Biomarkers of gastric cancer: current advancement

Expression characteristics and biological functions of CGB5 gene in gastric cancer

OBJECTIVE

The chorionic gonadotropin (CG) subunit beta 5 (CGB5) gene is a member of the glycoprotein hormone β chain family, encoding the β5 subunit of CG, which has been shown to promote tumorigenesis and induce proliferation in various types of cancer including gastric cancer (GC). However, the mechanistic role of CGB5 in GC has not been fully elucidated. Therefore, this study investigated relevant genes that regulate GC through bioinformatics analysis.

METHODS

Immunohistochemistry, immunofluorescence, and western blot (WB) detection methods were appropriately used to evaluate the expression pattern and clinical significance of CGB5 in 100 Chinese GC patients that were recruited from the Gaochun People's Hospital. The effect of small interfering ribonucleic acid (siRNA) on apoptosis, migration, and invasion of GC cells was investigated in vitro. Three-dimensional tumor spheres of these two types of GC cells (NCI-N87 cells and MKN45 cells) were constructed before investigation of the Calcein acetoxymethyl ester (AM)/ Propidium iodide (PI) staining, flow cytometric apoptosis, and apoptotic-related protein content of the tumor spheres after siRNA inhibition of CGB5 expression.

RESULTS

It was observed that compared with adjacent normal gastric tissue, expression of CGB5 was significantly upregulated in GC tissue. The siRNA inhibited CGB5 expression in two GC cell lines (NCI-N87 cells and MKN45 cells). Also, it was discovered that CGB5 highly correlated with microsatellite instability (MSI) and immune cell activity in GC, thus revealing the greater research value of CGB5 gene. More importantly, CGB5 siRNA could inhibit invasion and migration of tumor cells, induce apoptosis of GC cells and GC tumor spheres, as well as the mechanism relating to regulation of apoptosis associated gene expression. Overall, the findings suggest that CGB5 may play a crucial role in the development of GC carcinogenesis. Thus, this research may contribute to design of potential drug targets for treatment of GC.

Prognostic value and therapeutic efficacy of interstitial circulating tumor cells in patients with advanced gastric cancer

BACKGROUND

The high mortality rate and recurrence/metastasis remain major challenges in the clinical management of gastric cancer (GC) patients. To optimize treatment stratification and management, there is an urgent need for efficient and non-invasive biomarkers. A meta-analysis on the prognostic role of circulating tumor cells (CTCs) in GC revealed a strong association between CTCs and patient prognosis. Among CTC subtypes, Interstitial CTCs (I-CTCs) exhibited the strongest invasiveness. This study innovatively investigated the expression profile of I-CTCs in advanced GC patients to evaluate their clinical utility.

AIM

To evaluate the clinical utility of I-CTCs as a non-invasive prognostic biomarker in advanced GC. To investigate the correlation between I-CTC count thresholds and chemotherapy efficacy in advanced GC patients. To establish the potential of preoperative I-CTC profiling for optimizing treatment stratification and postoperative surveillance.

METHODS

This study retrospectively analyzed 59 patients with advanced GC treated at the General Surgery Clinical Medical Center of Gansu Provincial Hospital between October 2019 and October 2020. The expression levels of I-CTCs were measured, and patient survival was monitored. The receiver operating characteristic curve was plotted to determine the optimal cut-off value for I-CTCs expression levels. Based on this cut-off value, 59 GC patients were grouped into positive and negative groups. The differences in clinicopathological characteristics between the two groups were analyzed. Patient survival was follow-up and recorded until October 2022. Plotting survival curves and performing univariate and multifactorial analyses of patient prognostic factors. The Kaplan-Meier method and Cox regression model were used, respectively.

RESULTS

A total of 59 patients were included in this study, and receiver operating characteristic curve analysis showed that the best cut-off value for I-CTCs was 5, with an area under the curve of 0.8356 (95% confidence interval: 0.7122-0.9590). The I-CTC count of ≥ 5 defines the positive group, while counts < 5 are classified as the negative group. Positive I-CTCs correlated with the degree of tumor differentiation and disease progression (P < 0.05). 16 of 59 patients received neoadjuvant chemotherapy. There were divided into progressive disease and disease control groups based on response to neoadjuvant chemotherapy. Patients in the I-CTCs-negative group had longer overall survival and disease-free survival than those in the positive group (P < 0.05). Multifactorial analysis revealed that I-CTCs positivity (HR = 13.323, 95% confidence interval: 1.675-105.962, P = 0.014) was an independent risk factor for survival in patients with advanced GC.

CONCLUSION

In patients with advanced GC, an I-CTC count of ≥ 5 is associated with both poor prognosis and reduced chemotherapy efficacy. I-CTCs may serve as a valuable preoperative biomarker for predicting the prognosis of advanced GC.

Epidemiology and prevention of gastric cancer: A comprehensive review

Gastric cancer is the third most deadly cancer worldwide. Helicobacter pylori (H. pylori) infection and specific diets are key risk factors for this illness, which is more frequent in various nations. Nearly half of the world's population, 4.4 billion, had H. pylori in 2015. East has a higher incidence rate than West. GC may spread to the liver, lungs, and bones. The majority of cases are adenocarcinomas (90%). In 2022, stomach cancer caused 968,784 new cases and 660,175 deaths worldwide. GC accounts for 7% of cancer diagnoses and 9% of deaths. The high death rate of gastric cancer highlights the need for preventative methods to improve prognosis. Early identification via biomarker screening, especially in high-risk groups, may improve outcomes and treatments.

Advances and challenges in gastric cancer testing: the role of biomarkers

Advances in the identification of molecular biomarkers and the development of targeted therapies have enhanced the prognosis of patients with advanced gastric cancer. Several established biomarkers have been widely integrated into routine clinical diagnostics of gastric cancer to guide personalized treatment. Human epidermal growth factor receptor 2 (HER2) was the first molecular biomarker to be used in gastric cancer with trastuzumab being the first approved targeted therapy for HER2-positive gastric cancer. Programmed death-ligand 1 positivity and microsatellite instability can guide the use of immunotherapies, such as pembrolizumab and nivolumab. More recently, zolbetuximab has been approved for patients with claudin 18.2-positive diseases in some countries. More targeted therapies, including savolitinib for MET-positive patients, are currently under clinical investigation. However, the clinical application of these diagnostic approaches could be hampered by many existing challenges, including invasive and costly sampling methods, variability in immunohistochemistry interpretation, high costs and long turnaround times for next-generation sequencing, the absence of standardized and clinically validated diagnostic cut-off values for some biomarkers, and tumor heterogeneity. Novel testing and analysis techniques, such as artificial intelligence-assisted image analysis and multiplex immunohistochemistry, and emerging therapeutic strategies, including combination therapies that integrate immune checkpoint inhibitors with targeted therapies, offer potential solutions to some of these challenges. This article reviews recent progress in gastric cancer testing, outlines current challenges, and explores future directions for biomarker testing and targeted therapy for gastric cancer.

PIWI-interacting RNA biomarkers in gastrointestinal disease

Detection and diagnosis of neoplastic and inflammatory gastrointestinal (GI) diseases are typically based on endoscopic and pathologic examination. In GI neoplastic diseases, diagnosis can be delayed due to the expense and invasive nature of this approach. Recently, PIWI-interacting RNAs (piRNAs), a group of small non-coding RNA molecules containing 24-31 nucleotides, have been thought to serve as biomarkers in many disease processes. For example, piRNAs are differentially expressed in GI cancer but their biologic role remains unclear. Using next-generation sequencing and microarray analyses, researchers have suggested that monitoring piRNAs could facilitate diagnosis and prognosis in GI disease. Herein, we reviewed the use of piRNAs in neoplastic, inflammatory, functional, and other diseases of the digestive system, which could shed new light on cancer screening, early detection, and personalized treatment.

Hp eradication decreased the expression level of PG II in patients of Hp negative with gastric intestinal metaplasia: a retrospective cross-sectional study

AIMS

This study aims to assess the serum levels of pepsinogen (PG)I, PG II, and gastrin (G17) in patients with gastric intestinal metaplasia (GIM) and evaluate their correlation with demographic characteristics.

METHODS

A total of 247 normal controls (NC) and 240 patients diagnosed with GIM were enrolled in this study. All participants underwent a gastroscopy procedure followed by pathological examination for diagnosis confirmation. The expression level of PGI, PG II, and G 17 was detected by fluorescence immunochromatography and Hp infection was detected by 13-carbon breath test. The demographic characteristics of the subjects were obtained through questionnaires.

RESULTS

Compared to the NC group, the GIM group showed a reduction in PG II expression level [10.71(6.40,16.89) VS 9.21(6.14,14.55), p = 0.010]. GIM patients had a higher prevalence of previous Hp eradication history (14.98% VS 23.75%, p = 0.014). The low PG II group exhibited a higher incidence rate of GIM compared to the high PG II group (54.10% VS 44.44%, p = 0 0.020). In the Hp-negative(Hp-) group, there was a decrease in both PGI and PG II expression levels when compared to the Hp-positive(Hp+) group [146.73 ± 78.53 VS 125.61 ± 68.75 and 10.19(7.27, 16.58) VS 7.36(5.62,12.53), p = 0.036 and p < 0.001]. Among patients without Hp eradication history, those with low PG II levels had a higher proportion of individuals with a history of Hp eradication than those with high PG II levels (29.31% VS 3.13%, p = 0.003). Additionally, within the subgroup that underwent Hp eradication, there was a decrease in PG II expression level compared to the subgroup without Hp eradication (6.16(5.13, 7.52) VS 8.73(5.67, 13.35), p = 0.041).

CONCLUSION

The prevalence of GIM was significantly associated with low levels of PG II. There was a significant association between HP eradication history and the prevalence of GIM. Hp eradication history resulted in reduced expression levels of PG II in Hp- GIM patients.

ILF2 protein is a promising serum biomarker for early detection of gastric cancer

BACKGROUND

Our previous small-sample study indicated that serum levels of interleukin enhancer binding factor 2 (ILF2) may have the potential for gastric cancer (GC) detection. The present study was conducted to further validate the diagnostic value of serum ILF2 protein for GC.

METHODS

Serum specimens and clinical data were collected from patients with GC (n = 99) or benign gastric disease (BGD) (n = 49) and healthy controls (HC) (n = 51). Serum ILF2 levels were measured using enzyme-linked immunosorbent assay. The diagnostic performance of ILF2 was evaluated using the area under the receiver operating characteristic curve (AUC). The independence and synergy of ILF2 in GC diagnosis were analyzed by modeling with conventional blood indicators.

RESULTS

The median serum ILF2 level was higher in the GC group (227.8ng/mL) than in the BGD group (72.0ng/mL) and the HC group (56.8ng/mL) (p < 0.001), and no significant difference across GC subgroups. The AUCs of ILF2 were 0.915 (95%CI 0.873-0.957) for GC vs. HC, 0.854 (95%CI 0.793-0.915) for GC vs. BGD, 0.885 (95%CI 0.841-0.929) for GC vs. BGD + HC, and 0.888 (95% CI 0.830-0.945) for TNM I stage GC vs. BGD + HC, outperforming conventional blood indicators (corresponding AUCs ranging from 0.641 to 0.782). ILF2 was independent of and synergistic with conventional blood indicators in GC diagnosis, and a simple diagnostic model based on ILF2 and red blood cell count improved the diagnostic performance, with positive rates of approximately 90% in various subgroups of GC.

CONCLUSIONS

Serum ILF2 protein is a novel and potential serum biomarker for the detection of GC, especially for early GC.

Plasma cell-free DNA methylome-based liquid biopsy for accurate gastric cancer detection

Early detection plays a critical role in mitigating mortality rates linked to gastric cancer. However, current clinical screening methods exhibit suboptimal efficacy. Methylation alterations identified from cell-free DNA (cfDNA) present a promising biomarker for early cancer detection. Our study focused on identifying gastric cancer-specific markers from cfDNA methylation to facilitate early detection. We enrolled 150 gastric cancer patients and 100 healthy controls in this study, and undertook genome-wide methylation profiling of cfDNA using cell-free methylated DNA immunoprecipitation and high-throughput sequencing. We identified 21 differentially methylated regions (DMRs) between the gastric tumor and nontumor groups using multiple algorithms. Subsequently, using the 21 DMRs, we developed a gastric cancer detection model by random forest algorithm in the discovery set, and validated the model in an independent set. The model was able to accurately discriminate gastric cancer with a sensitivity and specificity of 93.90% and 95.15% in the discovery set, respectively, and 88.38% and 94.23% in the validation set, respectively. These results underscore the efficacy and accuracy of cfDNA-derived methylation markers in distinguishing early stage gastric cancer. This study highlighted the significance of cfDNA methylation alterations in early gastric cancer detection.

Integrated gene-metabolite association network analysis reveals key metabolic pathways in gastric adenocarcinoma

Gastric adenocarcinoma is one of the most death cause cancers worldwide. Metabolomics is an effective approach for investigating the occurrence and progression of cancer and detecting prognostic biomarkers by studying the profiles of small bioactive molecules. To fully decipher the functional roles of the disrupted metabolites that modulate the cellular mechanism of gastric cancer, integrated gene-metabolite association network methods are critical to map the associations between metabolites and genes. In this study, we constructed a knowledge-based gene-metabolite association network of gastric cancer using the dysregulated metabolites and genes between gastric cancer patients and control group. The topological pathway analysis and gene-protein-metabolite-disease association analysis revealed four key gene-metabolite pathways which include eleven metabolites associated with modulated genes. The integrated gene-metabolite association network enables mechanistic investigation and provides a comprehensive overview regarding the investigation of molecular mechanisms of gastric cancer, which facilitates the in-depth understanding of metabolic biomarker roles in gastric cancer.

Immunotherapy Based on Immune Checkpoint Molecules and Immune Checkpoint Inhibitors in Gastric Cancer-Narrative Review

Due to its rapid progression to advanced stages and highly metastatic properties, gastric cancer (GC) is one of the most aggressive malignancies and the fourth leading cause of cancer-related deaths worldwide. The metastatic process includes local invasion, metastasis initiation, migration with colonisation at distant sites, and evasion of the immune response. Tumour growth involves the activation of inhibitory signals associated with the immune response, also known as immune checkpoints, including PD-1/PD-L1 (programmed death 1/programmed death ligand 1), CTLA-4 (cytotoxic T cell antigen 4), TIGIT (T cell immunoreceptor with Ig and ITIM domains), and others. Immune checkpoint molecules (ICPMs) are proteins that modulate the innate and adaptive immune responses. While their expression is prominent on immune cells, mainly antigen-presenting cells (APC) and other types of cells, they are also expressed on tumour cells. The engagement of the receptor by the ligand is crucial for inhibiting or stimulating the immune cell, which is an extremely important aspect of cancer immunotherapy. This narrative review explores immunotherapy, focusing on ICPMs and immune checkpoint inhibitors in GC. We also summarise the current clinical trials that are evaluating ICPMs as a target for GC treatment.

Biomarker discovery and validation for gastrointestinal tumors: A comprehensive review of colorectal, gastric, and liver cancers

Gastrointestinal (GI) malignancies, encompassing gastric, hepatic, colonic, and rectal cancers, are prevalent forms of cancer globally and contribute substantially to cancer-related mortality. Although there have been improvements in methods for diagnosing and treating GI cancers, the chances of survival for these types of cancers are still extremely low. According to the World Cancer Research International Fund's most recent figures, stomach cancer was responsible for roughly one million deaths worldwide in 2020. This emphasizes the importance of developing more effective tools for detecting, diagnosing, and predicting the outcome of these cancers at an early stage. Biomarkers, quantitative indications of biological processes or disease states, have emerged as promising techniques for enhancing the diagnosis and prognosis of GI malignancies. Recently, there has been a considerable endeavor to discover and authenticate biomarkers for various GI cancers by the utilization of diverse methodologies, including genomics, proteomics, and metabolomics. This review provides a thorough examination of the current state of biomarker research in the field of gastrointestinal malignancies, with a specific emphasis on colorectal, stomach, and liver cancers. A thorough literature search was performed on prominent databases such as PubMed, Scopus, and Web of Science to find pertinent papers published until November, 2023 for the purpose of compiling this review. The diverse categories of biomarkers, encompassing genetic, epigenetic, and protein-based biomarkers, and their potential utility in the fields of diagnosis, prognosis, and treatment selection, are explored. Recent progress in identifying and confirming biomarkers, as well as the obstacles that persist in employing biomarkers in clinical settings are emphasized. The utilization of biomarkers in GI cancers has significant potential in enhancing patient outcomes. Ongoing research is expected to uncover more efficient biomarkers for the diagnosis and prognosis of these cancers.

Single-cell transcriptomic analysis reveals crucial oncogenic signatures and its associative cell types involved in gastric cancer

The intricate association of oncogenic markers negatively impacts accurate gastric cancer diagnosis and leads to the proliferation of mortality rate. Molecular heterogeneity is inevitable in determining gastric cancer's progression state with multiple cell types involved. Identification of pathogenic gene signatures is imperative to understand the disease's etiology. This study demonstrates a systematic approach to identifying oncogenic gastric cancer genes linked with different cell types. The raw counts of adjacent normal and gastric cancer samples are subjected to a quality control step. The dimensionality reduction and multidimensional clustering are performed using Principal Component Analysis (PCA) and Uniform Manifold Approximation and Projection (UMAP) techniques. The adjacent normal and gastric cancer sample cell clusters are annotated with the Human Primary Cell Atlas database using the "SingleR." Cellular state transition between the distinct groups is characterized using trajectory analysis. The ligand-receptor interaction between Vascular Endothelial Growth Factor (VEGF) and cell clusters unveils crucial molecular pathways in gastric cancer progression. Chondrocytes, Smooth muscle cells, and fibroblast cell clusters contain genes contributing to poor survival rates based on hazard ratio during survival analysis. The GC-related oncogenic signatures are isolated by comparing the gene set with the DisGeNET database. Twelve gastric cancer biomarkers (SPARC, KLF5, HLA-DRB1, IGFBP3, TIMP3, LGALS1, IGFBP6, COL18A1, F3, COL4A1, PDGFRB, COL5A2) are linked with gastric cancer and further validated through gene set enrichment analysis. Drug-gene interaction found PDGFRB, interacting with various anti-cancer drugs, as a potential inhibitor for gastric cancer. Further investigations on these molecular signatures will assist the development of precision therapeutics, promising longevity among gastric cancer patients.

Zinc Finger Proteins in the War on Gastric Cancer: Molecular Mechanism and Clinical Potential

According to the 2020 global cancer data released by the World Cancer Research Fund (WCRF) International, gastric cancer (GC) is the fifth most common cancer worldwide, with yearly increasing incidence and the second-highest fatality rate in malignancies. Despite the contemporary ambiguous molecular mechanisms in GC pathogenesis, numerous in-depth studies have demonstrated that zinc finger proteins (ZFPs) are essential for the development and progression of GC. ZFPs are a class of transcription factors with finger-like domains that bind to Zn²⁺ extensively and participate in gene replication, cell differentiation and tumor development. In this review, we briefly outline the roles, molecular mechanisms and the latest advances in ZFPs in GC, including eight principal aspects, such as cell proliferation, epithelial-mesenchymal transition (EMT), invasion and metastasis, inflammation and immune infiltration, apoptosis, cell cycle, DNA methylation, cancer stem cells (CSCs) and drug resistance. Intriguingly, the myeloid zinc finger 1 (MZF1) possesses reversely dual roles in GC by promoting tumor proliferation or impeding cancer progression via apoptosis. Therefore, a thorough understanding of the molecular mechanism of ZFPs on GC progression will pave the solid way for screening the potentially effective diagnostic indicators, prognostic biomarkers and therapeutic targets of GC.