The following narrative review embarks on a comprehensive exploration of the pivotal role played by the gut microbiome within the Diet-Microbiota-Immunity (DMI) tripartite, aiming to enhance anti-cancer immunotherapy efficacy. While revolutionizing cancer treatment, resistance to immunotherapy and immune-related adverse events (irAEs) remain challenges. The tumor microenvironment (TME), shaped by cancer cells, influences immunotherapy resistance. The gut microbiome, influenced by genetics, environment, diet, and interventions, emerges as a critical player in TME reshaping, thereby modulating immune responses and treatment outcomes. Dietary patterns like the Mediterranean diet, caloric restriction modifications, and specific nutritional components show promise in influencing the tumor microenvironment and gut microbiome for better treatment outcomes. Antibiotics, disrupting gut microbiota diversity, may compromise immunotherapy efficacy. This review emphasizes the need for tailored nutritional strategies to manipulate microbial communities, enhance immune regulation, and improve immunotherapy accessibility while minimizing side effects. Ongoing studies investigate the impact of dietary interventions on cancer immunotherapy, pointing towards promising developments in personalized cancer care. This narrative review synthesizes existing knowledge and charts a course for future investigations, presenting a holistic perspective on the dynamic interplay between dietary interventions, the gut microbiome, and cancer immunotherapy within the DMI tripartite.

Cellular immunotherapy has recently emerged as a fourth pillar in cancer treatment co-joining surgery, chemotherapy and radiotherapy. Where, the discovery of immune checkpoint blockage or inhibition (ICB/ICI), anti-PD-1/PD-L1 and anti-CTLA4-based, therapy has revolutionized the class of cancer treatment at a different level. However, still some cancer patient escape this immune surveillance mechanism and become resistant to ICB-therapy. Therefore, a more advanced or an alternative treatment is required instantly. Despite the functional importance of epitranscriptomics in diverse clinico-biological practices, its role in improving the efficacy of ICB therapeutics has been limited. Consequently, our study encapsulates the evidences, as a possible strategy, to improve the efficacy of ICB-therapy by co-targeting molecular checkpoints especially N6A-modification machineries which could be reformed into RNA modifying drugs (RMD). Here, we have explained the mechanism of individual RNA-modifiers (editor/writer, eraser/remover and effector/reader) in overcoming the issues associated with high-dose antibody toxicities and drug-resistance. Moreover, we have shed light on the importance of suppressor of cytokine signalling (SOCS/CISH) and microRNAs in improving the efficacy of ICB-therapy, with brief insight on the current monoclonal antibodies undergoing clinical trials or already approved against several solid tumor and metastatic cancers. We anticipate our investigation will encourage researchers and clinicians to further strengthen the efficacy of ICB-therapeutics by considering the importance of epitranscriptomics as a personalized medicine.

Gastric cancer is a heterogeneous group of diseases with only a fraction of patients responds to immunotherapy. The relationships between tumor DNA damage response, the immune system and immunotherapy have recently attracted attention. Accumulating evidence indicate that DNA repair landscape is a significant factor in driving response to immune checkpoint blockade (ICB) therapy. In this study, to explore new prognostic and predictive biomarkers for gastric cancer patients who are sensitive and responsible to immunotherapy, we developed a novel 15-DNA repair gene signature (DRGS) and its related scoring system and evaluated the efficiency of DRGS in discriminating different molecular and immune characteristics and therapeutic outcomes of gastric adenocarcinoma. The results showed that DRGS high score patients showed significantly better therapeutic outcomes compared to DRGS low score patients (P < 0.001). Integrated analysis of multi-omics data demonstrated that the patients with high DRGS score were characteristic of high levels of anti-tumor lymphocytes infiltration, tumor mutation burden (TMB) and PD-L1 expression, and these patients exhibited a longer overall survival and may benefit more from ICB therapy, as compared to the low-score patients. Therefore, the DRGS and its scoring system may have implications in tailoring immunotherapy in gastric cancers.