Clinicopathological characteristics, survival outcome and prognostic factors of very young gastric cancer

Spatial transcriptomic characteristics of gastric cancer in young and the expression and role of TMEM176B in gastric cancer cells

BACKGROUND

Gastric cancer in young (GCY) is increasing in incidence with poor prognosis. Current screening and molecular methods are inadequate, necessitating new approaches to explore its pathogenesis. This study used spatial transcriptomic sequencing (ST-seq) to analyze the cellular composition of gastric cancer (GC) tumors, compare gene expression patterns, explore signaling pathways, and investigate the role of the differentially expressed gene (DEG) TMEM176B in GCY.

METHODS

The surgical specimens of six patients with GCY were included to construct a tissue microarray containing the tumor core region (TCR), cancer-adjacent tissue (CAT), and normal gastric tissue (NGT). ST-seq was performed to obtain the transcript expression levels at different spatial locations. After quality control, normalization, standardization, clustering, dimensionality reduction, and cell-type prediction analyses were carried out to identify the DEGs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used to clarify the underlying mechanisms of GC. Based on the results, TMEM176B was selected for functional analysis. Western blotting was used to assess TMEM176B expression in normal gastric cells and cancerous cells. shRNA-mediated TMEM176B knockdown in cancer cells was used for phenotypic analysis, proliferation assays, and apoptosis experiments.

RESULTS

This study identified heterogeneous cell populations in GCY tissues. Exactly 18,082 DEGs were found between the TCR and CAT, mainly enriched in the IL-17, AGE-RAGE, and relaxin pathways. Moreover, 17,586 DEGs were identified between the TCR and NGT, primarily related to the HIF-1 and apoptosis pathways. TMEM176B was a key DEG in the TCR vs. CAT and TCR vs. NGT comparisons. It was highly expressed in GCY tissues and GC cell lines. Further analysis using The Cancer Genome Atlas database confirmed its oncogenic effects. TMEM176B knockdown in GC cell lines inhibited cell proliferation (reduced CCK8 and colony formation), increased apoptosis (higher Bax/Bcl2 ratio), and arrested the cell cycle in the G0/G1 phase.

CONCLUSIONS

This study used ST-seq to map the transcriptomic profiles of the TCR, CAT, and NGT in patients with GCY, investigating gene spatial expression patterns and tumor heterogeneity. We identified TMEM176B's role in GC development and progression, offering molecular targets and a foundation for future treatments.

Global burden of young-onset gastric cancer: a systematic trend analysis of the global burden of disease study 2019

BACKGROUND

While gastric cancer is generally declining globally, the temporal trend of young-onset (< 40 years) gastric cancer remains uncertain. We performed this analysis to determine the temporal trends of young-onset gastric cancer compared to late-onset cancer (≥ 40 years).

METHODS

We extracted cross-sectional data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. The burden of gastric cancer from 1990 to 2019 was assessed through indicators including incidence and mortality rates, which were classified at global, national, and regional levels, and according to socio-demographic indexes (SDI) and age or sex groups. Joinpoint regression analysis was used to identify specific years with significant changes. The correlation between AAPC with countries' average SDI was tested by Pearson's Test.

RESULTS

The global incidence rate of young-onset gastric cancer decreased from 2.20 (per 100,000) in 1990 to 1.65 in 2019 (AAPC: - 0.95; 95% confidence interval [CI] - 1.25 to - 0.65; P < 0.001). Late-onset cancer incidence also decreased from 59.53 (per 100,000) in 1990 to 41.26 in 2019 (AAPC: - 1.23; 95% CI - 1.39 to - 1.06, P < 0.001). Despite an overall decreasing trend, the incidence rate of young-onset cancer demonstrated a significant increase from 2015 to 2019 (annual percentage change [APC]: 1.39; 95% CI 0.06 to 2.74; P = 0.041), whereas no upward trend was observed in late-onset cancer. Mortality rates of young- and late-onset cancer both exhibited a significant decline during this period (AAPC: - 1.82; 95% CI - 2.15 to - 1.56; P < 0.001 and AAPC: - 1.69, 95% CI - 1.79 to - 1.59; P < 0.001). The male-to-female rate ratio for incidence and mortality in both age groups have been increasing since 1990. While countries with high SDI have had a greater decline in the incidence of late-onset gastric cancer (slope of AAPC change: - 0.20, P = 0.004), it was not observed in young-onset cancer (slope of AAPC change: - 0.11, P = 0.13).

CONCLUSIONS

The global incidence and mortality rates of both young- and late-onset gastric cancer have decreased since 1990. However, the incidence rate of young-onset cancer has demonstrated a small but significant upward trend since 2015. There was disparity in the decline in young-onset gastric cancer among male and high SDI countries. These findings could help to inform future strategies in preventing gastric cancer in younger individuals.

Identification and validation of key genes in gastric cancer: insights from in silico analysis, clinical samples, and functional assays

INTRODUCTION

The underlying mechanisms of gastric cancer (GC) remain unknown. Therefore, in this study, we employed a comprehensive approach, combining computational and experimental methods, to identify potential key genes and unveil the underlying pathogenesis and prognosis of GC.

METHODS

Gene expression profiles from GEO databases (GSE118916, GSE79973, and GSE29272) were analyzed to identify DEGs between GC and normal tissues. A PPI network was constructed using STRING and Cytoscape, followed by hub gene identification with CytoHubba. Investigations included expression and promoter methylation analysis, survival modeling, mutational and miRNA analysis, gene enrichment, drug prediction, and in vitro assays for cellular behaviors.

RESULTS

A total of 83 DEGs were identified in the three datasets, comprising 41 up-regulated genes and 42 down-regulated genes. Utilizing the degree and MCC methods, we identified four hub genes that were hypomethylated and up-regulated: COL1A1, COL1A2, COL3A1, and FN1. Subsequent validation of their expression and promoter methylation on clinical GC samples through targeted bisulfite sequencing and RT-qPCR analysis further confirmed the hypomethylation and overexpression of these genes in local GC patients. Furthermore, it was observed that these hub genes regulate tumor proliferation and metastasis in in vivo and exhibited mutations in GC patients.

CONCLUSION

We found four potential diagnostic and prognostic biomarkers, including COL1A1, COL1A2, COL3A1, and FN1 that may be involved in the occurrence and progression of GC.

Clinicopathological Characteristics and Risk Factors of Young-Onset Gastric Carcinoma: A Systematic Review and Meta-analysis

INTRODUCTION

The characteristics of gastric carcinoma in young individuals differ from that in older individuals. We conducted a systematic review and meta-analysis to explore the clinicopathological features and risk factors associated with young-onset (younger than 50 years) gastric carcinoma.

METHODS

We searched for studies published between January 1, 1990, and September 1, 2023, on patients with young-onset gastric carcinoma in PubMed, EMBASE, Web of Science, and MEDLINE to explore clinicopathological characteristics among this specific patient group. Extracted information included the proportion of patients with symptoms or family history of gastric cancer, tumor location, and histological features such as Lauren or World Health Organization histological classification and degree of differentiation. Additional analyses were conducted on risk factors such as positive family history, Helicobacter pylori infection, or high-risk nutritional or behavioral factors. The estimates were derived using random or fixed-effect models and included subgroup analyses based on different sex and age groups. This study was registered in PROSPERO (CRD42023466131).

RESULTS

We identified 5,696 records, 1,292 were included in the quality assessment stage. Finally, 84 studies from 18 countries or regions including 89,447 patients with young-onset gastric carcinoma were included. Young-onset gastric carcinoma has slight female predominance (53.7%, 95% confidence interval [CI]: 51.6-55.7%), with most having symptoms (87.0%, 95% CI: 82.4%-91.7%). Family history was reported in 12.1% (95% CI: 9.5%-14.7%). H. pylori infection was detected in 60.0% of cases (95% CI: 47.1%-72.8%). Most of these carcinomas were in the non-cardia region (89.6%, 95% CI: 82.4%-96.8%), exhibiting Lauren diffuse-type histology (71.1%, 95% CI: 66.8%-75.3%) and poor/undifferentiated features (81.9%, 95% CI%: 79.7-84.2%). A positive family history of gastric cancer was the most important risk factor associated with the development of gastric carcinoma in young individuals (pooled odds ratios 4.0, 95% CI: 2.8-5.2), followed by H. pylori infection (odds ratio 2.3; 95% CI: 1.4-3.2) and dietary and other lifestyle risk factors.

DISCUSSION

Young-onset gastric carcinoma exhibits specific clinicopathological characteristics, with positive family history being the most important risk factor. Most of the patients were symptomatic at diagnosis. These findings could help to inform future strategies for the early detection of gastric carcinoma among young individuals.

Efficacy and safety of chemotherapy in young patients with advanced gastroesophageal adenocarcinoma: data from the Spanish AGAMENON-SEOM registry

BACKGROUND

Gastroesophageal adenocarcinoma in young adults (GCYA) counts for 10-15% of diagnoses. Previous studies have mainly focused on surgical outcomes in patients with resectable tumors; however, systemic therapy for advanced GCYA remains under-evaluated. This study aims to assess the efficacy-related outcomes and safety of first-line chemotherapy (CT) in younger versus older patients with advanced gastroesophageal adenocarcinoma.

METHODS

Patients with advanced gastroesophageal adenocarcinoma from the AGAMENON-SEOM registry treated with first-line polychemotherapy between January 2008 and October 2022 were included. We compared clinicopathological features, therapies received, efficacy-related outcomes, and toxicity between individuals aged < and ≥ 45 years.

RESULTS

Out of 3386 patients, 263 (7.8%) were < 45 years. Young patients exhibited a higher proportion of females affected, lower ECOG-PS ≥ 2, fewer comorbidities, and more aggressive disease-related features, such as higher proportion of diffuse subtype, signet-ring cells, plastic linitis, grade 3, peritoneal metastases and metastatic disease at diagnosis. They received more triple-agent combinations and underwent more surgeries in metastatic setting. No significant differences were observed between groups in overall response rate (53.1% vs. 52.3% in < and ≥ 45 years, respectively, p = 0.579), progression-free survival (6.1 vs. 6.83 months, p = 0.158) and overall survival (11.07 vs. 10.81 months, p = 0.82), even after adjusting for potential confounding factors. Grade 3-4 adverse events were comparable in both groups, although toxicity leading to treatment discontinuation was more frequent in older patients.

CONCLUSIONS

In the AGAMENON-SEOM registry, younger patients with GCYA exhibited more aggressive clinicopathological features, and despite receiving more aggressive treatments, similar efficacy outcomes and toxicity profiles were achieved compared to their older counterparts. In the AGAMENON-SEOM registry, GEAC in < 45 years showed more aggressive clinicopathological features and, although treated with more intense first-line CT regimens, similar efficacy outcomes and toxicity were achieved compared to older patients.

Development and validation of nomogram models to predict radiotherapy or chemotherapy benefit in stage III/IV gastric adenocarcinoma with surgery

Objectives

The advanced gastric adenocarcinoma (GAC) patients (stage III/IV) with surgery may have inconsistent prognoses due to different demographic and clinicopathological factors. In this retrospective study, we developed clinical prediction models for estimating the overall survival (OS) and cancer-specific survival (CSS) in advanced GAC patients with surgery.

Methods

A retrospective analysis was conducted using the Surveillance, Epidemiology, and End Results (SEER) database. The total population from 2004 to 2015 was divided into four levels according to age, of which 179 were younger than 45 years old, 695 were 45-59 years old, 1064 were 60-74 years old, and 708 were older than 75 years old. There were 1,712 men and 934 women. Univariate and multivariate Cox regression analyses were performed to identify prognostic factors for OS and CSS. Nomograms were constructed to predict the 1-, 3-, and 5-year OS and CSS. The models' calibration and discrimination efficiency were validated. Discrimination and accuracy were evaluated using the consistency index, area under the receiver operating characteristic curve, and calibration plots; and clinical usefulness was assessed using decision curve analysis. Cross-validation was also conducted to evaluate the accuracy and stability of the models. Prognostic factors identified by Cox regression were analyzed using Kaplan-Meier survival analysis.

Results

A total of 2,646 patients were included in our OS study. Age, primary site, differentiation grade, AJCC 6th_TNM stage, chemotherapy, radiotherapy, and number of regional nodes examined were identified as prognostic factors for OS in advanced GAC patients with surgery (P < 0.05). A total of 2,369 patients were included in our CSS study. Age, primary site, differentiation grade, AJCC 6th_TNM stage, chemotherapy, radiotherapy, and number of regional nodes examined were identified as risk factors for CSS in these patients (P < 0.05). These factors were used to construct the nomogram to predict the 1-, 3-, and 5-year OS and CSS of advanced GAC patients with surgery. The consistency index and area under the receiver operating characteristic curve demonstrated that the models effectively differentiated between events and nonevents. The calibration plots for 1-, 3-, and 5-year OS and CSS probability showed good consistence between the predicted and the actual events. The decision curve analysis indicated that the nomogram had higher clinical predictive value and more significant net gain than AJCC 6th_TNM stage in predicting OS and CSS of advanced GAC patients with surgery. Cross-validation also revealed good accuracy and stability of the models.

Conclusion

The developed predictive models provided available prognostic estimates for advanced GAC patients with surgery. Our findings suggested that both OS and CSS can benefit from chemotherapy or radiotherapy in these patients.