRNA Signature Identifies Pancreatic Ductal Adenocarcinoma Patients at Risk for Lymph Node Metastases

BACKGROUND & AIMS

Pancreatic ductal adenocarcinomas (PDACs) frequently metastasize to the lymph nodes; strategies are needed to identify patients at highest risk for lymph node metastases. We performed genome-wide expression profile analyses of PDAC specimens, collected during surgery or endoscopic ultrasound-guided fine-need aspiration (EUS-FNA), to identify a microRNA (miRNA) signature associated with metastasis to lymph nodes.

METHODS

For biomarker discovery, we analyzed miRNA expression profiles of primary pancreatic tumors from 3 public data sets (The Cancer Genome Atlas, GSE24279, and GSE32688). We then analyzed 157 PDAC specimens (83 from patients with lymph node metastases and 74 without) from Japan, collected from 2001 through 2017, for the training cohort and 107 PDAC specimens (63 from patients with lymph node metastases and 44 without) from a different medical center in Japan, from 2002 through 2016, for the validation cohort. We also analyzed samples collected by EUS-FNA before surgery from 47 patients (22 patients with lymph node metastases and 25 without; 17 for the training cohort and 30 from the validation cohort) and 62 specimens before any treatment from patients who received neoadjuvant chemotherapy (9 patients with lymph node metastasis and 53 without) for additional validation. Multivariate logistic regression analyses were used to evaluate the statistical differences in miRNA expression between patients with vs without metastases.

RESULTS

We identified an miRNA expression pattern associated with diagnosis of PDAC metastasis to lymph nodes. Using logistic regression analysis, we optimized and trained a 6-miRNA risk prediction model for the training cohort; this model discriminated patients with vs without lymph node metastases with an area under the curve (AUC) of 0.84 (95% confidence interval [CI], 0.77-0.89). In the validation cohort, the model identified patients with vs without lymph node metastases with an AUC of 0.73 (95% CI, 0.64-0.81). In EUS-FNA biopsy samples, the model identified patients with vs without lymph node metastases with an AUC of 0.78 (95% CI, 0.63-0.89). The miRNA expression pattern was an independent predictor of PDAC metastasis to lymph nodes in the validation cohort (odds ratio, 17.05; 95% CI, 2.43-119.57) and in the EUS-FNA cohort (95% CI, 0.65-0.87).

CONCLUSIONS

Using data and tumor samples from 3 independent cohorts, we identified an miRNA signature that identifies patients at risk for PDAC metastasis to lymph nodes. The signature has similar levels of accuracy in the analysis of resected tumor specimens and EUS-FNA biopsy specimens. This model might be used to select treatment and management strategies for patients with PDAC.

The potential of liquid biopsies in gastrointestinal cancer

BACKGROUND

Liquid biopsy is a novel approach for cancer diagnosis, the value of which in human gastrointestinal (GI) cancer has been confirmed by the previous studies. This article summarized the recent advances in liquid biopsy with a focus on novel technologies and the use of it in the screening, monitoring, and treatment of human GI cancer.

CONTENT

The concept of liquid biopsy was first used to define the detection of circulating tumor cells (CTCs) in cancer patients, and has been expanded to other biomarkers in blood and body fluids, such as circulating tumor DNA (ctDNA), extracellular vesicles (EVs) and circulating tumor RNA. If analyzed with proper and advanced techniques like next generation sequencing (NGS) or proteomics, liquid biopsies can open an enormous array of potential biomarkers. The amount changes of target biomarkers and the mutation of genetic materials provide quantitative and qualitative information, which can be utilized clinically for cancer diagnosis and disease monitoring.

SUMMARY

As a highly efficient, minimally invasive, and cost-effective approach to diagnose and evaluate prognosis of GI cancer, liquid biopsy has lots of advantages over traditional biopsy and is promising in future clinical utility. If the challenges are overcome in the near future, liquid biopsy will become a widely available and dependable option.