Biomarkers of gastric cancer: Current topics and future perspective

How to Best Exploit Immunotherapeutics in Advanced Gastric Cancer: Between Biomarkers and Novel Cell-Based Approaches

Despite extensive research efforts, advanced gastric cancer still has a dismal prognosis with conventional treatment options. Immune checkpoint inhibitors have revolutionized the treatment landscape for many solid tumors. Amongst gastric cancer subtypes, tumors with microsatellite instability and Epstein Barr Virus positive tumors provide the strongest rationale for responding to immunotherapy. Various predictive biomarkers such as mismatch repair status, programmed death ligand 1 expression, tumor mutational burden, assessment of tumor infiltrating lymphocytes and circulating biomarkers have been evaluated. However, results have been inconsistent due to different methodologies and thresholds used. Clinical implementation therefore remains a challenge. The role of immune checkpoint inhibitors in gastric cancer is emerging with data from monotherapy in the heavily pre-treated population already available and studies in earlier disease settings with different combinatorial approaches in progress. Immune checkpoint inhibitor combinations with chemotherapy (CT), anti-angiogenics, tyrosine kinase inhibitors, anti-Her2 directed therapy, poly (ADP-ribose) polymerase inhibitors or dual checkpoint inhibitor strategies are being explored. Moreover, novel strategies including vaccines and CAR T cell therapy are also being trialed. Here we provide an update on predictive biomarkers for response to immunotherapy with an overview of their strengths and limitations. We discuss clinical trials that have been reported and trials in progress whilst providing an account of future steps needed to improve outcome in this lethal disease.

Gastric Cancer: Advances in Carcinogenesis Research and New Therapeutic Strategies

Gastric cancer’s bad incidence, prognosis, cellular and molecular heterogeneity amongst others make this disease a major health issue worldwide. Understanding this affliction is a priority for proper patients’ management and for the development of efficient therapeutical strategies. This review gives an overview of major scientific advances, made during the past 5-years, to improve the comprehension of gastric adenocarcinoma. A focus was made on the different actors of gastric carcinogenesis, including, Helicobacter pylori cancer stem cells, tumour microenvironment and microbiota. New and recent potential biomarkers were assessed as well as emerging therapeutical strategies involving cancer stem cells targeting as well as immunotherapy. Finally, recent experimental models to study this highly complex disease were discussed, highlighting the importance of gastric cancer understanding in the hard-fought struggle against cancer relapse, metastasis and bad prognosis.

Treatment Strategies of Gastric Cancer-Molecular Targets for Anti-angiogenic Therapy: a State-of-the-art Review

Purpose

Recent studies have suggested that molecular targets for the anti-angiogenic therapy might constitute a basis for additional therapy in gastric cancer treatment. A vast number of molecules, receptors, pathways, specific interactions, and thus strategies that target gastric cancer angiogenesis specifically have been reported in numerous research articles and clinical trials.

Methods

We conducted a systematic literature review of molecularly targeted treatment strategies in gastric cancer on the following databases—PubMed, Google Scholar, and Scopus—on September 20, 2020. Multiple articles and evaluations were searched for studies reporting newly found and promising molecular anti-angiogenic therapy pathways. Eventually, 39 articles regarding the anti-angiogenic therapy in gastric cancer were included in the final analysis.

Results

As a consequence of the release of the pro-angiogenic molecules from the tumour cells, gastric cancer presents high angiogenic capability. Therefore, potential schemes for future treatment strategies include the decrease of the process ligands as well as the expression of their receptors. Moreover, the increase in the angiogenic inhibitor levels and direct aim for the inner walls of the endothelial cells appear as a promising therapeutic strategy. Beyond that, angiogenesis process inhibition seems to indirectly exaggerate the effects of chemotherapy in the considered patients.

Conclusions

The anti-angiogenic treatment in gastric cancer patients evaluates its significance especially in the early stages of the malignancy. The studies conducted so far show that most of the meaningful angiogenic factors and receptors with the potential molecular pathways should be further evaluated since they could potentially play a substantial role in future therapies.

The Extracellular Small Leucine-Rich Proteoglycan Biglycan Is a Key Player in Gastric Cancer Aggressiveness

Simple Summary

Approximately 80% of gastric cancer patients are diagnosed at advanced stages with an average five-year survival rate of less than 30%. Alterations of the extracellular matrix proteins have been largely demonstrated in all steps of the disease. Thus, studies for the identification of novel prognostic biomarkers and efficient therapeutic strategies are urgently needed. In this study, we report the oncogenic role of biglycan, an extracellular proteoglycan, in gastric carcinogenesis. Biglycan was able to modulate gastric cancer aggressive features as cell survival, migration, and angiogenesis. Additionally, high levels of biglycan expression correlates with tumorigenic gene signatures and they are associated with poor patient prognosis in advanced stages of the disease. These results point biglycan as a key player in gastric cancer aggressiveness and further studies should be done to investigate the therapeutic potential of biglycan to tackle gastric cancer progression.

Abstract

Biglycan (BGN gene), an extracellular proteoglycan, has been described to be associated with cancer aggressiveness. The purpose of this study was to clarify the clinical value of biglycan as a biomarker in multiple independent GC cohorts and determine the in vitro and in vivo role of biglycan in GC malignant features. We found that BGN is commonly over-expressed in all analyzed cohorts, being associated with disease relapse and poor prognosis in patients with advanced stages of disease. In vitro and in vivo experiments demonstrated that biglycan knock-out GC cells display major phenotypic changes with a lower cell survival, migration, and angiogenic potential when compared with biglycan expressing cells. Biglycan KO GC cells present increased levels of PARP1 and caspase-3 cleavage and a decreased expression of mesenchymal markers. Importantly, biglycan deficient GC cells that were supplemented with exogenous biglycan were able to restore biological features, such as survival, clonogenic and migratory capacities. Our in vitro and in vivo findings were validated in human GC samples, where BGN expression was associated with several oncogenic gene signatures that were associated with apoptosis, cell migration, invasion, and angiogenesis. This study provided new insights on biglycan role in GC that should be taken in consideration as a key cellular regulator with major impact in tumor progression and patients’ clinical outcome.

Immunopositivity for Siglec-15 in gastric cancer and its association with clinical and pathological parameters

The sialic acid-binding immunoglobulin-type lectin Siglec-15 is a promising target for cancer immunotherapy in several tumor types. The present study aimed to investigate Siglec-15 expression in gastric cancer (GC) patient tissues and to evaluate its clinical value. Siglec-15 expression was evaluated by immunohistochemistry in 71 patients. Siglec-15 staining was observed in tumor cells of 53 (74.64%) patients, with significant association with histologic classification and angiolymphatic invasion (p<0.05). Immunohistochemistry analysis also detected Siglec-15 in tumor-associated stroma cells (macrophages/myeloid cells). There was no significant association with outcome parameters. Siglec-15 expression in well differentiated histological GC tissues and in the tumor microenvironment are potential targets to be further investigated as a novel prognostic factor for GC.

STK31 upregulation is associated with chromatin remodeling in gastric cancer and induction of tumorigenicity in a xenograft mouse model

Pathological changes in the epigenetic landscape of chromatin are hallmarks of cancer. Our previous study showed that global methylation of promoters may increase or decrease during the transition from gastric mucosa to intestinal metaplasia (IM) to gastric cancer (GC). Here, CpG hypomethylation of the serine/threonine kinase STK31 promoter in IM and GC was detected in a reduced representation bisulfite sequencing database. STK31 hypomethylation, which resulted in its upregulation in 120 cases of primary GC, was confirmed. Using public genome-wide histone modification data, upregulation of STK31 promoter activity was detected in primary GC but not in normal mucosae, suggesting that STK31 may be repressed in gastric mucosa but activated in GC as a consequence of hypomethylation-associated chromatin remodeling. STK31 knockdown suppressed the proliferation, colony formation and migration activities of GC cells in vitro, whereas stable overexpression of STK31 promoted the proliferation, colony formation, and migration activities of GC cells in vitro and tumorigenesis in nude mice. Patients with GC in which STK31 was upregulated exhibited significantly shorter survival times in a combined cohort. Thus, activation of STK31 by chromatin remodeling may be associated with gastric carcinogenesis and also may help predict GC prognosis.

Clinical difference between fibroblast growth factor receptor 2 subclass, type IIIb and type IIIc, in gastric cancer

Fibroblast growth factor receptor 2 (FGFR2) has two isoforms: IIIb type and IIIc type. Clinicopathologic significance of these two FGFR2 subtypes in gastric cancer remains to be known. This study aimed to clarify the clinicopathologic difference of FGFR2IIIb and/or FGFR2IIIc overexpression. A total of 562 patients who underwent gastrectomy was enrolled. The expressions of FGFR2IIIb and FGFR2IIIc were retrospectively examined by immunohistochemistry or fluorescence in situ hybridization (FISH) using the 562 gastric tumors. We evaluated the correlation between clinicopathologic features and FGFR2IIIb overexpression and/or FGFR2IIIc overexpression in gastric cancer. FGFR2IIIb overexpression was observed in 28 cases (4.9%), and FGFR2IIIc overexpression was observed in four cases (0.7%). All four FGFR2IIIc cases were also positive for FGFR2IIIb, but not in the same cancer cells. FGFR2IIIb and/or FGFR2IIIc overexpression was significantly correlated with lymph node metastasis and clinical stage. Both FGFR2IIIb and FGFR2IIIc were significantly associated with poor overall survival. A multivariate analysis showed that FGFR2IIIc expression was significantly correlated with overall survival. FISH analysis indicated that FGFR2 amplification was correlated with FGFR2IIIb and/or FGFR2IIIc overexpression. These findings suggested that gastric tumor overexpressed FGFR2IIIc and/or FGFR2IIIb at the frequency of 4.9%. FGFR2IIIc overexpression might be independent prognostic factor for patients with gastric cancer.

CircHIPK3 Promotes the Tumorigenesis and Development of Gastric Cancer Through miR-637/AKT1 Pathway

Circular RNA is a kind of RNA with a covalently closed loop, which has a complex ability to modulate genes in the process of tumorigenesis and metastasis. Nevertheless, how circular RNA functions in gastric cancer (GC) remains unclear. The effect of circHIPK3 in vitro was studied here. Quantitative real-time PCR (qRT-PCR) was employed to found that circHIPK3 markedly increased in GC tissues and cell lines. And low expression of circHIPK3 suppressed the GC cells growing and metabolizing. Then the bioinformatics tool predicted the downstream target of circHIPK3, and it was proved by the dual-luciferase report experiment. According to the results of bioinformatics analysis and experimental data, it was clarified that circHIPK3 acted as a sponge of miR-637, releasing its direct target AKT1. The dual-luciferase assay revealed that mir-637 could bind circHIPK3 and AKT1. qRT-PCR data indicated that overexpression circHIPK3 led to the low level of miR-637 and overexpressed miR-637 would reduce AKT1 level. Finally, we demonstrated that the low expression of miR-637 or overexpression of AKT1 could attenuate the anti-proliferative effects of si-circHIPK3. These results suggest that the circHIPK3/miR-637/AKT1 regulatory pathway may be associated with the oncogene and growth of gastric cancer. In short, a new circular RNA circHIPK3 and its function are identified, and the regulatory pathway of circHIPK3/miR-637/AKT1 in the tumorigenesis and development of gastric cancer is discovered.

Enteral Vitamin B12 Supplementation Is Effective for Improving Anemia in Patients Who Underwent Total Gastrectomy

BACKGROUND

This study aimed to investigate the efficacy of enteral supplementation of vitamin B12 for vitamin B12 deficiency in patients who underwent total gastrectomy for gastric cancer.

METHODS

The study enrolled 133 patients who underwent total gastrectomy for gastric cancer at Kochi Medical School. Clinical data were obtained to investigate associations between vitamin B12 supplementation and vitamin B12 levels. Vitamin B12 deficiency was defined as serum vitamin B12 less than 200 pg/mL. Baseline characteristics and changes in hematological variables, including vitamin B12 levels, were examined.

RESULTS

Vitamin B12 deficiency was present in 71.4% of the 133 patients. Vitamin B12 levels at 3, 6, and 12 months after enteral supplementation were 306 pg/mL, 294 pg/mL, and 367 pg/mL, respectively, which were all significantly higher than those before supplementation (p < 0.001 for all comparisons). The median red blood cell count at 3, 6, and 12 months after enteral supplementation were 380 × 104/mm3, 394 × 104/mm3, and 395 × 104/mm3, respectively, which were all significantly higher than those before supplementation (p = 0.020, p = 0.001, and p = 0.003, respectively). Vitamin B12 levels at 3, 6, and 12 months after supplementation were significantly higher in patients supplemented enterally than those supplemented parenterally (p < 0.001 for all comparisons).

CONCLUSIONS

Vitamin B12 deficiency was found in 71.4% of postoperative patients who underwent total gastrectomy for gastric cancer, and enteral vitamin B12 supplements might be effective to improve anemia in these patients.

Development and validation of RNA binding protein-applied prediction model for gastric cancer

RNA-binding proteins (RBPs) have been reported to be associated with the occurrence and progression of multiple cancers, but the role in gastric adenocarcinoma remains poorly understood. The present study aims to uncover potential RBPs associated with the survival of gastric adenocarcinoma, as well as corresponding biologic properties and signaling pathways of these RBPs. RNA sequencing and clinical data of GC were obtained from The Cancer Genome Atlas (n=373) and the Gene Expression Omnibus (GSE84437, n=433) database. Tumor samples in TCGA were randomly divided into the training and internal testing group by R software. A total of 238 DERBPs were selected for univariate and multivariate Cox regression analyses. Five pivotal RBP genes (RNASE2, METTL1, ANG, YBX2 and LARP6) were screened out and were used to construct a new prognostic model. Survival relevance and prediction accuracy of model were tested via Kaplan-Meier (K-M) curves and receiver operating characteristic (ROC) curves in internal and external testing groups. Further analysis has also showed that this model could serve as an independent prognosis-related parameter. A prognostic nomogram has been eventually developed, and presents a good performance of prediction.

Molecular Mechanism of Resistance to Chemotherapy in Gastric Cancers, the Role of Autophagy

Gastric cancer (GC) is biologically and genetically heterogeneous with complex carcinogenesis at the molecular level. Despite the application of multiple approaches in the GC treatment, its 5-year survival is poor. A major limitation of anti-cancer drugs application is intrinsic or acquired resistance, especially to chemotherapeutical agents. It is known that the effectiveness of chemotherapy remains debatable and varies according to the molecular type of GC. Chemotherapy has an established role in the management of GC. Perioperative chemotherapy or postoperative chemotherapy is applied for localized ones. Most of the advanced GC patients have a poor response to treatment and unfavorable outcomes with standard therapies. Resistance substantially limits the depth and duration of clinical responses to targeted anticancer therapies. Through the use of complementary experimental approaches, investigators have revealed that cancer cells can achieve resistance through adaptation or selection driven by specific genetic, epigenetic, or microenvironmental alterations. Ultimately, these diverse alterations often lead to the activation of MAPK, AKT/mTOR, and Wnt/β-catenin signaling pathways that, when co-opted, enable cancer cells to survive drug treatments. We have summarized the mechanisms of resistance development to cisplatin, 5-fluorouracil, and multidrug resistance in the GC management. The complexity of molecular targets and components of signaling cascades altered in the resistance development results in the absence of significant benefits in GC treatment, and its efficacy remains low. The universal process responsible for the failure in the multimodal approach in GC treatment is autophagy. Its dual role in oncogenesis is the most unexplored issue. We have discussed the possible mechanism of autophagy regulation upon the action of endogenous factors and drugs. The experimental data obtained in the cultured GC cells need further verification. To overcome the cancer resistance and to prevent autophagy as the main reason of ineffective treatment, it is suggested the concept of the direct influence of autophagy molecular markers followed by the standard chemotherapy. Dozen of studies have focused on finding the rationale for the benefits of such complex therapy. The perspectives in the molecular-based management of GC are associated with the development of molecular markers predicting the protective autophagy initiation and search for novel targets of effective anticancer therapy.

Upregulation of LAMB1 via ERK/c-Jun Axis Promotes Gastric Cancer Growth and Motility

Gastric cancer is the fifth most common cancer worldwide with a poor survival rate. Therefore, it is important to identify predictive and prognostic biomarkers of gastric cancer. Laminin subunit beta 1 (LAMB1) is involved in attachment, migration, and organization during development, and its elevated expression has been associated with several cancers. However, the role and mechanism of LAMB1 in gastric cancer remains unknown. Here, we determined that LAMB1 is upregulated in gastric cancer tissues and contributes to cell growth and motility. Using a public database, we showed that LAMB1 expression was significantly upregulated in gastric cancer compared to normal tissues. LAMB1 was also found to be associated with poor prognosis in patients with gastric cancer. Overexpression of LAMB1 elevated cell proliferation, invasion, and migration; however, knockdown of LAMB1 decreased these effects in gastric cancer cells. U0126, an extracellular signal-regulated kinase (ERK) inhibitor, regulated the expression of LAMB1 in gastric cancer cells. Additionally, we showed that c-Jun directly binds to the LAMB1 promoter as a transcription factor and regulates its gene expression via the ERK pathway in gastric cancer cells. Therefore, our study indicates that LAMB1 promotes cell growth and motility via the ERK/c-Jun axis and is a potential biomarker and therapeutic target of gastric cancer.

CA724 predicts overall survival in locally advanced gastric cancer patients with neoadjuvant chemotherapy

Background

Serum tumor markers including AFU, AFP, CEA, CA199, CA125 and CA724, are of great importance in the diagnosis, prognostic prediction and recurrence monitoring of gastrointestinal malignancies. However, their significance in gastric cancer (GC) patients with neoadjuvant therapy (NCT) is still uncertain. The aim of this study was to evaluate the predictive value of these six tumor markers in locally advanced GC patients who underwent NCT and curative surgery.

Methods

In total, 290 locally advanced GC patients who underwent NCT and D2 radical gastrectomy were retrospectively analyzed. Data on their tumor markers before (pre-) and after (post-) NCT and pathological characteristics were extracted from the database of our hospital. The optimal cutoff values of the six tumor markers were calculated by the ROC curve and Youden index. Their predictive significance was analyzed and survival curves for overall survival (OS) were obtained by the Kaplan-Meier method. Associations between categorical variables were explored by the chi-square test or Fisher’s exact test. Multivariate analyses were performed by the Cox regression model.

Results

Pre- and post-CA199, −CA125 and -CA724 could predict overall survival (all P < 0.05), but only the change (diff-) of CA199 was related to prognosis (P = 0.05). In the multivariable analysis, pre- (P = 0.014) and post-CA724 (P = 0.036) remained significant, though diff-CA724 was not an independent prognostic factor (P = 0.581). In addition, pre- and post-CA199, −CA125 and -CA724 were associated with lymph node metastasis (N- vs N+) and pathological stage (I-II vs III) (all P < 0.05). Moreover, post-CA724 was related to the vascular or lymphatic invasion (P = 0.019), while pre-CA724 was not (P = 0.082). However, AFU, AFP and CEA showed no association with survival (P > 0.05).

Conclusions

CA724 is an independent factor for prognosis and could be used to predict ypN and ypTNM stage in locally advanced GC patients undergoing NCT and curative resection.

Artificial intelligence technologies empowering identification of novel diagnostic molecular markers in gastric cancer

In recent clinical practice the molecular diagnostics have been significantly empowered and upgraded by the use of Artificial Intelligence and its assisted technologies. The use of Machine leaning and Deep Learning Neural network architectures have brought in a new dimension in clinical oncological research and development. These algorithm based software system with enhanced digital image analysis have emerged into a new branch of digital pathology and contributed immensely towards precision medicine and personal diagnostics. In India, gastric cancer is one of the most common cancers in males as well as in females. Various molecular biomarkers are associated with gastric cancer development and progression of which HER2 protein, a transmembrane tyrosine kinase (TK) receptor of epidermal growth factor receptors (EGFRs) family is of prime importance. The EGF receptor expression in gastric cancer is linked with its prognostics and theragnostics. These expressions are assessed by immunohistochemistry (IHC) and molecular techniques such as Fluorescence in-situ hybridization (FISH), as per recommendations for HER2 targeted immunotherapy. These have motivated the software giants like Google Inc. to produce innovative state of art technologies mimicking human traits such as learning and problem solving skill sets. This field is still under development and is slowly evolving and capturing global importance in recent times. A literature search on PubMed was performed to access updated information for this manuscript.

Identification of functional methylated CpG loci in PD-L1 promoter as the novel epigenetic biomarkers for primary gastric cancer

Gastric cancer (GC) is considered one of the most lethal malignancies worldwide due to poor prognosis. Aberrant methylation has been demonstrated to be involved in PD-L1 dysregulated expression in human cancers and possesses a great value as a diagnostic biomarker. Given that, in this study, we investigated the methylation status of PD-L1 as a promising biomarker in primary gastric tumors and identified functional CpG loci undergoing aberrant methylation through tumorigenesis of GC. PD-L1 methylation was initially evaluated in-silico using TCGA-STAD dataset. Pearson's correlation analysis was further employed to identify the most significant functional methylated CpG loci of PD-L1 gene in TCGA-STAD patient cohort. Methylation status and its correlation with PD-L1 expression were also validated using q-MSP and qRT-PCR in a set of internal samples, including 25 paired primary gastric tumors and adjacent normal tissues. The obtained results from TCGA-STAD showed that PD-L1 is significantly hypermethylated through gastric tumorigenesis, mostly in two CpG loci overlapping with cg19724470 and cg15837913 probes. Besides, PD-L1 DNA methylation was negatively correlated with PD-L1 expression in tumor samples. Furthermore, hypermethylation of cg19724470 and cg15837913 regions was validated in primary gastric tumors compared to adjacent normal samples. Also, ROC curve analysis illustrated the high diagnostic value of PD-L1 methylation for early detection of GC (AUC = 0.8110). In conclusion, the findings of this study suggested that PD-L1 expression is regulated by methylation in functional CpG loci and its methylation could be considered as a valuable diagnostic target for GC.

Engulfment and cell motility 1 promotes tumor progression via the modulation of tumor cell survival in gastric cancer

BACKGROUND/AIM

Engulfment and cell motility 1 (ELMO1) protein has been implicated in phagocytosis of apoptotic cells, cell migration, neurite outgrowth, cancer cell invasion and metastasis, and poor prognosis in various cancers. We investigated the role of ELMO1 in mediating the oncogenic behavior of gastric cancer (GC) cells. We also investigated the correlation between expression of ELMO1 in GC tissues and various clinicopathological parameters.

METHODS

We studied the impact of ELMO1 on tumor cell behavior using the pcDNA-myc vector and small interfering RNA in AGS and SNU1750 GC cell lines. We performed western blotting and immunohistochemistry to investigate the expression of ELMO1 in GC cells and tissues.

RESULTS

ELMO1 overexpression inhibited apoptosis via the modulation of PARP, caspase-3 and caspase-7 in GC cells. ELMO1 overexpression led to significant increase in the number of migrating and invading GC cells. The expression of E-cadherin decreased and that of Snail increased in GC cells upon ELMO1 overexpression. Phosphorylation of PI3K/Akt and GSK-3β was increased and that of β-catenin was decreased upon ELMO1 overexpression in GC cells. These results were reversed after ELMO1 knockdown. ELMO1 expression was significantly associated with tumor size, cancer stage, lymph node metastasis and survival. ELMO1-positive tumors had significantly higher mean of Ki-67 labeling index than ELMO1-negative tumors. There was no significant relationship between ELMO1 expression and the mean value of the apoptotic index.

CONCLUSIONS

Our results indicate that ELMO1 promotes tumor progression by modulating tumor cell survival in human GC.

Long Noncoding RNA SNHG22 Induces Cell Migration, Invasion, and Angiogenesis of Gastric Cancer Cells via microRNA-361-3p/HMGA1/Wnt/β-Catenin Axis

Background

The correlation between long non-coding RNAs (lncRNAs) and gastric cancer (GC) has been indicated. As a newly found lncRNA, small nucleolar RNA host gene 22 (SNHG22) functions as an oncogene in ovarian carcinoma and breast cancer. However, its action has not been explored in GC. Herein, the purpose of the current research was to examine the influence of SNHG22 on GC development.

Methods

RT-qPCR was used to identify SNHG22 and microRNA-361-3p (miR-361-3p) in GC tissues and cells. Functional assays were implemented to measure changes on biological activities of GC cells under different transfections. Besides, after human umbilical vein endothelial cells (HUVECs) were co-cultured with supernatant of transfected GC cells, angiogenesis was assessed by tube formation assay in vitro. HMGA1 and β-catenin expression were determined. Finally, mechanistic assays, including RNA pull-down assay and dual-luciferase reporter assay, were employed to assess relationships among SNHG22, miR-361-3p, and HMGA1.

Results

SNHG22 and HMGA1 were highly expressed but miR-361-3p was poorly expressed in GC tissues. Mechanistically, SNHG22 bound to miR-361-3p, and miR-361-3p targeted HMGA1 to disrupt the Wnt/β-catenin pathway. Following SNHG22 or HMGA1 silencing or miR-361-3p upregulation, we observed a decline of proliferation, migration, and invasion of GC cells and HUVEC angiogenesis but acceleration of GC cell apoptosis and cell cycle arrest.

Conclusion

Collectively, SNHG22 silencing possessed tumor-suppressing potentials in GC development via Wnt/β-catenin pathway by binding to miR-361-3p and downregulating HMGA1, highlighting a new promising road for GC treatment development.

Multicohort Retrospective Validation of a Predictive Biomarker for Topoisomerase I Inhibitors

PURPOSE

The camptothecin (CPT) analogs topotecan and irinotecan specifically target topoisomerase I (topoI) and are used to treat colorectal, gastric, and pancreatic cancer. Response rate for this class of drug varies from 10% to 30%, and there is no predictive biomarker for patient stratification by response. On the basis of our understanding of CPT drug resistance mechanisms, we developed an immunohistochemistry-based predictive test, P-topoI-Dx, to stratify the patient population into those who did and did not experience a response.

PATIENTS AND METHODS

The retrospective validation studies included a training set (n = 79) and a validation cohort (n = 27) of gastric cancer (GC) patients, and 8 cohorts of colorectal cancer (CRC) patient tissue (n = 176). Progression-free survival for 6 months was considered a positive response to CPT-based therapy. Formalin-fixed, paraffin-embedded slides were immunohistochemically stained with anti-phospho-specific topoI-Serine10 (topoI-pS10), quantitated, and analyzed statistically.

RESULTS

We determined a threshold of 35% positive staining to offer optimal test characteristics in GC. The GC (n = 79) training set demonstrated 76.6% (95% confidence interval, 64-86) sensitivity; 68.8% (41-88) specificity; positive predictive value (PPV) 92.5% (81-98); and negative predictive value (NPV) 42.3% (24-62). The GC validation set (n = 27) demonstrated 82.4% (56-95) sensitivity and 70.0% (35-92) specificity. Estimated PPV and NPV were 82.4% (56-95) and 70.0% (35-92) respectively. In the CRC validation set (n = 176), the 40% threshold demonstrated 87.5% (78-94) sensitivity; 70.0% (59-79) specificity; PPV 70.7% (61-79); and NPV 87.0 % (77-93).

CONCLUSION

The analysis of retrospective data from patients (n = 282) provides clinical validity to our P-topoI-Dx immunohistochemical test to identify patients with disease that is most likely to respond to topoI inhibitors.

Selective expression of KCNA5 and KCNB1 genes in gastric and colorectal carcinoma

Background

Gastric and colorectal cancers are the most common malignant tumours, leading to a significant number of cancer-related deaths worldwide. Recently, increasing evidence has demonstrated that cancer cells exhibit a differential expression of potassium channels and this can contribute to cancer progression. However, their expression and localisation at the somatic level remains uncertain. In this study, we have investigated the expression levels of KCNB1 and KCNA5 genes encoding ubiquitous Kv2.1 and Kv1.5 potassium channels in gastric and colorectal tumours.

Methods

Gastric and colorectal tumoral and peritumoral tissues were collected to evaluate the expression of KCNB1 and KCNA5 mRNA by quantitative PCR. Moreover, the immunohistochemical staining profile of Kv2.1 and Kv1.5 was assessed on 40 Formalin-Fixed and Paraffin-Embedded (FFPE) gastric carcinoma tissues. Differences in gene expression between tumoral and peritumoral tissues were compared statistically with the Mann-Whitney U test. The association between the clinicopathological features of the GC patients and the expression of both Kv proteins was investigated with χ2 and Fisher’s exact tests.

Results

The mRNA fold expression of KCNB1 and KCNA5 genes showed a lower mean in the tumoral tissues (0.06 ± 0.17, 0.006 ± 0.009) compared to peritumoral tissues (0.08 ± 0.16, 0.16 ± 0.48, respectively) without reaching the significance rate (p = 0.861, p = 0.152, respectively). Interestingly, Kv2.1 and Kv1.5 immunostaining was detectable and characterised by a large distribution in peritumoral and tumoral epithelial cells. More interestingly, inflammatory cells were also stained. Surprisingly, Kv2.1 and Kv1.5 staining was undoubtedly and predominantly detected in the cytoplasm compartment of tumour cells. Indeed, the expression of Kv2.1 in tumour cells revealed a significant association with the early gastric cancer clinical stage (p = 0.026).

Conclusion

The data highlight, for the first time, the potential role of Kv1.5 and Kv2.1 in gastrointestinal-related cancers and suggests they may be promising prognostic markers for these tumours.

Serpin peptidase inhibitor clade A member 1-overexpression in gastric cancer promotes tumor progression in vitro and is associated with poor prognosis

Gastric cancer is the second most common cause of cancer-associated death in Asia. The incidence and mortality rates of gastric cancer have markedly increased in the past few decades. Therefore, the identification of novel gastric cancer biomarkers are needed to determine prognosis. The role of serpin peptidase inhibitor clade A member 1 (SERPINA1) has been studied in several types of cancer; however, little is known about its mechanism in gastric cancer. The present study aimed to evaluate SERPINA1 as a potential prognostic biomarker in gastric cancer and to identify the possible mechanisms underlying its action. The expression levels of SERPINA1 in several gastric cancer datasets were assessed, and it was identified that high expression of SERPINA1 was associated to poor clinical outcomes. Furthermore, using histochemical analysis, western blotting, apoptotic analysis, gap closure and invasion assays in cell lines, it was reported that silencing of SERPINA1 inhibited the formation of cellular pseudopodia and did not affect apoptosis, but promoted cell cycle S-phase entry. In addition, overexpression of SERPINA1 increased the migration and invasion of gastric cancer cells, whereas knockdown of SERPINA1 decreased these functions. Moreover, SERPINA1 overexpression increased the protein levels of SMAD4, which is a key regulator of the transforming growth factor (TGF)-β signaling pathway. Taken together, the present data demonstrated that SERPINA1 promotes gastric cancer progression through TGF-β signaling, and suggested that SERPINA1 may be a novel prognostic biomarker from tumor tissue biopsy in gastric cancer.

In vitro anticancer activity of Eclipta alba whole plant extract on colon cancer cell HCT-116

BACKGROUNDS

Colon cancer is the third most deadly and one of the most diagnosed diseases in the world. Although routine screening and early detection during last decades has improved the survival, colon cancer still claims hundreds of thousands lives each year worldwide. Surgery and chemotherapy is mainstay of current treatment, nevertheless toxicity associated with this treatment underscores the urgency of demand of a better therapeutics. Close to 50% of current chemotherapeutic drugs are direct or indirect descendants compounds isolated from medicinal plants, which indicate plants are great potential sources of novel therapeutics. In our literature review we found Eclipta alba to posses many pharmacological activities, including those with anticancer potentials. However, no study on anticancer activity of this kind has been reported.

METHODS

Phytochemicals were extracted by maceration method from shade dried whole plant of Eclipta alba using methanol as a solvent. The anticancer effect of extract was investigated on various cancer cell lines like human colorectal carcinoma (HCT-116), human prostate cancer (PC-3), Michigan cancer foundation-breast cancer (MCF-7) and renal cell carcinoma (RCC-45). We have also studied the effects on normal human embryonic lung fibroblast cell (WI-38) using MTT (methyl thiazoldiphenyltetrazolium bromide) assay, clonogenic (colony formation) and migration assay. Finally obtained results were analyzed using ANNOVA and Dunnett's test.

RESULTS

Results obtained from MTT assay revealed that the methanolic extract of Eclipta alba carried significant (p < 0.005) specificity against HCT-116 cells as compared to the other cancer cells. This extract also showed minimal or nontoxicity to WI-38 cells. Migration as well as clonogenic assays also confirmed the anticancer potential of the extract against HCT-116 cells.

CONCLUSION

This is a unique finding of its kind because the specific anticancer effect with minimal toxicity on normal cells has not been reported on Eclipta alba extract. Finally this finding opens up a great possibility to develop a novel antitumor drug candidate against deadly colon cancer in the future.

Electrochemical Biosensors for Detection of MicroRNA as a Cancer Biomarker: Pros and Cons

Cancer is the second most fatal disease in the world and an early diagnosis is important for a successful treatment. Thus, it is necessary to develop fast, sensitive, simple, and inexpensive analytical tools for cancer biomarker detection. MicroRNA (miRNA) is an RNA cancer biomarker where the expression level in body fluid is strongly correlated to cancer. Various biosensors involving the detection of miRNA for cancer diagnosis were developed. The present review offers a comprehensive overview of the recent developments in electrochemical biosensor for miRNA cancer marker detection from 2015 to 2020. The review focuses on the approaches to direct miRNA detection based on the electrochemical signal. It includes a RedOx-labeled probe with different designs, RedOx DNA-intercalating agents, various kinds of RedOx catalysts used to produce a signal response, and finally a free RedOx indicator. Furthermore, the advantages and drawbacks of these approaches are highlighted.

Development and Validation of a Scoring System Based on 9 Glycolysis-Related Genes for Prognosis Prediction in Gastric Cancer

Gastric cancer is a malignant tumor with high morbidity and mortality worldwide. However, increasing evidences have revealed the correlation between the glycolysis process and tumorigenesis. This study is aim to develop a list of glycolysis-related genes for risk stratification in gastric cancer patients. We included 500 patients’ sample data from GSE62254 and GSE26942 datasets, and classified patients into training (n = 350) and testing sets (n = 150) at a ratio of 7: 3. Univariate and multivariate Cox regression analysis were performed to screen genes having prognostic value. Based on HALLMARK gene sets, we identified 9 glycolysis-related genes (BPNT1, DCN, FUT8, GMPPA, GPC3, LDHC, ME2, PLOD2, and UGP2). On the basis of risk score developed by the 9 genes, patients were classified into high- and low-risk groups. The survival analysis showed that the high-risk patients had a worse prognosis (p < 0.001). Similar finding was observed in the testing cohort and 2 independent cohorts (GSE13861 and TCGA-STAD, all p < 0.001). The multivariate Cox regression analysis showed that the risk score was an independent prognostic factor for overall survival (p < 0.001). Furthermore, we constructed a nomogram that integrated the risk score and tumor stage, age, and adjuvant chemotherapy. Through comparing the results of the receiver operating characteristic curves and decision curve analysis, we found that the nomogram had a superior predictive accuracy than conventional TNM staging system, suggesting that the risk score combined with other clinical factors (age, tumor stage, and adjuvant chemotherapy) can develop a robust prediction for survival and improve the individualized clinical decision making of the patient.

In conclusion, we identified 9 glycolysis-related genes from hallmark glycolysis pathway. Based on the 9 genes, gastric cancer patients were separated into different risk groups related to survival.

Signature based on molecular subtypes of deoxyribonucleic acid methylation predicts overall survival in gastric cancer

BACKGROUND

Gastric cancer (GC) ranks as the third leading cause of cancer-related death worldwide. Epigenetic alterations contribute to tumor heterogeneity in early stages.

AIM

To identify the specific deoxyribonucleic acid (DNA) methylation sites that influence the prognosis of GC patients and explore the prognostic value of a model based on subtypes of DNA methylation.

METHODS

Patients were randomly classified into training and test sets. Prognostic DNA methylation sites were identified by integrating DNA methylation profiles and clinical data from The Cancer Genome Atlas GC cohort. In the training set, unsupervised consensus clustering was performed to identify distinct subgroups based on methylation status. A risk score model was built based on Kaplan-Meier, least absolute shrinkage and selector operation, and multivariate Cox regression analyses. A test set was used to validate this model.

RESULTS

Three subgroups based on DNA methylation profiles in the training set were identified using 1061 methylation sites that were significantly associated with survival. These methylation subtypes reflected differences in T, N, and M category, age, stage, and prognosis. Forty-one methylation sites were screened as specific hyper- or hypomethylation sites for each specific subgroup. Enrichment analysis revealed that they were mainly involved in pathways related to carcinogenesis, tumor growth, and progression. Finally, two methylation sites were chosen to generate a prognostic model. The high-risk group showed a markedly poor prognosis compared to the low-risk group in both the training [hazard ratio (HR) = 2.24, 95% confidence interval (CI): 1.28-3.92, P < 0.001] and test (HR = 2.12, 95%CI: 1.19-3.78, P = 0.002) datasets.

CONCLUSION

DNA methylation-based classification reflects the epigenetic heterogeneity of GC and may contribute to predicting prognosis and offer novel insights for individualized treatment of patients with GC.

Incidence and risk factors of osteoporotic status in outpatients who underwent gastrectomy for gastric cancer

Background and Aim

Disorders in bone metabolism have long been recognized as typical sequelae of gastrectomy; however, the pathogenesis has not been fully elucidated, resulting in a variation of reported incidence. This study aimed to evaluate current bone health by measuring bone mineral density (BMD) in patients treated by gastrectomy for gastric cancer, with a focus on incidence and risk factors of osteoporosis.

Methods

The study enrolled 81 patients who underwent gastrectomy for gastric cancer at Kochi Medical School. BMD of the lumbar spine was measured by dual‐energy X‐ray mineral absorptiometry, with the results expressed as a percentage of the young adult mean (YAM). Clinical data were also obtained to investigate associations with BMD.

Results

Of the 81 study patients, 12 (14.8%) were deemed to have osteoporosis, defined by a percentage of YAM <70, with a dominance of females over males (66.7% vs 17.4%; P < 0.001). The median body weight, hemoglobin concentration, and serum alkaline phosphatase (ALP) level of the patients with osteoporosis was significantly lower than in those with a percentage of YAM ≥70 group (39.6 kg vs 53.1 kg, P < 0.001; 10.9 mg/dL vs 12.5 mg/dL, P = 0.010; 210 U/L vs 251 U/L, P = 0.002). Further analyses revealed a significant positive correlation between body weight and percentage of YAM (r = 0.441, P < 0.001). Despite the administration of bisphosphonates in these patients during this study, one acquired a bone fracture.

Conclusion

Osteoporosis was found in 14.8% of postoperative gastric cancer patients, with female gender, low body weight, and low ALP proposed as risk factors for osteoporosis and thus future bone fracture.

Development and validation of metabolism-related gene signature in prognostic prediction of gastric cancer

Gastric cancer is one of the most common malignant tumours in the world. As one of the crucial hallmarks of cancer reprogramming of metabolism and the relevant researches have a promising application in the diagnosis treatment and prognostic prediction of malignant tumours. This study aims to identify a group of metabolism-related genes to construct a prediction model for the prognosis of gastric cancer.

A large cohort of gastric cancer cases (1121 cases) from public database was included in our analysis and classified patients into training and testing cohorts at a ratio of 7: 3. After identifying a list of metabolism-related genes having prognostic value, we constructed a risk score based on metabolism-related genes using LASSO-COX method. According to the risk score, patients were divided into high- and low-risk groups. Our results revealed that high-risk patients had a significantly worse prognosis than low-risk patients in both the training (high-risk vs low-risk patients; five years overall survival: 37.2% vs 72.2%; p < 0.001) and testing cohorts (high-risk vs low-risk patients; five years overall survival: 42.9% vs 62.9%; p < 0.001). This observation was validated in the external validation cohort (high-risk vs. low-risk patients; five years overall survival: 30.2% vs 40.4%; p = 0.007).

To reinforce the predictive ability of the model, we integrated risk score, age, adjuvant chemotherapy, and TNM stage into a nomogram. According to the result of receiver operating characteristic curves and decision curves analysis, we found that the nomogram score had a superior predictive ability than conventional factors, indicating that the risk score combined with clinicopathological features can develop a robust prediction for survival and improve the individualized clinical decision making of the patient.

In conclusion, we identified a list of metabolic genes related to survival and developed a metabolism-based predictive model for gastric cancer. Through a series of bioinformatics and statistical analyses, the predictive ability of the model was confirmed.

Probiotic Lactobacillus rhamnosus Supplementation Improved Capecitabine Protective Effect against Gastric Cancer Growth in Male BALB/c Mice

The gastric cancer (GC) is biologically and genetically heterogeneous with a poorly understood carcinogenesis at the molecular level. Herein, we studied the effects of probiotics (Lactobacillus rhamnosus) on subcutaneous implantation of xenograft GC. Moreover, the effect of probiotics (L. rhamnosus) was compared with the capecitabine drug as known used drug against GC. Human GC tissue was obtained from patients with gastric adenocarcinoma and grafted into mice armpit. Probiotic (L. rhamnosus) was given to animals by gavage 2 weeks prior to GC and 4 weeks after GC induction. Also, capecitabine was orally added through feeding tube at the last week of treatment procedure. All grafted animals received cyclosporine a day before the surgery and during the study period to prevent graft rejection. Capecitabine-probiotic complex reduced the size of the axillary implanted GC when compared with control group. Furthermore, combination of capecitabine and probiotic increased apoptotic and necrotic responses in the grafted tumor, blood cells (red blood cells, white blood cells, and platelet counts) in comparison with capecitabine. Probiotic (L. rhamnosus) administration effectively improved the therapeutic index and outcomes, and also, improved the therapeutic effects of the capecitabine.

Non-Invasive Early Molecular Detection of Gastric Cancers

Gastric cancer (GC) is a significant source of global cancer death with a high mortality rate, because the majority of patients with GC are diagnosed at a late stage, with limited therapeutic choices and poor outcomes. Therefore, development of minimally invasive or noninvasive biomarkers which are specific to GC is crucially needed. The latest advancements in the understanding of GC molecular landscapes and molecular biological methods have accelerated attempts to diagnose GC at an early stage. Body fluids, including peripheral blood, saliva, gastric juice/wash, urine, and others, can be a source of biomarkers, offering new methods for the early detection of GC. Liquid biopsy-based methods using circulating sources of cancer nucleic acids could also be considered as alternative strategies. Moreover, investigating gastric juices/washes could represent an alternative for the detection of GC via invasive biopsy. This review summarizes recently reported biomarkers based on DNA methylation, microRNA, long noncoding RNA, circular RNA, or extracellular vesicles (exosomes) for the detection of GC. Although the majority of studies have been conducted to detect these alterations in advanced-stage GC and only a few in population studies or early-stage GC, some biomarkers are potentially valuable for the development of novel approaches for an early noninvasive detection of GC.

Circulating Irisin Levels and Redox Status Markers in Patients with Gastric Cancer: A Case-Control Study

Objective:

Irisin, mostly known as an exercise-induced fat browning myokine, has been recently detected in several cancer cells, and its potential for being utilized as a biomarker for early diagnosis of some cancers, such as Gastric cancer (GC), is the subject of speculation. The present study aims to compare serum irisin levels in GC patients and healthy controls and assess the interrelation between irisin and oxidative stress markers.

Methods:

In this case-control study, 22 newly diagnosed GC patients and 29 healthy controls were recruited based on the inclusion criteria. Serum levels of irisin were quantified in duplicates by ELISA. Oxidative stress indices, including total antioxidant power in sera, thiol group, malondialdehyde, and superoxide dismutase concentrations, were also measured in both groups. An independent-sample t-test was used to compare the means between the two studied groups.

Results:

Serum levels of irisin were significantly higher in the GC group compared with those of their healthy counterparts (p =0.032). No significant differences were observed between the two groups in terms of the serum total antioxidant power or the oxidative stress marker, including MDA, thiol groups, and SOD concentration in sera. Furthermore, there was no significant association between irisin, FRAP, the Thiol group, and the SOD activity.

Conclusion:

According to the finding, the increased serum levels of irisin in GC patients can play a potential role in the early diagnosis of the GC patients; hence, this peptide can be employed as a new diagnostic indicator of GC.

CRISPR/Cas: From Tumor Gene Editing to T Cell-Based Immunotherapy of Cancer

The clustered regularly interspaced short palindromic repeats system has demonstrated considerable advantages over other nuclease-based genome editing tools due to its high accuracy, efficiency, and strong specificity. Given that cancer is caused by an excessive accumulation of mutations that lead to the activation of oncogenes and inactivation of tumor suppressor genes, the CRISPR/Cas9 system is a therapy of choice for tumor genome editing and treatment. In defining its superior use, we have reviewed the novel applications of the CRISPR genome editing tool in discovering, sorting, and prioritizing targets for subsequent interventions, and passing different hurdles of cancer treatment such as epigenetic alterations and drug resistance. Moreover, we have reviewed the breakthroughs precipitated by the CRISPR system in the field of cancer immunotherapy, such as identification of immune system-tumor interplay, production of universal Chimeric Antigen Receptor T cells, inhibition of immune checkpoint inhibitors, and Oncolytic Virotherapy. The existing challenges and limitations, as well as the prospects of CRISPR based systems, are also discussed.

Prognostic Value of C-Reactive Protein to Albumin Ratio in Gastric Cancer: A Meta-Analysis

OBJECTIVE

C-reactive protein to albumin ratio (CRP/Alb) is investigated as a prognostic marker in gastric cancer in previous studies, with presence of inconsistent data. Therefore, this study aimed to explore the prognostic role of CRP/Alb in gastric cancer through meta-analysis.

METHODS

This meta-analysis systemically retrieved PubMed, Embase, Web of Science, the Chinese National Knowledge Infrastructure (CNKI), and Wanfang up to July 4, 2020. Pooled hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) were conducted to evaluate the association between CRP/Alb and survival outcomes.

RESULTS

A total of nine studies with 3346 patients were included in the present meta-analysis. The pooled HR and 95%CI were: HR = 1.89, 95%CI = 1.64-2.19, p < 0.001 for overall survival (OS) and HR = 2.15, 95%CI = 1.72-2.70, p < 0.001 for disease-free survival (DFS). Subgroup analysis demonstrate that an elevated CRP/Alb remain a significant prognostic factor for poor OS and DFS irrespective of sample size, nationality of patients, or cutoff value resource (p < 0.05 in all subgroups).

CONCLUSIONS

The present meta-analysis suggests that high CRP/Alb is predictive of poor OS and DFS in gastric cancer. CRP/Alb is therefore a potential prognostic factor in the management of patients with gastric cancer.

COL4A family: potential prognostic biomarkers and therapeutic targets for gastric cancer

Background

The type IV collagen alpha chain (COL4A) family is a major component of the basement membrane (BM) that has recently been found to be involved in tumor angiogenesis and progression. However, the expression levels and the exact roles of distinct COL4A family members in gastric cancer (GC) have not been completely understood.

Methods

Here, the expression levels of COL4As in GC and normal gastric tissues were calculated by using TCGA datasets and the predicted prognostic values by the GEPIA tool. Furthermore, the cBioPortal and Metascape tools were integrated to analyze the genetic alterations, correlations and potential functions of COL4As, and their frequently altered neighboring genes in GC.

Results

Notably, the expression levels of COL4A1/2/4 in GC were higher to those in normal gastric tissues, while the expression levels of COL4A3/5/6 were lower in GC than normal. Survival analysis revealed that lower expression levels of COL4A1/5 led to higher overall survival (OS) rate. Multivariate analysis using the Cox proportional-hazards model indicated that age, gender, pathological grade, metastasis and COL4A5 expression, are independent prognostic factors for OS. However, TNM stage, lymph node metastasis, Lauren’s classification, COL4A1-4 and COL4A6 were associated with poor OS but not independent prognostic factors. Function-enriched analysis of COL4As and their frequently altered neighboring genes was involved in tumor proliferation and metastasis in GC.

Conclusions

These results implied that COL4A1/2 were potential therapeutic targets for GC. COL4A3/4/6 might have an impact on gastric carcinogenesis and subsequent progression, whereas COL4A5 was an independent prognostic marker for GC.

An insight into the roles of piRNAs and PIWI proteins in the diagnosis and pathogenesis of oral, esophageal, and gastric cancer

P-Element induced wimpy testis (PIWI)-interacting RNA (piRNA) is a member of the non-coding RNAs family. Four PIWI proteins are found to be expressed in humans. The number of studies focusing on the roles of piRNAs and PIWI proteins in the field of cancer is increasing. Oral, esophageal, and gastric cancers are considered as important causes of death. PIWI proteins and piRNAs are suggested to be involved in the pathogenesis of these diseases. Thus, studying these molecules may be beneficial for finding new therapeutics. Since it is shown that currently used biomarkers for these cancers have low sensitivity and specificity, there is a necessity for identifying novel non-invasive biomarkers which are highly sensitive and specific. This paper will provide an insight into current knowledge about the functions of PIWI proteins and piRNAs in the oral, esophageal, and gastric cancer. We discuss how PIWI proteins and piRNAs can be involved in the pathogenesis of these cancers. Moreover, we review the studies concerning with the roles of PIWI proteins and piRNAs as biomarkers which are used for diagnostic and prognostic purposes.

Retrospective epidemiological study on stomach cancer in a region of western Algeria: about 394 cases between 2011 and 2015

PURPOSE

Stomach cancer is a major global health problem; it is one of the ten most common cancers with poor survival, and its incidence is characterized by wide variation. The aim of this work is to carry out a retrospective epidemiological study on gastric cancer in the wilaya of Tlemcen (West Algeria) over a period of 5 years (2011-2015).

METHODS

The data set was provided by the cancer registry of the Tlemcen wilaya. The statistical analysis was performed using software SPSS.21.

RESULTS

During this period, 394 cases of gastric cancers were collected, including 199 patients with gastric adenocarcinoma (50.50%); gastric cancer was ranked in 5th rank of the ten most answered cancers in the wilaya. The average age of the patients was 60.5 ±  14.208 years (60.618 ±  13.556 men, 56.654 ±  14.8761 women) with an extremity ranging from 18 to 91 years. A predominance of men has been observed with 60.4% against 39.6% of women, with a sex ratio of 1.5 and a significant difference between the two sexes (p = 0.08). Patients over 50 years of age represented the predominant age group (73.4%). The tumor topography was antropyloric in 6.09% of the cases, and the vast majority of the diagnosed cases was in the local stage (17.01%).

CONCLUSION

Stomach cancer remains one of the top ten cancers in the Tlemcen willaya, so extensive research on the risk factors for gastric cancer remains important to plan effective preventive and curative strategies to reduce this burden.

Identification of the collagen family as prognostic biomarkers and immune-associated targets in gastric cancer

BACKGROUND

Gastric cancer has extremely high morbidity and mortality. Currently, it is lack of effective biomarkers and therapeutic targets for guiding clinical treatment. In this study, we aimed to identify novel biomarkers and therapeutic targets for gastric cancer.

METHODS

Differentially expressed genes (DEGs) between gastric cancer and normal tissues were obtained from Gene Expression Omnibus (GEO). Core genes were identified by constructing protein-protein interaction network of DEGs. The expression of core genes was verified in Gene Expression Profiling Interactive Analysis (GEPIA), UALCAN and clinical samples. Further, the mutation, DNA methylation, prognostic value, and immune infiltration of core genes were validated by cBioPortal, MethSurv, Kaplan-Meier plotter, and Tumor Immune Estimation Resource (TIMER) databases. Additionally, drug response analysis was performed by Cancer Therapy Response Portal (CTRP).

RESULTS

A total of seven collagen family members were identified as core genes among upregulated genes. And copy number amplification may be involved in the upregulation of COL1A1 and COL1A2. Importantly, the collagen family was associated with the poor prognosis of patients with metastasis. Among them, COL1A1 had a higher hazard ratio (HR) for overall survival than other members (HR = 2.33). The correlation between DNA methylation levels at CpG sites of collagen family members and the prognosis was verified in gastric cancer. Besides, collagen family expression was positively correlated with macrophages infiltration and the expression of M2 macrophages markers. Further, collagen expression was related to the sensitivity and resistance of gastric cancer cell lines to certain drugs.

CONCLUSIONS

The collagen family, especially COL1A1, COL1A2, and COL12A1, may act as potential prognostic biomarkers and immune-associated therapeutic targets in gastric cancer.

A protocol of systematic review and meta-analysis of narrow band imaging endoscopy in detection of early gastric cancer

BACKGROUND

Although previous studies have utilized narrow band imaging endoscopy diagnosis (NBIED) in detection of patients with early gastric cancer (EGC), there are still inconsistent results. Thus, this study will explore the accuracy of NBIED in detection of patients with EGC.

METHODS

We propose to perform literature search of potential studies investigating the accuracy of NBIED in detection of patients with EGC in MEDLINE, EMBASE, Cochrane Library, Web of Science, WANGFANG, VIP database and China National Knowledge Infrastructure from the beginning of each database to January 31, 2020 without restrictions to language and publication time. Two authors will independently scrutinize these databases to identify studies that satisfy all predefined eligibility criteria. We will check study quality and analyze outcome data using Quality Assessment of Diagnostic Accuracy Studies tool, and RevMan 5.3 software respectively.

RESULTS

We anticipate the results of this study will afford additional insight into the appraising of the accuracy of NBIED in patients with EGC.

CONCLUSION

The findings of this study will be useful informing diagnostic decisions for the diagnosis of patients with EGC.PROSPERO registration number: PROSPERO CRD42020171053.

Identification of a Tumor Microenvironment-relevant Gene set-based Prognostic Signature and Related Therapy Targets in Gastric Cancer

Rationale: The prognosis of gastric cancer (GC) patients is poor, and there is limited therapeutic efficacy due to genetic heterogeneity and difficulty in early-stage screening. Here, we developed and validated an individualized gene set-based prognostic signature for gastric cancer (GPSGC) and further explored survival-related regulatory mechanisms as well as therapeutic targets in GC. Methods: By implementing machine learning, a prognostic model was established based on gastric cancer gene expression datasets from 1699 patients from five independent cohorts with reported full clinical annotations. Analysis of the tumor microenvironment, including stromal and immune subcomponents, cell types, panimmune gene sets, and immunomodulatory genes, was carried out in 834 GC patients from three independent cohorts to explore regulatory survival mechanisms and therapeutic targets related to the GPSGC. To prove the stability and reliability of the GPSGC model and therapeutic targets, multiplex fluorescent immunohistochemistry was conducted with tissue microarrays representing 186 GC patients. Based on multivariate Cox analysis, a nomogram that integrated the GPSGC and other clinical risk factors was constructed with two training cohorts and was verified by two validation cohorts. Results: Through machine learning, we obtained an optimal risk assessment model, the GPSGC, which showed higher accuracy in predicting survival than individual prognostic factors. The impact of the GPSGC score on poor survival of GC patients was probably correlated with the remodeling of stromal components in the tumor microenvironment. Specifically, TGFβ and angiogenesis-related gene sets were significantly associated with the GPSGC risk score and poor outcome. Immunomodulatory gene analysis combined with experimental verification further revealed that TGFβ1 and VEGFB may be developed as potential therapeutic targets of GC patients with poor prognosis according to the GPSGC. Furthermore, we developed a nomogram based on the GPSGC and other clinical variables to predict the 3-year and 5-year overall survival for GC patients, which showed improved prognostic accuracy than clinical characteristics only. Conclusion: As a tumor microenvironment-relevant gene set-based prognostic signature, the GPSGC model provides an effective approach to evaluate GC patient survival outcomes and may prolong overall survival by enabling the selection of individualized targeted therapy.

High plasma levels of COL10A1 are associated with advanced tumor stage in gastric cancer patients

BACKGROUND

Gastric cancer (GC) remains an aggressive malignancy with a high rate of mortality, being the third leading cause of cancer-related death. More than one million newly diagnosed cases and 782685 deaths due to GC were reported in 2018. GC is characterized by limited effective treatment options and the lack of consistent biomarkers for the diagnosis and prognosis of these patients. The discovery of new biomarkers useful in the early diagnosis of GC is mandatory.

AIM

To evaluate the potential of COL10A1 as a circulating biomarker for the diagnosis and prognosis of gastric adenocarcinoma patients.

METHODS

Plasma and tissue obtained from 49 patients with gastric adenocarcinoma have been used in exploring the expression of COL10A1. Real-time PCR and western blot techniques were used to evaluate COL10A1 level in gastric tumor tissue compared to normal adjacent tissue. The circulating level of COL10A1 was also evaluated by ELISA in plasma of gastric adenocarcinoma patients. Survival analysis was made in order to evaluate the potential of COL10A1 as a biomarker for the diagnosis and prognosis of gastric adenocarcinoma patients.

RESULTS

Our results showed a significant increase in COL10A1 gene expression and protein levels in gastric tumor tissue compared to adjacent normal tissue (P < 0.05). COL10A1 seems to show an elevated expression from the beginning of carcinogenesis, in the early stages, and its increased level remains elevated during cancer progression. A significant increase of COL10A1 plasma level in gastric adenocarcinoma patients was also identified. Moreover, increased COL10A1 plasma level was associated with poor survival of the patients. Plasma COL10A1 performed a diagnostic value in GC with area under the receiver operating characteristic curve (AUC) of 0.9171 (P = 0.0002), sensitivity of 87.76%, and specificity of 100.0%. Furthermore, this study demonstrated the potential role of plasma COL10A1 in the early detection of GC, as in the early stage, we obtained an AUC of 0.8789 (P = 0.0030), sensitivity of 81.25%, and specificity of 100.0%.

CONCLUSION

Circulating expression level of COL10A1 is significantly increased in gastric adenocarcinoma patients being associated with poor survival and is a potential biomarker for early detection of GC.

Gastric cancer risk-scoring system based on analysis of a competing endogenous RNA network

Background

Long noncoding RNAs (lncRNAs) can play vital roles in tumor initiation, progression, invasion, and metastasis. However, the functional role of the lncRNA-based competing endogenous RNA (ceRNA) networks in gastric cancer (GC) is still unclear. We aimed to identify novel lncRNAs and their association with GC prognosis.

Methods

The lncRNA, miRNA, and mRNA expression profiles of GC patients data were obtained from The Cancer Genome Atlas (TCGA) database. Differentially expressed genes (DEGs) were identified using the edge-R package. Then, the relationship among lncRNAs-miRNAs-mRNAs was integrated into a constructed ceRNA network with Cytoscape software. Using Cox regression analysis, a risk score system based on DEGs associated with patient prognosis in GC was established. Finally, a nomogram was founded to predict the prognosis of GC patients.

Results

A total of 971 differentially expressed lncRNAs (DElncRNAs), 144 differentially expressed miRNAs (DEmiRNAs) and 2,789 differentially expressed mRNAs (DEmRNAs) were identified and found to be associated with GC risk. Using the bioinformatics method, a ceRNA network involving 62 DElncRNAs, 21 DEmiRNAs and 59 DEmRNAs was constructed. Based on the results of the Cox regression analysis, a risk-scoring system involving 3 lncRNAs (i.e., ADAMTS9-AS1, C15orf54, and AL391152.1) was set up for the survival analysis of GC patients. The area under the receiver operating characteristic (ROC) curve for the risk-scoring system was 0.674, with a C-index of 0.64 [95% confidence interval (CI): 0.59–0.69, P=2.806485e−08]. Univariate and multivariate Cox regression analyses demonstrated that the risk-scoring system was an independent prognostic factor for GC. The risk-scoring system is positively associated with advanced tumor grade. The expression of these 3 lncRNAs were validated in GEPIA database. A nomogram based on these 3 lncRNAs was created to predict the prognosis of GC patients.

Conclusions

Our study established a novel lncRNA-expression-based ceRNA network and an ADAMTS9-AS1-C15orf54-AL391152.1-based risk-scoring system, which can be used to predict the prognosis of GC patients.

Immune Checkpoint Inhibitors in Locally Advanced, Unresectable, and Metastatic Upper Gastrointestinal Malignancies

BACKGROUND

Upper gastrointestinal (UGI) malignancies including esophageal, gastroesophageal junction (GEJ), and gastric cancers have a poor prognosis in the metastatic setting. Treatment with cytotoxic chemotherapy remains the treatment of choice in the first-line setting with the addition of trastuzumab, a monoclonal antibody against HER-2, if the tumor is HER2-positive. Before the era of checkpoint inhibitors, there were only few treatment options after failure of the first-line systemic therapy.

METHODS

We extensively searched the English written literature for peer-reviewed manuscripts regarding the use of checkpoint inhibitors in advanced stage and metastatic UGI cancer. We also searched and reviewed ongoing clinical trials from Clinicaltrials.gov.

RESULTS

Checkpoint inhibition is a promising therapeutic option in UGI cancers, which have overexpression of PD-L1, high mutation burden, or microsatellite instability. Checkpoint inhibitors that are being investigated or are approved in advanced UGI malignancies include PD-1 antibodies, nivolumab and pembrolizumab, PD-L1 antibody, avelumab, and CTLA-4 inhibitors, ipilimumab and tremelimumab.

CONCLUSIONS

Based on recent and ongoing studies, eligible patients who have progressed beyond the first-line cytotoxic chemotherapy may benefit from immunotherapy. This review outlines the checkpoint inhibitors that are currently or previously being investigated for patients with metastatic UGI cancers.

CD40 DNA hypermethylation in primary gastric tumors; as a novel diagnostic biomarker

AIMS

Gastric cancer (GC) remains one of the deadliest malignancies worldwide due to its poor prognosis. DNA methylation changes, as an early event during tumor progression, constitute attractive markers for cancer diagnostics. In the current study, CD40 DNA methylation was investigated in GC as a novel epigenetic biomarker.

MAIN METHODS

We first analyzed DNA methylation microarrays from the Gene Expression Omnibus database on GC samples to evaluate the potential diagnostic value of CD40 methylation. Moreover, using q-MSP, in a set of internal samples including GC primary tumors and adjacent normal specimens, CD40 DNA methylation levels were determined. The Cancer Genome Atlas (TCGA) data on GC was also analyzed for further validation.

KEY FINDINGS

Our results illustrated significant CD40 hypermethylation in GC samples compared to normal specimens which was significantly correlated with the clinical stage of malignancy. Besides, the high accuracy of CD40 methylation as a diagnostic biomarker in GC was confirmed using the ROC curve analysis with an AUC value of 0.9089. Also, gene set enrichment analysis showed that CD40 is mainly involved in biological processes regulating immune response activation in GC. Further analysis of other prevalent cancer entities in TCGA showed that CD40 hypermethylation is a common event during tumor progression and could be considered as a potential biomarker for the detection of breast, colorectal, and prostate cancers as well.

SIGNIFICANCE

The finding of this study suggests that CD40 methylation as a potential pan biomarker could be a valuable target for liquid biopsy application of human cancers.

The impact of Harmine hydrochloride on growth, apoptosis and migration, invasion of gastric cancer cells

It has been reported that Harmine hydrochloride (HH) has an inhibitory effect on tumor cells, but the effect and mechanism of HH on gastric cancer cells remains unclear. The aim of this study was to investigate the effect and mechanism of HH on human gastric cancer cell line. In present study, results showed that HH could inhibit AGS, SGC7901 and HGC-27 cells in a time-dose-dependent manner (P < 0.01). Furthermore, this study demonstrated that more cells were arrested in G0/G1 phase, and apoptosis rate of AGS cells was significantly increased after HH treatment (P < 0.01). In addition, the study results showed that the mRNA and proteins of CyclinE, CyclinD1, PCNA declined dramatically, while p27, p21 increased significantly (P < 0.01). The results in this research also showed that the mRNA and proteins of Survivin and Bcl-2 decreased, while the expression of Bax, caspase-3, Bad increased significantly (P < 0.01). Also, the results of this study showed that invasion and migration of AGS cells decreased significantly after HH treatment (P < 0.01), with the expression of MMP-2, HIF-1 α and PRDX1 decreasing on observation after HH treatment (P < 0.01). In conclusion, HH has the property to inhibit GC cells via regulating GC cells' proliferation, apoptosis, invasion and migration.

Evaluation of Systemic Inflammatory Response and Nutritional Biomarkers as Predictive Factors in Patients with Recurrent Gastric Cancer

BACKGROUND

The present study sought to evaluate host-related factors as predictors in patients receiving chemotherapy for recurrent advanced gastric cancer.

METHODS

Sixty-three patients were enrolled in the study and received chemotherapy for recurrent gastric cancer at the Kochi Medical School from 2008 to 2015. Clinicopathological information and systemic inflammatory response data were obtained retrospectively to investigate associations between baseline cancer-related prognostic variables and survival outcomes.

RESULTS

The median survival time was significantly higher for patients with a Glasgow prognostic score (GPS) of 0 compared to a GPS of 1 or 2 (18.2 vs. 7.1 months; p = 0.006), and for patients in the normal range for carbohydrate antigen-125 (CA125) compared to higher levels (17.9 vs. 4.1 months; p = 0.003). There was no significant influence on overall survival by age, gender, disease status, metastatic site, time to recurrence, carcinoembryonic antigen level, CA19-9 level, prognostic nutrition index, or neutrophil to lymphocyte ratio according to the results of the univariate log-rank tests. Multivariate survival analysis identified a GPS of 1 or 2 (hazard ratio, 3.520; 95% confidence interval, 1.343-9.227; p = 0.010) and a high CA125 level (hazard ratio, 3.135; 95% confidence interval, 1.276-7.697; p = 0.013) as significant independent predictors associated with a poorer prognosis in the studied group of cancer patients.

CONCLUSIONS

A GPS of 1 or 2 and a high level of CA125 are independent predictors of a poorer prognosis in patients receiving chemotherapy for recurrent gastric cancer.