The literature employed in this study was obtained from the Web of Science Core Collection (WoSCC) on 17 February 2025. Sources included the Science Citation Index-Expanded (SCI-E), the Social Sciences Citation Index (SSCI) and the Emerging Sources Citation Index (ESCI). We employed the following search strategies: (TS= (“Glioma*” OR “Glial Cell Tumor*” OR “Glioblastoma*” OR “Neuroglioma*” OR “Neurospongioma*” OR “Astrocytoma*” OR “Astroglioma*” OR “Gliosarcoma*”)) AND TS= (“Dendritic Cell*” OR “Dendrite Cell*” OR “Dendritic* Cell*” OR “Dendrocyte”). This approach yielded a total of 1875 records. We refined our selection to include only articles and review papers written in English, excluding records from 2025 to streamline the data processing. The final dataset included 1576 records spanning 1992 to 2024. Of these, articles (1,107) made up 70.24% of the total, while reviews (469) accounted for 29.76% ( Figure 1 ).

For the data analysis, we employed Microsoft Excel 2019, VOSviewer 1.6.19.0 and CiteSpace 6.4.R2 to conduct a visual analysis. A variety of metrics were examined, including the number of annual publications, the H-indexes of countries and authors and the number of co-citations. VOSviewer and CiteSpace were employed to create visual representations of the distribution of countries and regions, authors, co-cited authors, institutions, journals, co-cited journals, references and keywords. Subsequently, the keywords and co-cited references were analyzed for clustering and burst detection. The clustering labels were generated using the three algorithms available in Citespace software, namely log-likelihood ratio (LLR), latent semantic indexing (LSI) and mutual information(MI) (12).

A total of 1,576 articles were included in this analysis. The total number of non-self-cited citations across these articles was 57,232, with an average of 42.84 citations per article. The H-index for all articles was 118. Figures 2A, B delineated the annual publication count and annual citation count for articles related to dendritic cells in glioma.

As depicted in Figure 2 , the inaugural research article in this field was published in 1992. The period from 1992 to 1998 marked the beginning of research on DCs in glioma, with a relatively low volume of publications. The development phase from 1998 to 2016 was characterized by a steady increase in annual publications. The explosion phase from 2016 to 2024 witnessed a substantial surge in publications on dendritic cells in glioma, accounting for 58.06% of the total publications. This trend reflects the escalating interest among researchers in the potential role of dendritic cells in glioma research.

Between 1992 and 2024, research articles on dendritic cells in glioma were published from 59 different countries/regions, as shown in Figures 3A, B , and detailed in Table 1 . The United States (USA) had the largest number of publications (667/42.32%), followed by China (410/26.02%) and Germany (148/9.4%). The USA also led in citation count, amassing 38,144 citations, with China (9,709) and Germany (6,867) trailing behind. Figures 3C, D highlight the USA and China as dominant contributors. The node colors and line thickness in the figures denote the intensity of collaboration between countries, revealing strong collaborations between the USA and China, the USA and Japan, and the USA and Germany. The H-index, a novel method for assessing academic contributions, was also statistically analyzed. As shown in Figures 3E, F , the USA had the highest H-index (99), followed by China (51) and Germany (49). Taken together, these indices suggest that the USA holds a leading position in this field of research.

A network analysis of institutional co-occurrence was conducted using CiteSpace ( Figure 5 ) to identify organizations or institutions at the forefront of dendritic cell research in glioma. The top ten institutions, ranked by the number of publications and their centrality, are listed in Table 4 . The nodes in the figure symbolize institutions, with larger nodes denoting a greater number of publications from that institution. The links between nodes illustrate inter-institutional cooperation, with the colour of the links denoting the initiation of partnerships, and the thickness of the lines representing the intensity of the collaboration. The University of California System leads with 108 publications, followed by Duke University (62 publications) and Harvard University (56 publications). A purple circle around a node signifies a high degree of centrality (≥0.10), suggesting the institution is well-positioned to make transformative discoveries and serve as a bridge in the network. The institutions with the highest centrality are Institut National de la Sante et de la Recherche Medicale (Inserm) (0.23), NIH National Cancer Institute (NCI) (0.14), University of California System (0.13), the Helmholtz Association (0.13), and University of Texas System (0.11). The figure illustrates strong cooperation between these institutions.

The analysis of the source literature revealed that the journal with the highest number of publications in this field was Journal of Neuro-Oncology with 54 publications. These were closely followed by Frontiers in Immunology and Cancer Immunology Immunotherapy, with 53 and 51 publications, respectively ( Figure 6A ). The Journal Citation Reports (JCR) rankings of the top 10 journals with the highest publication counts were almost in the first (Q1) or second quartile (Q2), demonstrating the reliability of the publications included in this study. This suggests that these journals could be prioritized by researchers for future submissions.

Figure 6B presents the co-citation analysis of journals, with Cancer Research leading the list at 1,227 citations. Clinical Cancer Research and Journal of Immunotherapy followed with 1,111 and 1026 citations, respectively. Among the top 10 most-cited journals, Nature Medicine had the highest Impact Factor (IF) of 58.7 (2024). Notably, 80% of these top-cited journals were classified as Q1, with the remaining 20% falling into the Q2 category ( Table 5 ). Cancer Research emerged as the journal with the highest centrality (0.23), followed by Journal of Experimental Medicine (0.20) and Neurosurgery (0.19), highlighting the influential role these journals play in the field ( Table 5 ).

The dual map overlay in CiteSpace provides insights into the evolution of research across various disciplines ( Figure 6C ). The left side displays citing articles, while the right side shows cited articles. The coloured, curved path in the centre represents citation relationships. The yellow citation path indicates that research published in journals within the Molecular/Biology/Genetics categories are frequently cited by Molecular/Biology/Immunology journals. Furthermore, peripheral disciplines such as Physics/Materials/Chemistry, Ecology/Earth/Marine, Veterinary/Animal/Science, Environmental/Toxicology/Nutrition, and Psychology/Education/Social are also engaged in dendritic cell research in glioma. This underscores the multidisciplinary and collaborative nature of research in this field.

Co-cited references illustrate the level of interconnection between different sources. Utilizing VOSviewer, we identified the top five references with the highest co-citation frequencies ( Figures 7A, B , Table 6 ). Notably, the most frequently co-cited article was authored by Stupp, R., which demonstrated the significant survival benefit of introducing temozolomide early in radiotherapy for glioblastoma treatment (1). However, the quest to further enhance clinical outcomes remains an ongoing challenge (13). To further analyze the co-cited references, we employed CiteSpace with the following parameters: time slicing (1992–2024), years per slice (1), node type (cited reference), selection criteria (k=15), and pruning (Pathfinder, Pruning sliced networks&Pruning the merged network). As depicted in Figure 7C , this analysis generated a co-occurrence network comprising 1,139 nodes, 2,748 connections, and a density of 0.0042. Subsequently, we conducted a cluster analysis on the cited references using the LSI, yielding 97 clusters. The top 14 clusters are displayed in Figures 7D, E . Among these, the clustering modularity Q was 0.8028, and the average silhouette score S was 0.9078, suggesting a well-structured clustering with a significant cohesion. The value of the cluster number signifies the level of interest in the cluster topic within the discipline, with a smaller cluster value indicating higher attention. These clusters can be categorized into 4 main areas ( Figure 7E ). Firstly, research background and context, including (#1 current state, #2 brain cancer, #3 human glioma, #4 malignant glioma). Secondly, therapeutic strategies and approaches, including (#5 irradiated tumor cell vaccine, #7 adjuvant ifn-gamma treatment, #8 tk gene therapy, #14 cell therapy). Followed by immune responses and mechanisms, including (#12 responsive T-cell, #15 following depletion, #16 large glioma model), and finally, analysis and synthesis, including (#0 systematic review, #18 pan-cancer analysis).

Burst detection of cited references signifies a shift in research focus within a field. In CiteSpace, we set the parameters minimum Duration=2, g=1, and identified 25 references with significant citation bursts, underscoring their relevance in the field of dendritic cells in glioma ( Figure 7F ). Among these, seven papers published between 2017 and 2021 primarily focus on GBM, except for the 2021 article titled “The 2021 WHO classification of tumours of the central nervous system a summary” This article provides an updated overview of the classification system for CNS tumours, including GBM (14). The remaining articles concentrate on GBM treatment, predominantly through randomized, double-blind, controlled trials. They report on the results of clinical trials and explore immunotherapy in the treatment of GBM. For example, O’Rourke DM et al.(2017) shared initial experiences with chimeric antigen receptor (CAR) T cells in recurrent GBM, suggesting that although intravenous infusion exhibits on-target activity in the brain, enhancing the efficacy of EGFRvIII-directed strategies may require addressing the antigen heterogeneity and adaptive changes in the local tumour microenvironment (15). In another 2017 study, Michael Weller’s team conducted a Phase III clinical trial examining a vaccine called Rindopepimut (also known as CDX-110) that targets EGFRvIII, a mutated form of the epidermal growth factor receptor (EGFR). The findings indicate that diverse approaches could enhance the effectiveness of immunotherapy for GBM (16). A 2018 article corrects the initial survival results of a Phase III clinical trial using an autologous DC vaccine in newly diagnosed GBM patients, indicating that the addition of DCVax-L to standard therapy is feasible and safe in glioblastoma patients and may extend survival (17). In a 2019 article, Wen PY et al. reported that progression-free survival (PFS) significantly improved in patients treated with ICT-107, maintaining quality of life (QoL), particularly in the HLA-A2 subgroup, which showed elevated ICT-107 activity both in clinical and immunological outcomes (18). Another 2019 study explored neoadjuvant anti-PD-1 immunotherapy for recurrent GBM, suggesting that neoadjuvant therapy with PD-1 blockade enhances local and systemic anti-tumour immune responses, potentially offering a more effective treatment for this aggressive brain tumour (19). The 2020 article presents the findings from the CheckMate 143 phase III trial, comparing nivolumab and bevacizumab in patients with recurrent GBM. Although the primary endpoint was not reached, median overall survival (mOS) was similar between the nivolumab and bevacizumab treatment groups in patients with recurrent glioblastoma. The safety profile of nivolumab in glioblastoma patients was comparable to that previously observed in patients with other tumours (20).

A keyword co-occurrence network can facilitate the identification of research hotspots and trends within a specific field. In this study, we utilized VOSviewer software for keyword analysis, setting the minimum occurrence of a keyword to five, which yielded a total of 490 keywords ( Figure 8A , Table 7 ). Subsequent cluster analysis revealed nine distinct clusters ( Figures 8B, C ), encompassing seven research directions and areas of study. The largest cluster is the cluster 1 (red), with 105 keywords, including immunotherapy, glioblastoma, t cell, glioblastoma multiforme, temozolomide, clinical trial, radiation-therapy, dendritic cell vaccination, newly diagnosed glioblastoma, phase-ii trial, etc. Cluster 2 (green) includes 102 keywords, such as dendritic cell, malignant glioma, central nervous system, brain tumor, vaccination, antitumor immunity, cytotoxic t lymphocyte, antigen, in-vitro, cancer immunotherapy, etc. Cluster 3 (blue) also has 92 keywords, mainly including glioma, cancer, expression, survival, tumor, tumor microenvironment, activation, cell, receptor, identification, etc. Cluster 4 (yellow) contains 82 keywords, focusing on regulatory t cell, macrophage, blood brain barrier, immune suppression, suppressor-cells, cancer stem cell, natural-killer-cells, tumor-associated macrophages, microglia, differentiation. Cluster 5 (purple) has 51 keywords, mainly related to vaccine, therapy, apoptotic cells, melanoma, delivery, mechanism, nanoparticles, trial, drug delivery, cross-presentation. Cluster 6 (light blue), with 37 keywords, primarily features responses, inhibition, plasmacytoid dendritic cells, efficacy, indoleamine 2,3-dioxygenase, immune escape, ligand, cutting edge, aryl-hydrocarbon receptor, innate. Cluster 1 and 5 mainly reflect glioblastoma immunotherapy and clinical trials, while Cluster 2 and 6 mainly emphasize dendritic cells and antitumor immunity. Cluster 3 and 4 mainly reflect tumor microenvironment and immune regulation. In addition, we utilized CiteSpace to visualize the keyword co-occurrence network, generating a map with 336 nodes, 1664 connections and a density of 0.0296 ( Figure 8D ). Burst detection analysis identified that recent studies on ‘double blind’, ‘immune infiltration’, ‘cell’, and ‘tumour microenvironment’ are the most current keywords ( Figure 8E ), signifying these areas as recent research hotspots and potential future research focuses.

This investigation analyzed 1,576 articles on dendritic cells in glioma retrieved from the Web of Science core database, using VOSviewer, CiteSpace and Excel. Over the past 33 years, the publication of papers in this field has generally trended upwards, with the annual average co-citations similarly increasing. Prior to 1998, this area of study was relatively unexplored. However, after 1998, research on the role of dendritic cells in glioma gained increasing attention, particularly from 2016 onwards, when the field began to reach a stage of relative maturity. A total of 1,576 articles were included, revealing a significant annual increase in dendritic cell-focused glioma research. The USA, China, and Germany led in publication output. Okada, Hideho had the most publications, while Stupp, R had the highest co-citations. Journal of Neuro-Oncology published the most articles, and Cancer Research received the highest citations. The analysis highlights key themes such as “dendritic cell”, “immunotherapy”, and “glioblastoma”, and emerging interests like “tumor microenvironment”, “immune infiltration”, and “double blind”. Details are as follows:

Currently, the USA, China and Germany are the leading nations conducting research on dendritic cells in glioma ( Figure 3 ). Among them, the USA stands out with the highest number of publications, citations, H-index and TLS with an average citation rate of 57.19, indicating its dominance in both quantity and quality. Despite China ranks second in terms of published articles, its average citation of 23.68 suggests there is room for improvement in producing high-quality papers. Furthermore, five of the top 10 institutions by centrality are based in the USA, underscoring its pivotal role in the global collaboration network ( Table 4 ). Figure 3C, D reveal particularly strong cooperative relationships between the USA and China, the USA and Japan, as well as the USA and Germany. The strength of connections between nodes indicates that enhanced international cooperation could further accelerate progress in this area.

In terms of authorship, Okada, Hideho leads in both publications and contributions to dendritic cell-based immunotherapy for glioma. His phase I/II clinical trial on a poly-ICLC-boosted αDC1-based vaccine for patients with recurrent malignant glioma showed promising safety, immunogenicity, and preliminary clinical activity. Notably, Okada, Hideho is among the top 10 co-cited authors, with a centrality value exceeding 0.1, further demonstrating his significant position in the research field of dendritic cells and glioma (21). R. Stupp, the most frequently co-cited researcher, is an authority in Neuro-Oncology. His research interests encompass primary and secondary brain tumors, head and neck cancers, drug discovery, chemotherapy and radiation therapy. Stupp and his team have shown that Tumor Treating Fields improve survival rates in patients with glioblastoma (22). John H. Sampson also boasts a strong publication and co-citation record, particularly for his team’s development of Cytomegalovirus (CMV) pp65 DC vaccines, which have shown consistent efficacy in three consecutive clinical trials for glioblastoma (23).