Comparative molecular subtypes of index and metachronous gastric adenocarcinomas: a study of 42 Korean patients

Distinct genomic, transcriptomic, and immune profiles for tumor and non-tumor mucosal regions in early gastric cancer

In early gastric cancer, local recurrence develops after endoscopic resection by field cancerization. Understanding the nature of cancer-prone environments is important to establish effective strategies to prevent recurrence. We hypothesized that the molecular/immune profiles in non-tumor (cancer-prone) tissue differ according to the relative distance from the gastric tumor. For this purpose, we performed whole-exome and transcriptome sequencing of 16 early gastric cancer samples with paired non-tumor mucosa 1 cm (N1) and 3 cm (N3) away from the tumor. The whole exome sequencing revealed mutations in both the tumor and non-tumor mucosa. TTN was the most frequently altered gene in tumors (31 %) and was the second most frequently altered gene in N1 (25 %) samples; however, the mutation rate was significantly lower in N3 (12 %) samples (P = 0.0046). Moreover, the expression levels of TTN mRNA were higher in tumors than in the N1 and N3 samples and were significantly associated with TTN mutations (P = 0.04). TP53 mutations were mainly observed in tumors (50 %) and in 6.3 % of N1, with no mutation detected in N3 samples. Transcriptome sequencing revealed that the expression of the epithelial-mesenchymal transition signature, mesenchymal signature, and proliferation signature was increased in tumors, whereas programmed death-ligand 1 expression was decreased in the non-tumor mucosa. In the tumor, although the numbers of M0/M1 macrophages, neutrophils, and eosinophils increased, plasma cell numbers were markedly decreased compared to non-tumor mucosa. In conclusion, non-tumor mucosa at 1 cm and 3 cm from the tumor harbored different genomic, transcriptomic, and immune cell profiles. The non-tumor mucosa closer to the tumor (1 cm) exhibited similar genomic and transcriptomic features. These findings can offer clinical guidance for acquiring a safe horizontal margin in endoscopic resection for early gastric cancer.

Investigating the relationship between Epstein-Barr virus infection and gastric cancer: A systematic review and meta-analysis

Background and Aims

Gastric cancer (GC) is a common cancer type worldwide, and various factors can be involved in its occurrence. One of these factors is Epstein-Barr virus (EBV) infection. In this regard, a systematic review and meta-analysis was conducted to achieve a better understanding of the EBV prevalence in GC samples.

Methods

English databases were searched and studies that reported the prevalence and etiological factors of EBV related to GC from July 2007 to November 2022 were retrieved. The reported data were selected based on the inclusion and exclusion criteria. The pooled prevalence of EBV infection with 95% confidence intervals was calculated. Quality assessment, heterogeneity testing, and publication bias assessment were also performed. The literature search showed 953 studies, of which 87 studies met our inclusion criteria and were used for meta-analysis.

Results

The pooled prevalence of EBV infection related to GC was estimated to be 9.5% (95% confidence interval [CI]: 8.2%-11%) in the general population. The prevalence of EBV infection related to GC by gender was 13.5% (95% CI: 11.1%-16.3%) in males and 7.6% (95% CI: 5.4%-10.6%) in females. No significant differences were observed in terms of geographical region. Out of the 87 studies included in the meta-analysis, the most common diagnostic test was in situ hybridization (58 cases).

Conclusions

Altogether, the results indicated that EBV infection is one of the important factors in the development of GC. However, this does not necessarily mean that EBV infection directly causes GC since other factors may also be involved in the development of GC. Therefore, it is recommended to conduct extensive epidemiological studies on various aspects of the relationship between this virus and GC, which can provide valuable information for understanding the relationship between EBV and GC.