Prognostic Biomarkers for Gastric Cancer: An Umbrella Review of the Evidence

A novel adenosine signalling-based prognostic signature in gastric cancer and its association with cancer immune features and immunotherapy response

Reliable prognostic signatures that can reflect the intrinsic characteristics of gastric cancer (GC) are still rare. Here, we developed an adenosine-based prognostic signature and explored its association with the tumour immune in GC patients, aiming at confirming the prognostic value of adenosine-related genes and guiding the GC risk stratification and immunotherapeutic response prediction. We collected adenosine pathway-related genes from STRING websites and manual searching. We enrolled the The Cancer Genome Atlas cohort and four gene expression omnibus cohorts of GC for generating and validating the adenosine pathway-based signature using the Cox regression method. Gene expression in the signature was verified using polymerase chain reaction. We also performed gene set enrichment analysis, immune infiltration assessment and immunotherapy response prediction based on this signature. Our study resulted in a six-gene adenosine signature (GNAS, CXCR4, PPP1R1B, ADCY6, NT5E and NOS3) for risk stratification of GC prognosis, with the highest area under the receiver operating characteristic curve up to 0.767 for predicting 10-year overall survival (OS). In the training cohort, patients with signature-defined high risk had significantly poorer OS than those with low risk (p < .001). Multivariate analysis identified the signature as an independent prognostic factor (hazard ratio 2.863, 95% confidence interval [1.871-4.381], p < .001). These findings were confirmed in four independent cohorts. Expression detection showed that all signature genes were upregulated in both GC tissues and cell lines. Further analysis revealed that the signature-defined high-risk patients were characterised by immunosuppressive states and associated with a poor immunotherapy response. In conclusion, the adenosine pathway-based signature represents a promising risk stratification tool for GC in guiding individualised prognostication and immunotherapy.

Preoperative peripheral blood inflammatory markers especially the fibrinogen-to-lymphocyte ratio and novel FLR-N score predict the prognosis of patients with early-stage resectable extrahepatic cholangiocarcinoma

Background

Systemic inflammation is important in the development of extrahepatic cholangiocarcinoma (ECC). The aim of this study was to compare the prognostic power of preoperative peripheral blood inflammatory markers and the novel FLR-N score in patients with resectable ECC.

Methods

A total of 140 patients with resectable ECC and 140 healthy controls (HCs) were recruited for the study. The Mann−Whitney U test was used to evaluate the differences in inflammatory markers between groups. Kaplan−Meier and Cox regression analyses were used to evaluate the prognostic power of preoperative fibrinogen, albumin, prealbumin, bilirubin, neutrophils, lymphocytes, monocytes, platelets, fibrinogen-to-lymphocyte ratio (FLR), fibrinogen-to-albumin ratio (FAR), fibrinogen-to-prealbumin ratio (FPR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), FLR-neutrophil (FLR-N) score, and CA19-9 in patients with resectable ECC. Nomogram was developed based on the results of multivariate Cox analyses.

Results

Patients with resectable ECC had significantly higher levels of neutrophils, monocytes, fibrinogen, FLR, FAR, FPR, NLR, PLR, and MLR and lower levels of lymphocytes, albumin, and prealbumin than HCs (all P < 0.01). Albumin, prealbumin, and FPR had a good ability to distinguish between ECC patients with total bilirubin < 34 µmol/L and HCs (AUCs of 0.820, 0.827, and 0.836, respectively). Kaplan−Meier analysis showed that high neutrophil, fibrinogen, FLR, FAR, PLR, MLR, and FLR-N score values were associated with poor survival in patients with resectable ECC. Multivariate analyses indicated that neutrophils (P = 0.022), FLR (P = 0.040), FLR-N score (P < 0.0001), and positive lymph node metastasis (P = 0.016) were independent factors for overall survival (OS). Nomogram were developed to predict OS for patients with ECC.

Conclusion

The prognostic roles of inflammatory markers in patients with resectable ECC were different. The preoperative neutrophil count, FLR and FLR-N score could serve as noninvasive markers for predicting the prognosis of resectable ECC.

Methodological approaches for assessing certainty of the evidence in umbrella reviews: A scoping review

Introduction

The number of umbrella reviews (URs) that compiled systematic reviews and meta-analysis (SR-MAs) has increased dramatically over recent years. No formal guidance for assessing the certainty of evidence in URs of meta-analyses exists nowadays. URs of non-interventional studies help establish evidence linking exposure to certain health outcomes in a population. This study aims to identify and describe the methodological approaches for assessing the certainty of the evidence in published URs of non-interventions.

Methods

We searched from 3 databases including PubMed, Embase, and The Cochrane Library from May 2010 to September 2021. We included URs that included SR-MAs of studies with non-interventions. Two independent reviewers screened and extracted data. We compared URs characteristics stratified by publication year, journal ranking, journal impact factor using Chi-square test.

Results

Ninety-nine URs have been included. Most were SR-MAs of observational studies evaluating association of non-modifiable risk factors with some outcomes. Only half (56.6%) of the included URs assessed the certainty of the evidence. The most frequently used criteria is credibility assessment (80.4%), followed by GRADE approach (14.3%). URs published in journals with higher journal impact factor assessed certainty of evidence than URs published in lower impact group (77.1 versus 37.2% respectively, p < 0.05). However, criteria for credibility assessment used in four of the seven URs that were published in top ranking journals were slightly varied.

Conclusions

Half of URs of MAs of non-interventional studies have assessed the certainty of the evidence, in which criteria for credibility assessment was the commonly used method. Guidance and standards are required to ensure the methodological rigor and consistency of certainty of evidence assessment for URs.

Cost-effective low-coverage whole-genome sequencing assay for the risk stratification of gastric cancer

BACKGROUND

Gastric cancer (GC), a multifactorial disease, is caused by pathogens, such as Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV), and genetic components.

AIM

To investigate microbiomes and host genome instability by cost-effective, low-coverage whole-genome sequencing, as biomarkers for GC subtyping.

METHODS

Samples from 40 GC patients were collected from Taizhou Hospital, Zhejiang Province, affiliated with Wenzhou Medical University. DNA from the samples was subjected to low-coverage whole-genome sequencing with a median genome coverage of 1.86 × (range: 1.03 × to 3.17 ×) by Illumina × 10, followed by copy number analyses using a customized bioinformatics workflow ultrasensitive chromosomal aneuploidy detector.

RESULTS

Of the 40 GC samples, 20 (50%) were found to be enriched with microbiomes. EBV DNA was detected in 5 GC patients (12.5%). H. pylori DNA was found in 15 (37.5%) patients. The other 20 (50%) patients were found to have relatively higher genomic instability. Copy number amplifications of the oncogenes, ERBB2 and KRAS, were found in 9 (22.5%) and 7 (17.5%) of the GC samples, respectively. EBV enrichment was found to be associated with tumors in the gastric cardia and fundus. H. pylori enrichment was found to be associated with tumors in the pylorus and antrum. Tumors with elevated genomic instability showed no localization and could be observed in any location. Additionally, H. pylori-enriched GC was found to be associated with the Borrmann type II/III and gastritis history. EBV-enriched GC was not associated with gastritis. No statistically significant correlation was observed between genomic instability and gastritis. Furthermore, these three different molecular subtypes showed distinct survival outcomes (P = 0.019). EBV-positive tumors had the best prognosis, whereas patients with high genomic instability (CIN+) showed the worst survival. Patients with H. pylori infection showed intermediate prognosis compared with the other two subtypes.

CONCLUSION

Thus, using low-coverage whole-genome sequencing, GC can be classified into three categories based on disease etiology; this classification may prove useful for GC diagnosis and precision medicine.

Validity of observational evidence on putative risk and protective factors: appraisal of 3744 meta-analyses on 57 topics

BACKGROUND

The validity of observational studies and their meta-analyses is contested. Here, we aimed to appraise thousands of meta-analyses of observational studies using a pre-specified set of quantitative criteria that assess the significance, amount, consistency, and bias of the evidence. We also aimed to compare results from meta-analyses of observational studies against meta-analyses of randomized controlled trials (RCTs) and Mendelian randomization (MR) studies.

METHODS

We retrieved from PubMed (last update, November 19, 2020) umbrella reviews including meta-analyses of observational studies assessing putative risk or protective factors, regardless of the nature of the exposure and health outcome. We extracted information on 7 quantitative criteria that reflect the level of statistical support, the amount of data, the consistency across different studies, and hints pointing to potential bias. These criteria were level of statistical significance (pre-categorized according to 10^-6, 0.001, and 0.05 p-value thresholds), sample size, statistical significance for the largest study, 95% prediction intervals, between-study heterogeneity, and the results of tests for small study effects and for excess significance.

RESULTS

3744 associations (in 57 umbrella reviews) assessed by a median number of 7 (interquartile range 4 to 11) observational studies were eligible. Most associations were statistically significant at P < 0.05 (61.1%, 2289/3744). Only 2.6% of associations had P < 10^-6, ≥1000 cases (or ≥20,000 participants for continuous factors), P < 0.05 in the largest study, 95% prediction interval excluding the null, and no large between-study heterogeneity, small study effects, or excess significance. Across the 57 topics, large heterogeneity was observed in the proportion of associations fulfilling various quantitative criteria. The quantitative criteria were mostly independent from one another. Across 62 associations assessed in both RCTs and in observational studies, 37.1% had effect estimates in opposite directions and 43.5% had effect estimates differing beyond chance in the two designs. Across 94 comparisons assessed in both MR and observational studies, such discrepancies occurred in 30.8% and 54.7%, respectively.

CONCLUSIONS

Acknowledging that no gold-standard exists to judge whether an observational association is genuine, statistically significant results are common in observational studies, but they are rarely convincing or corroborated by randomized evidence.

Combination of preoperative red cell distribution width and neutrophil to lymphocyte ratio as a prognostic marker for gastric cancer patients

Background

The neutrophil to lymphocyte ratio (NLR) and red blood cell distribution width (RDW) play an important role in the prognosis of several cancers, but their prognostic value in patients with stage II-III gastric cancer (GC) is unclear. We aimed to evaluate the prognostic value of the RDW-NLR (R-NLR) score based on RDW and NLR in stage II-III GC patients after radical surgery.

Methods

Preoperative RDW and NLR clinicopathological data were retrospectively reviewed and analyzed from stage II-III GC patients who underwent radical gastrectomy. The optimal cut-off values for pre-RDW-variation coefficient (pre-RDW-cv) and pre-NLR were defined as 14.10% and 2.015, respectively. The R-NLR score was defined as 2 (both elevated RDW and NLR), 1 (one of these was elevated), or 0 (neither were elevated). Prognostic factors were identified by univariate and multivariate analyses.

Results

A total of 151 patients were included in this study, and 65 (43.05%), 54 (35.76%), and 32 (21.19%) patients had an R-NLR score of 0, 1 and 2, respectively. The preoperative R-NLR score was significantly correlated with tumor size and gender (all P<0.05). The 5-year overall survival (OS) in the R-NLR 0, 1, and 2 groups was 52.30%, 44.40%, and 31.20%, respectively (P=0.031), while the 5-year DFS was 47.70%, 13.30%, and 18.80%, respectively (P<0.001). Further, while the 5-year disease-free survival (DFS) rate was significantly improved in low RDW-cv and NLR patients compared with those with high RDW-cv and NLR (all P<0.05), but not OS (all P>0.05). Multivariate analysis demonstrated that the R-NLR score was independently correlated with OS [hazard ratio (HR), 1.527; P=0.007] and DFS (HR, 1.939; P=0.001).

Conclusions

We validated the preoperative R-NLR score to be a promising predictor for stage II-III GC patients who have undergone radical gastrectomy.

Decreased expression of TRIM3 gene predicts a poor prognosis in gastric cancer

BACKGROUND/AIMS

Tripartite motif-containing 3 (TRIM3) is a member of the TRIM protein family which is known to be involved in development of numerous tumor types. However, the prognostic role of TRIM3 in gastric cancer (GC) remained to be clarified. The aim of this study was to evaluate the expression pattern and prognostic significance of TRIM3 gene and its relationship with β-catenin, CyclinD, and BCL2 expression in patients with GC.

METHODS

A total of 40 fresh primary gastric cancer tumors and their matched adjacent noncancerous tissues were selected from the First Affiliated Hospital of Mashhad University. Real-time quantitative RT-PCR was performed to evaluate differences in TRIM3 expression in GC and normal tissues. The correlation between TRIM3 expression level and patients' overall survival, some clinicopathological variables, and β-catenin, CyclinD, and BCL-2 genes expression level were also studied. Moreover, patients were divided in two groups according to the TRIM3 expression levels: low and high.

RESULTS

Compared to noncancerous tissues, TRIM3 expression in GC tissues was significantly increased (fold change = 1.58). Kaplan-Meier survival analysis revealed a significant difference of patient survival according to TRIM3 expression status (P = 0.012). Low TRIM3 expression was associated with shorter overall survival and was an independent predictor for poor prognosis in GC patients (HR, 1.25; 95%CI, 1.02-1.60; P = 0.045). Expression of TRIM3 was negatively correlated with expression of β-catenin, BCL-2, and CyclinD as genes for proliferation, apoptosis, and the cell cycle in GC patients.

CONCLUSIONS

This study demonstrates that decreased level of TRIM3 mRNA expression is associated with poor prognosis in patients with gastric cancer. TRIM3 may play a protective role in gastric cancer by relieving the effects of cancer progressive genes and could be considered for further investigations as a prognostic biomarker.