Optimising Multimodality Treatment of Resectable Oesophago-Gastric Adenocarcinoma

Establishment and validation of a prognostic scoring model based on disulfidptosis-related long non-coding RNAs in stomach adenocarcinoma

Background

Stomach adenocarcinoma (STAD), a frequently occurring gastrointestinal tumour, is often detected late and has a poor prognosis. Long non-coding RNAs (lncRNAs) significantly affect tumour development. Recent studies have identified disulfidptosis as a previously unexplained form of cell death. Herein, we aimed to examine the predictive value of disulfidptosis-related lncRNA models for the clinical prognosis and immunotherapy of STAD.

Methods

STAD-related transcriptomic data were obtained from The Cancer Genome Atlas (TCGA), whereas genes associated with disulfidptosis were identified from previously published papers. A risk prediction model for disulfidptosis-related lncRNAs was developed using the Cox regression and least absolute shrinkage selection algorithm methods. The accuracy of the model was confirmed using calibration curves, and the biological functions were analysed using Gene Ontology (GO) and Gene Set Enrichment Analysis (GSEA). Finally, the tumour mutation burden (TMB) and tumour immune dysfunction and exclusion (TIDE) algorithms were used to screen drugs that are sensitive to STAD.

Results

The risk prediction models were constructed using seven disulfidptosis-related lncRNAs. The validated results were consistent with the predicted ones, with significant survival differences. When combined with clinical data, the risk scores were used as independent prognostic markers. Based on the tumour mutation load, the high-risk patient group had a poorer survival rate as compared with the low-risk patient group. Further studies were conducted to understand the different groups' inconsistent responses to immune status; subsequently, relatively sensitive drugs were identified.

Conclusions

Overall, seven markers of disulfidptosis-related lncRNAs associated with STAD were found to facilitate prognostic prediction, suggesting new ideas for immunotherapy and clinical applications.

Current management of gastric adenocarcinoma: a narrative review

Gastric adenocarcinoma is a leading cause of cancer death worldwide. The management of this aggressive malignancy largely depends on tumor characteristics especially stage. Superficial early-stage gastric cancer can be safely managed by endoscopic resection, though clear negative deep and lateral margins must be obtained. Optimal surgical resection is an essential part of the treatment for locally advanced gastric adenocarcinoma, with perioperative and adjuvant therapies having significant impact on long-term outcomes. Chemoradiation is reserved for patients with suboptimal surgical resection. Recent therapeutic advances have prolonged survival in patients with metastatic gastric adenocarcinoma, include checkpoint inhibitors and biomarker-directed therapy. Targeted therapies in gastric adenocarcinoma include monoclonal antibodies directed against vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor-2 (VEGFR-2), and human epidermal growth factor receptor 2 (HER2). While anti-VEGF therapies were not found beneficial in the perioperative setting, the effectiveness of HER2 targeted agents in resectable HER2-positive gastric adenocarcinoma is being studied. Microsatellite instability (MSI) varies greatly in patients with gastric adenocarcinoma between 5-20% based on ethnic origin, tumour heterogeneity and staging. The role chemotherapy in the perioperative setting for patients with MSI-high tumors remains controversial while immunotherapy demonstrates promising results in preliminary studies. Immune checkpoint inhibitors in combination with chemotherapy has been shown to improve outcomes in patients with metastatic gastric adenocarcinoma who express programmed cell death 1 ligand 1 (PD-L1) and is now being investigated in the perioperative setting.

Prognostic Factors and the Role of Adjuvant Chemotherapy in Pathological Node-Negative T3 Gastric Cancer

The role of adjuvant chemotherapy in pathological T3N0M0 (pT3N0M0) gastric cancer (GC) remains unclear. The aim of this study was to analyze the prognostic factors of patients with pT3N0M0 GC and to clarify which ones could benefit from adjuvant chemotherapy. A total of 137 patients with pT3N0M0 GC were recruited between 1994 and 2020. Clinicopathological factors and adjuvant chemotherapy regimens were retrospectively collected. Prognostic factors of disease-free survival (DFS) and cancer-specific survival (CSS) were determined using univariate and multivariate analyses. The chemotherapy group was younger (p = 0.012), had had more lymph nodes retrieved (p = 0.042) and had higher percentages of vascular invasion (p = 0.021) or perineural invasion (p = 0.030) than the non-chemotherapy group. There were no significant differences in DFS (p = 0.222) and CSS (p = 0.126) between patients treated with or without adjuvant chemotherapy. Stump cancer, tumor size and perineural invasion were associated with higher rates of recurrence. Tumor size was an independent prognostic factor for DFS (hazard ratio, 4.55; confidence interval, 1.59-12.99; p = 0.005) and CSS (hazard ratio, 3.97; confidence interval, 1.38-11.43; p = 0.011). Tumor size independently influenced survival outcomes in pT3N0M0 patients who underwent radical surgery with and without adjuvant chemotherapy.

Association of the TGFβ gene family with microenvironmental features of gastric cancer and prediction of response to immunotherapy

In the complex tumor microenvironment, TGFβ is a pleiotropic cytokine involved in regulating cellular processes such as cancer cell proliferation, apoptosis and metastasis. TGFβ defines three subtypes (TGFβ1, TGFβ2, and TGFβ3), of which TGFβ is highly expressed in many cancers, especially those showing high dissemination potential. In addition, increased expression of TGFβ in multiple cancers is usually positively correlated with epithelial mesenchymal transition (EMT) and coordinated with the expression of genes driving EMT-related genes. TGFβ signaling in the tumor microenvironment inhibits the antitumor function of multiple immune cell populations, including T cells and natural killer cells, and the resulting immunosuppression severely limits the efficacy of immune checkpoint inhibitors and other immunotherapeutic approaches. As a major pathway to enhance the efficacy of cancer immunotherapy effects, the role of TGFβ signaling inhibitors have been evaluated in many clinical trials. However, the potential functions and mechanisms of TGFβ1, TGFβ2 and TGFβ3 in gastric cancer progression and tumor immunology are unclear. In this study, we comprehensively analyzed TGFβ1, TGFβ2 and TGFβ3 and gastric cancer microenvironmental features, including immune cell infiltration, EMT, hypoxia, mutation, immunotherapy and drug treatment, based on HMUCH sequencing data (GSE184336) and public databases. We also validated the protein expression levels of TGFβ in gastric cancer tissues as well as the role of TGFβ factor in cytology experiments. This report reveals the important role of the TGFβ gene family in gastric cancer and provides possible relationships and potential mechanisms of TGFβ in gastric cancer.