Immunotherapy of gastric cancer: Present status and future perspectives

DNA methyltransferase 3A: A prognostic biomarker and potential target for immunotherapy in gastric cancer

DNA methyltransferase 3A (DNMT3A) has been associated with the occurrence or progression of various tumors, including gastric cancer. However, the role of DNMT3A in the efficacy of immune-cell infiltration in the tumor microenvironment and immunotherapy in gastric cancer remains less explored. DNMT3A expression level was analyzed using TIMER 2.0, Sangerbox 3.0, and The Cancer Genome Atlas database and further verified by immunohistochemical staining and RT-qPCR. The UALCAN, chi-square test, and Kaplan-Meier plotter databases were performed to assess the correlation of DNMT3A with clinicopathological characteristics and prognosis. The GeneMANIA database, STRING database, and R package were used to construct a DNMT3A co-expression gene network. Gene set enrichment analysis was used to identify the signaling pathways related to DNMT3A expression. The correlations between DNMT3A and cancer immune infiltrates were investigated using TIMER 2.0, Sangerbox 3.0, Kaplan-Meier Plotter, R package, and TISIDB databases. The TISIDB database and R package were used to construct the correlation between DNMT3A and immunomodulators and Immune cell Proportion Score. The association of DNMT3A expression with tumor mutational burden (TMB), microsatellite instability, and tumor dryness was evaluated using the TMB function of the R package, TIMER 2.0. Finally, the biological function of DNMT3A in gastric cancer cells was further assessed by CCK-8, cloning formation, and transwell assay. DNMT3A expression was remarkably upregulated in gastric cancer. The high expression of DNMT3A was associated with poor clinical features and poor survival in patients with gastric cancer. Moreover, gene set enrichment analyses showed that DNMT3A and its related genes were involved in various pathways that promoted cancer occurrence and progression by influencing the tumor microenvironment. Finally, DNMT3A was significantly related to tumor-infiltrating immune cells, immunomodulators, TMB, microsatellite instability, and immune checkpoints in gastric cancer. Moreover, knockdown of DNMT3A reduced the proliferation and migration of gastric cancer cells. Our findings highlight the potential of DNMT3A as a prognosis biomarker and an immunotherapeutic target for gastric cancer.

Targeted therapy and immunotherapy for gastric cancer: rational strategies, novel advancements, challenges, and future perspectives

Gastric cancer (GC) is one of the most common malignant tumors worldwide, and its treatment has been a focus of medical research. Herein we systematically review the current status of and advancements in targeted therapy and immunotherapy for GC, which have emerged as important treatment strategies in recent years with great potential, and summarize the efficacy and safety of such treatments. Targeted therapies against key targets in GC, including epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR), have shown remarkable therapeutic efficacies by inhibiting tumor progression and/or blood supply. In particular, markable breakthroughs have been made in HER2-targeting drugs for HER2-positive GC patients. To address intrinsic and acquired resistances to HER2-targeting drugs, novel therapeutic agents including bispecific antibodies and antibody-drug conjugates (ADC) targeting HER2 have been developed. Immunotherapy enhances the recognition and elimination of cancer cells by activating body anticancer immune system. Programmed cell death protein 1 (PD-1) and programmed cell death-ligand 1 (PD-L1) antibodies are the most commonly used immunotherapeutic agents and have been used with some success in GC treatment. Innovative immunotherapy modalities, including adoptive immune cell therapy, tumor vaccines, and non-specific immunomodulators therapy, and oncolytic viruses have shown promise in early-stage clinical trials for GC. Clinical trials have supported that targeted therapy and immunotherapy can significantly improve the survival and quality of life of GC patients. However, the effects of such therapies need to be further improved and more personalized, with advancement in researches on tumor immune microenvironment. Further studies remain needed to address the issues of drug resistance and adverse events pertaining to such therapies for GC. The combined application of such therapies and individualized treatment strategies should be further explored with novel drugs developed, to provide more effective treatments for GC patients.

Targeted and combination immunotherapies using biologics for gastric cancer: the state-of-the-art

INTRODUCTION

Gastric adenocarcinoma (GAC) remains a prevalent cancer worldwide and its incidence is increasing in South America. The heterogenous nature of GAC makes advances in management challenging.

AREAS COVERED

Despite challenges, recent therapeutic targets are individualizing treatment. For localized disease with microsatellite-instability-high/deficient mismatch repair, immunotherapy is now an adopted practice. In the advanced unresectable setting, those harboring human epidermal growth factor receptor-2 (HER2) expression continue to be a separate entity.

EXPERT OPINION

Future targets are developing. Among these include claudin 18.2 (CLDN18.2), fibroblast growth factor receptor 2b (FGFR2b), and trophoblast cell surface antigen-2 (TROP-2). FDA approval of zolbetuximab's, an anti-CLDN 18.2 monoclonal antibody, is expected soon. Additionally, bemarituzumab, ananti-FGFR2b monoclonal antibody, has shown improvements in combination with chemotherapy in those with HER2 negative GAC with FGFR2 overexpression. This combination is now being investigated in a phase 3 trial. Lastly, TROP-2 has emerged as an exciting solid tumor target and study is expected in GAC. All three of these therapeutic targets have seen an abundance of drug development in recent years, and we anticipate newer targeted agents driving therapeutic decisions in GAC in the coming years.

Predictive Factors of Immunotherapy in Gastric Cancer: A 2024 Update

Many studies on gastric cancer treatment have identified predictors of immunotherapy benefits. This article provides an update on the major developments in research related to predictive factors of immunotherapy for gastric cancer. We used the search term "predictive factors, immunotherapy, gastric cancer" to find the most current publications in the PubMed database related to predictive factors of immunotherapy in gastric cancer. Programmed cell death, genetic, and immunological factors are the main study topics of immunotherapy's predictive factors in gastric cancer. Other preventive factors for immunotherapy in gastric cancer were also found, including clinical factors, tumor microenvironment factors, imaging factors, and extracellular factors. Since there is currently no effective treatment for gastric cancer, we strongly propose that these studies be prioritized.