Introduction Conventional cancer therapies remain limited by systemic toxicity, drug resistance, poor tumor-site bioavailability, and immunosuppressive signaling within the tumor microenvironment (TME). Exosomes have therefore gained attention as mediators of tumor-cell communication and as potential tools for diagnosis and therapy. Methods This systematic review synthesized peer-reviewed studies published from 2021 to 2025. The review followed PRISMA 2020 principles and focused on exosome-mediated signaling, tumor progression, immune modulation, therapeutic delivery, and liquid-biopsy applications in oncology. Results The included studies showed that tumor-derived exosomes support angiogenesis, pre-metastatic niche formation, immune evasion, and therapy resistance by transferring bioactive cargo such as PD-L1, TGF-beta, non-coding RNAs, and pro-angiogenic molecules. Exosomes also showed potential as drug-delivery nanocarriers, gene-transfer platforms, cancer-vaccine components, and non-invasive biomarkers for diagnosis, prognosis, and treatment monitoring. Conclusion Exosome-based approaches offer relevant opportunities for precision oncology. Their clinical translation remains limited by heterogeneous cargo composition, non-standardized isolation methods, uncertain dosing, large-scale manufacturing constraints, and incomplete pharmacokinetic evaluation.
Wiliem Souhaly J, Stefani Cleorata Tamelan C, Noya A et al. Exosome-Mediated Communication in The Tumor Microenvironment: Mechanism and Therapeutic Challenges [version 1; peer review: awaiting peer review]. F1000Research 2026, 15:1314 (https://doi.org/10.12688/f1000research.186333.1)
Systematic Review
[version 1; peer review: awaiting peer review]
https://orcid.org/0000-0002-4310-0226
1, Christine Stefani Cleorata Tamelan2, Anjela Noya3, [...] Yunita Messe1, Roynerd Vhiranda Katanga Takandjandjihttps://orcid.org/0009-0000-2336-2248
2, Fitri Lestari2, Novelia Gabrieli B. So'o3, Jekli Jekli2, Rafael Tirta Bayu Andika4,5, Petra Cendana Putra Mauboi1, Diana Yasintha Marini2, Khintan Maulin Paquita2, Indah Nian Mailopuw4https://orcid.org/0000-0002-4310-0226
1, Christine Stefani Cleorata Tamelan2, [...] Anjela Noya3, Yunita Messe1, Roynerd Vhiranda Katanga Takandjandjihttps://orcid.org/0009-0000-2336-2248
2, Fitri Lestari2, Novelia Gabrieli B. So'o3, Jekli Jekli2, Rafael Tirta Bayu Andika4,5, Petra Cendana Putra Mauboi1, Diana Yasintha Marini2, Khintan Maulin Paquita2, Indah Nian Mailopuw41 Biology, Gadjah Mada University Faculty of Biology, Yogyakarta, Special Region of Yogyakarta, Indonesia
2 Biomedical Science, Gadjah Mada University, Yogyakarta, Special Region of Yogyakarta, Indonesia
3 Tropical Medicine, Gadjah Mada University, Yogyakarta, Special Region of Yogyakarta, Indonesia
4 Biotechnology, Gadjah Mada University Graduate School, Yogyakarta, Special Region of Yogyakarta, Indonesia
5 School of Life Sciences, University of Dundee School of Life Sciences, Dundee, Scotland, UK
Jantje Wiliem Souhaly
Roles: Conceptualization, Data Curation, Formal Analysis, Funding Acquisition, Investigation, Methodology, Project Administration, Supervision, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Christine Stefani Cleorata Tamelan
Roles: Conceptualization, Funding Acquisition, Methodology, Writing – Original Draft Preparation, Writing – Review & Editing
Anjela Noya
Roles: Conceptualization, Funding Acquisition, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Yunita Messe
Roles: Conceptualization, Data Curation, Funding Acquisition, Investigation, Project Administration, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing
Roynerd Vhiranda Katanga Takandjandji
Roles: Funding Acquisition, Methodology, Writing – Review & Editing
Fitri Lestari
Roles: Funding Acquisition, Methodology, Writing – Review & Editing
Novelia Gabrieli B. So'o
Roles: Funding Acquisition, Validation, Writing – Original Draft Preparation, Writing – Review & Editing
Jekli Jekli
Roles: Funding Acquisition, Methodology, Writing – Review & Editing
Rafael Tirta Bayu Andika
Roles: Formal Analysis, Funding Acquisition, Writing – Review & Editing
Petra Cendana Putra Mauboi
Roles: Data Curation, Funding Acquisition, Investigation, Writing – Review & Editing
Diana Yasintha Marini
Roles: Funding Acquisition, Methodology, Writing – Review & Editing
Khintan Maulin Paquita
Roles: Funding Acquisition, Methodology, Writing – Review & Editing
Indah Nian Mailopuw
Roles: Formal Analysis, Funding Acquisition, Writing – Review & Editing
OPEN PEER REVIEW
REVIEWER STATUS AWAITING PEER REVIEW
Conventional cancer therapies remain limited by systemic toxicity, drug resistance, poor tumor-site bioavailability, and immunosuppressive signaling within the tumor microenvironment (TME). Exosomes have therefore gained attention as mediators of tumor-cell communication and as potential tools for diagnosis and therapy.
MethodsThis systematic review synthesized peer-reviewed studies published from 2021 to 2025. The review followed PRISMA 2020 principles and focused on exosome-mediated signaling, tumor progression, immune modulation, therapeutic delivery, and liquid-biopsy applications in oncology.
ResultsThe included studies showed that tumor-derived exosomes support angiogenesis, pre-metastatic niche formation, immune evasion, and therapy resistance by transferring bioactive cargo such as PD-L1, TGF-beta, non-coding RNAs, and pro-angiogenic molecules. Exosomes also showed potential as drug-delivery nanocarriers, gene-transfer platforms, cancer-vaccine components, and non-invasive biomarkers for diagnosis, prognosis, and treatment monitoring.
ConclusionExosome-based approaches offer relevant opportunities for precision oncology. Their clinical translation remains limited by heterogeneous cargo composition, non-standardized isolation methods, uncertain dosing, large-scale manufacturing constraints, and incomplete pharmacokinetic evaluation.
Exosomes, Tumor Microenvironment, Molecular Signaling, Targeted Drug Delivery, Systematic Review
Corresponding author: Jantje Wiliem Souhaly Competing interests: No competing interests were disclosed.
Grant information: This systematic review was supported by the Indonesia Endowment Fund for Education (Lembaga Pengelola Dana Pendidikan / LPDP), Ministry of Finance of the Republic of Indonesia, through scholarships awarded to the authors.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Copyright: © 2026 Wiliem Souhaly J et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. How to cite: Wiliem Souhaly J, Stefani Cleorata Tamelan C, Noya A et al. Exosome-Mediated Communication in The Tumor Microenvironment: Mechanism and Therapeutic Challenges [version 1; peer review: awaiting peer review]. F1000Research 2026, 15:1314 (https://doi.org/10.12688/f1000research.186333.1) First published: 06 Aug 2026, 15:1314 (https://doi.org/10.12688/f1000research.186333.1) Latest published: 06 Aug 2026, 15:1314 (https://doi.org/10.12688/f1000research.186333.1)
Conventional cancer therapies, including chemotherapy, radiotherapy, and targeted therapy, have improved survival in many tumor types. Even so, their clinical benefit remains constrained by toxicity, drug resistance, and limited delivery to malignant tissue. Cytotoxic chemotherapy illustrates this problem clearly. These agents target rapidly dividing cells and therefore damage normal tissues such as bone marrow, gastrointestinal epithelium, and hair follicles. Dose-dependent adverse effects can reduce treatment intensity, delay subsequent cycles, or force treatment discontinuation. Radiotherapy provides better spatial control, but it can still injure adjacent normal tissues and produce acute or late complications (Yan et al., 2024; Zafar et al., 2025).
Therapeutic resistance also limits durable remission. Resistance can be intrinsic or acquired during treatment. Cancer cells may evade therapy through drug-efflux transporters such as P-glycoprotein/MDR1, altered drug metabolism, enhanced DNA repair, and impaired programmed cell death. Once these mechanisms emerge, recurrent tumors often show a more aggressive and multidrug-resistant phenotype, which narrows later treatment options (Álvarez-Carrasco et al., 2025).
Drug exposure at the tumor site is another unresolved barrier. Many conventional and targeted agents show suboptimal pharmacokinetic behavior, poor tissue penetration, or inadequate bioavailability in the tumor core. The TME adds further resistance through high interstitial pressure, dense extracellular matrix, hypoxia, abnormal vasculature, and immunosuppressive signaling. These features can restrict therapeutic access and reduce drug activity, especially for large molecules and complex biologics (Huang et al., 2021).
Extracellular vesicles (EVs) have become important in this context because they mediate communication between tumor cells and surrounding stromal, endothelial, and immune cells. Exosomes represent a major small-EV subtype. Their biogenesis begins with inward budding of the plasma membrane and formation of early endosomes, followed by maturation into late endosomes. Additional inward budding of the endosomal limiting membrane generates intraluminal vesicles within multivesicular bodies. These bodies either fuse with lysosomes for degradation or fuse with the plasma membrane, releasing intraluminal vesicles as exosomes (Liu et al., 2021a; Yu et al., 2024).
Exosomes are enclosed by a lipid bilayer and carry molecular cargo that reflects the state of the parent cell. Their contents include proteins, lipids, mRNAs, microRNAs, long non-coding RNAs, transfer RNAs, mitochondrial DNA, and double-stranded DNA. Surface proteins such as CD9, CD63, CD81, adhesion molecules, and MHC class I and II molecules contribute to cell recognition and targeting. Other proteins, including TSG101 and HSP70, relate to vesicle formation and membrane trafficking (Hánělová et al., 2024; Palomar-Alonso et al., 2023).
The exosomal membrane contains cholesterol, ceramides, and other lipids that protect internal cargo from enzymatic degradation. This stability allows exosomes to act as carriers for local and long-range signaling. Recipient cells internalize exosomes through endocytosis, membrane fusion, or ligand-receptor binding. In cancer, tumor-derived exosomes (TDEs) use these routes to transfer immunosuppressive, pro-angiogenic, metastatic, and resistance-associated signals (Palomar-Alonso et al., 2023; Whiteside, 2016).
TDEs can suppress antitumor immunity by carrying or inducing molecules such as PD-L1 and TGF-beta. They can impair T-cell and natural killer-cell activity and promote pro-tumor immune phenotypes, including M2-like macrophage polarization. They also deliver pro-angiogenic mediators such as VEGF and selected microRNAs to endothelial cells. Beyond the primary tumor, TDEs remodel extracellular matrix, recruit bone-marrow-derived cells, and create pre-metastatic niches that favor tumor-cell survival at distant sites. Resistant tumor cells may also use exosomes to transfer resistance-associated proteins and RNAs to drug-sensitive cells (Yang et al., 2021).
These biological properties have encouraged research on exosomes as therapeutic vehicles and therapeutic targets. Compared with many synthetic nanoparticles, exosomes offer biocompatibility, low immunogenicity, membrane stability, and natural cell-interaction capacity. Their lipid bilayer can protect siRNAs, microRNAs, proteins, and small molecules during circulation. Their surface molecules can also support tumor targeting, and bioengineering can further enhance this specificity through peptides, antibodies, or nanobodies (Boukouris & Mathivanan, 2015; Serrano et al., 2025; Zhang et al., 2025).
Exosomes can also cross biological barriers that limit many drugs, including the blood-brain barrier, which makes them relevant for malignancies such as glioma (Khatami et al., 2023). At the same time, TDEs remain important therapeutic targets because they contribute to metastasis, immune evasion, and resistance. Blocking exosome-mediated transfer of P-glycoprotein, resistance-associated microRNAs, or PD-L1-positive vesicles may help restore drug sensitivity and antitumor immunity (Kato et al., 2015; Vautrot et al., 2021).
Despite this promise, exosome-based oncology remains difficult to translate. Isolation methods, vesicle characterization, product purity, cargo heterogeneity, dosing, large-scale manufacturing, and regulatory requirements remain unresolved. This systematic review synthesizes evidence from 2021 to 2025 on exosome-mediated communication in the TME, evaluates diagnostic and therapeutic applications, and identifies barriers that currently restrict clinical implementation.
This systematic literature review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 (PRISMA 2020) framework. A literature search was conducted in PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar. The search covered peer-reviewed publications on exosomes in cancer development, diagnosis, and treatment from January 2021 to December 2025. The final search was conducted on February 19, 2026.
The search combined controlled vocabulary and free-text terms related to exosomes, extracellular vesicles, cancer, the tumor microenvironment, therapy, and liquid biopsy. The core search string was: (“exosomes” OR “extracellular vesicles” OR “tumor-derived exosomes”) AND (“cancer” OR “neoplasm” OR “tumor microenvironment”) AND (“drug delivery” OR “immunotherapy” OR “gene therapy” OR “liquid biopsy”). The syntax was adapted for each database. For Google Scholar, only the first 200 records sorted by relevance were screened to maintain feasibility and reduce retrieval of weakly related records.
Studies were eligible when they met all of the following criteria: (1) full-text peer-reviewed articles published in English between 2021 and 2025; (2) studies examining the molecular mechanisms or translational relevance of exosomes in cancer; and (3) studies reporting mechanistic, diagnostic, or therapeutic findings relevant to the review objectives. Eligible domains included tumor-microenvironment regulation, metastasis, angiogenesis, immune evasion, drug delivery, immunotherapy, gene therapy, and liquid biopsy.
Studies were excluded when they focused on non-cancer conditions or plant-derived exosomes without clear relevance to human oncology; when they were conference abstracts, editorials, letters, commentaries, or unverified preprints; when they lacked sufficient mechanistic or clinical relevance; or when their findings were already reported in more comprehensive publications.
All search results were imported into Zotero, merged, and deduplicated. After record management, titles and abstracts were screened against the eligibility criteria. Full-text articles were then reviewed for relevance to the review questions. The primary screening was conducted by one reviewer. To strengthen conceptual consistency, three subject-matter experts in exosome biology, immunology, and cancer research reviewed the screening framework, thematic categorization, and interpretation of the included studies. Disagreements about eligibility or categorization were resolved through discussion.
Data were extracted using a structured template. Extracted variables included first author, year of publication, study design, cancer type or model, main molecular mechanisms, key findings, and diagnostic or therapeutic relevance. The evidence was synthesized narratively because the included studies differed substantially in design, cancer type, exosome source, isolation method, cargo type, and outcome measures. The quality and risk of bias of the included studies were assessed through a collaborative review by all authors, rather than using structured checklist tools.
The database search identified 10,664 records: 10,401 from PubMed, 63 from the Cochrane Library, and 200 from Google Scholar. During record management, 536 duplicate records were removed before screening. A total of 10,128 records were screened by title and abstract. Of these, 9,800 records were excluded because they did not match the scope of the review. The remaining 328 reports were retrieved and assessed in full. After full-text review, 296 reports were excluded because they contained redundant or overlapping data, lacked adequate molecular or mechanistic depth, or fell outside the predefined review scope. The final qualitative synthesis included 32 studies. The PRISMA flow diagram summarizes the selection process ( Figure 1). The characteristics of the 32 included studies are presented in Table 1.
Exosomes in tumor growth and angiogenesis
TDEs contribute to tumor growth by changing the behavior of surrounding stromal and endothelial cells. The included studies showed that TDEs transfer oncogenic proteins, lipids, and nucleic acids to recipient cells. This transfer can weaken tumor-suppressive pathways, strengthen proliferative signaling, and support malignant-cell survival. Exosome-associated non-coding RNAs were repeatedly linked to signaling programs that help tumor cells adapt to the TME (Liu et al., 2021a; Stefanius et al., 2021; Xu et al., 2022).
TDEs also support epithelial-to-mesenchymal transition (EMT), which increases cell motility, invasiveness, and metastatic potential. Exosomal cargo can alter intracellular signaling and cytoskeletal organization in recipient cells, shifting them toward a migratory phenotype. TDEs also influence fibroblasts and macrophages. These cells may then secrete growth factors, cytokines, and matrix-remodeling enzymes that help maintain a pro-tumor microenvironment (Hao et al., 2022; Liu et al., 2021a; Stefanius et al., 2021; Xu et al., 2022).
Angiogenesis is another major process shaped by TDEs. Solid tumors require new blood vessels to expand beyond a limited size. TDEs can stimulate endothelial proliferation, migration, and tube formation by transferring pro-angiogenic mediators and regulatory RNAs. In glioblastoma, (Z. Wang et al., 2021) reported that exosome-mediated activation of the Hippo-TAZ/VEGF-C axis promoted angiogenic responses. These findings position TDEs as active regulators of vascular remodeling rather than passive by-products of malignant cells (Liu et al., 2021a; Stefanius et al., 2021; Z. Wang et al., 2021).
Exosomes in metastasis and pre-metastatic niche formation
Metastasis remains the main cause of cancer-related death. TDEs participate in this process before disseminated tumor cells arrive at distant tissues. They carry protected molecular cargo through blood and lymphatic fluids and can prepare specific organs for future tumor-cell colonization. This process, known as pre-metastatic niche formation, is one of the most important systemic functions of TDEs in cancer progression (Bai et al., 2022).
Exosomal biodistribution appears to be influenced by surface proteins, including integrins, which may contribute to organotropism. Several studies suggest that exosome-associated molecular signatures help define where metastatic spread is likely to occur. In this way, TDEs can condition distant tissues before the physical arrival of tumor cells (Zhao et al., 2021).
At target organs, TDEs can remodel the local microenvironment through extracellular-matrix reorganization, inflammatory signaling, and fibrotic change. These alterations favor tumor-cell adhesion, survival, and outgrowth. (G. Zhu et al., 2021) reported that hypoxia-associated small extracellular vesicles enriched in LOXL2 supported pre-metastatic niche formation in head and neck cancer and correlated with poor clinical outcome. The available evidence therefore supports a direct role for TDEs in metastatic organ conditioning.
Modulation of the tumor microenvironment and immune evasion
The TME often suppresses antitumor immunity, and TDEs help maintain this state. They can impair cytotoxic T lymphocytes, natural killer cells, and other immune effector cells that normally participate in tumor surveillance. PD-L1-associated signaling is one of the most frequently reported mechanisms. Exosomal PD-L1 or exosome-induced PD-L1 signaling can reduce T-cell activation and weaken antitumor function (Hao et al., 2022; B. Wang et al., 2024a).
TDEs also change immune-cell composition within tumors. They can promote macrophage polarization toward pro-tumor phenotypes and strengthen reciprocal signaling between tumor cells and tumor-associated macrophages. (B. Wang et al., 2024a) described mutual PD-L1-mediated immunosuppression between macrophages and tumor cells through exosome-dependent communication. This finding shows that immune escape is not a one-directional process but a dynamic communication loop.
Non-immune stromal cells are also affected. TDEs can reprogram fibroblasts and related stromal compartments, increasing fibrosis, extracellular-matrix remodeling, and immune exclusion. These changes may restrict drug penetration and reinforce therapeutic resistance. Together, the evidence indicates that TDEs coordinate several layers of tumor-supportive communication in the TME (Hao et al., 2022; B. Wang et al., 2024a; Xu et al., 2022).
Exosomes as drug delivery vehicles
Natural exosome loading and delivery
Exosomes have attracted interest as drug-delivery vehicles because they combine membrane stability, biocompatibility, and natural cell-interaction capacity. The included studies examined both native and engineered exosomes as carriers for anticancer agents. Early approaches used exosomes derived from immune cells or mesenchymal stem cells, followed by drug or nucleic-acid loading. Efficient and controlled cargo encapsulation remains a major challenge. Small lipophilic drugs, including doxorubicin and paclitaxel, have often been loaded through passive incubation or similar methods. These strategies use the lipid bilayer and the physicochemical properties of the cargo to promote incorporation. Across experimental models, exosome-mediated delivery improved intracellular transport and, in some settings, produced stronger antitumor activity than free-drug administration (Kim et al., 2021; Moon & Chang, 2022). Active loading methods, including electroporation and related membrane-disruptive techniques, have been used to improve encapsulation of larger molecules such as proteins and siRNAs. Because exosomes naturally transfer genetic material between cells, they are suitable candidates for nucleic-acid delivery. Some studies also reported that exosomes derived from cells with tumor-homing capacity may retain partial tropism after loading. These effects were not uniform, indicating that donor-cell source, cargo type, and loading method strongly influence therapeutic performance (Kim et al., 2021; J. Wang et al., 2024b).
Engineered and targeted exosomes
Engineered exosomes offer greater control than native exosomes. Surface modification, cargo engineering, and donor-cell programming can improve tumor targeting, loading efficiency, and stability. These strategies were developed to overcome the inconsistent targeting and low production yield observed with natural exosome preparations (Kim et al., 2021; J. Wang et al., 2024b). Surface functionalization is one of the most developed strategies. Exosomal membranes can be engineered to display tumor-targeting ligands, antibodies, or nanobodies. Examples include anti-EGFRvIII exosomes in glioblastoma (Rahmani et al., 2023), anti-BCMA engineered exosomes in multiple myeloma (Yuan et al., 2024), and anti-HER2 nanobody-targeted exosomes in HER2-positive breast cancer models (Al-Khafaji et al., 2025), and anti-HER2 nanobody targeted exosomes in HER2 positive breast cancer models. These studies support the view that surface engineering can significantly improve therapeutic precision. Cargo engineering provides a second route to improve therapeutic value. Parent cells can be modified before vesicle production so that therapeutic molecules are incorporated into newly formed exosomes. Alternatively, isolated vesicles can be loaded exogenously with drugs or nucleic acids. These approaches shift exosomes from naturally secreted vesicles toward programmable nanocarriers for precision cancer therapy.
Exosomes in immunotherapy
Exosomes as cancer vaccines
Although TDEs are often associated with immunosuppressive functions, the included studies indicate that exosomes can also be engineered to stimulate antitumor immunity. This dual role has positioned exosomes as promising platforms for cancer vaccine development. The primary aim of exosome based cancer vaccines is to deliver tumor associated antigens (TAAs) to antigen presenting cells (APCs), especially dendritic cells (DCs), in order to initiate adaptive immune responses. Several included studies focused on dendritic cell derived exosomes (Dex), which retain key antigen presentation components such as major histocompatibility complex (MHC) molecules and co-stimulatory proteins. These properties make Dex attractive as cell free nanovaccines capable of activating tumor specific immune responses (Li et al., 2023; Xia et al., 2022; H. Zhu et al., 2022).
The included evidence further showed that Dex can transfer activating signals to APCs or directly to T cells, promoting cytotoxic T lymphocyte expansion and antitumor activity. In addition, antigen enriched or neoantigen loaded Dex platforms were investigated as personalized immunotherapeutic strategies. For example (H. Zhu et al., 2022) reported that MUC1 conjugated Dex vaccine, for example, was reported to induce both humoral and cellular immune responses and suppress tumor growth in vivo. Taken together, these findings support the feasibility of exosome based cancer vaccination.
Delivery of immunomodulatory agents
Exosomes can also deliver immunomodulatory cargo. Their membrane-protected transport and low immunogenicity make them attractive for localized immune modulation within the TME (Moon and Chang 2022; Wang J et al. 2024b). Included studies described exosomal delivery of cytokines, checkpoint-modulating molecules, and nucleic acids that alter immune signaling.
Pucci et al. (2021) showed that tumor-derived small extracellular vesicles regulated macrophage inflammatory programs and PD-L1 expression through IL-6/STAT3 and TLR4-related pathways. De Miguel-Perez et al. (2023) reported that extracellular-vesicle-associated TGF-beta predicted response to immune-checkpoint inhibitors and survival in non-small cell lung cancer. These findings show that exosome-associated immune signals are biologically relevant and may also hold biomarker value.
Engineered exosome immunotherapy is also progressing. Chen et al. (2025) generated dendritic-cell-derived extracellular vesicles expressing interleukin-12 and anti-CTLA-4 on their surface for combination immunotherapy. Such platforms may enhance local immune stimulation while limiting systemic toxicity. However, translation requires better control of biodistribution, potency, and immune-related adverse effects.
Exosomes for gene therapy
Exosomes are promising carriers for therapeutic nucleic acids because they naturally mediate horizontal transfer of genetic material. Among the reviewed applications, siRNA delivery was the most extensively studied. Engineered exosomes have been used to carry siRNAs targeting oncogenic and resistance-related pathways. Kalluri et al. (2025) provided translational support through a phase I study of exosomes carrying KRAS(G12D)-specific siRNA in pancreatic cancer. Soma et al. (2022) also showed that exosome-capturing antibody-siRNA complexes could enter multiple myeloma cells and suppress target transcripts.
Exosomes have also been examined as carriers or mediators of mRNAs, microRNAs, and long non-coding RNAs. Tang et al. (2021) described exosomal mRNAs and lncRNAs related to bortezomib resistance in multiple myeloma. Yao et al. (2024) showed that extracellular-vesicle-packaged lncRNA from cancer-associated fibroblasts promoted immune evasion by downregulating HLA-A in pancreatic cancer. These studies illustrate both sides of exosomal nucleic-acid transfer: it can drive tumor progression, but it can also be redirected for therapeutic delivery. Efficient loading, tissue-specific delivery, and off-target control remain central barriers to clinical use.
Liquid biopsy: exosomes as biomarkers
Exosomes have gained attention in cancer diagnostics because they can be isolated from accessible body fluids, including plasma, serum, urine, and saliva. TDEs preserve molecular features of the parent tumor cell, while their lipid membrane protects proteins, RNAs, and other cargo from degradation during circulation. This stability supports their use in liquid-biopsy platforms for screening, prognosis, and treatment monitoring (Yu W et al., 2021; Yu D et al., 2022).
Several included studies reported diagnostic value across different tumor types. In head and neck cancer, Hofmann et al. (2022) found that plasma- and saliva-derived exosomal miRNA profiles showed diagnostic potential. In neuroblastoma, Morini et al. (2023) identified plasma-derived exosome proteins as potential diagnostic and prognostic biomarkers. In colorectal cancer, Rizk et al. (2024) reported that serum exosomal lncRNA NAMPT-AS had diagnostic and prognostic relevance. Exosome biomarkers may also support longitudinal surveillance. Changes in exosomal cargo can reflect tumor progression, treatment response, residual disease, and clinical outcome. Their routine clinical use, however, depends on reproducible isolation methods, validated analytical platforms, standardized reporting, and stronger linkage between biomarker profiles and patient-level endpoints.
Current challenges in clinical translation
Clinical translation of exosome-based therapy remains constrained by manufacturing, analytical, pharmacological, and regulatory barriers. Primary cells often produce low vesicle yields, and existing culture systems are difficult to scale while preserving product quality and biological activity. Isolation and purification methods also vary widely. Ultracentrifugation, ultrafiltration, size-exclusion, immunoaffinity capture, and precipitation-based methods can produce vesicle populations with different purity, contaminant profiles, and biological effects.
Product characterization remains incomplete. Standard criteria for vesicle size, concentration, purity, surface markers, cargo composition, potency, and batch consistency are not yet uniform. Dosing also presents a conceptual problem. Exosome dose cannot be defined only by mass; it must also consider vesicle number, cargo content, source cell, route of administration, and biological activity. Biodistribution may vary by donor-cell origin and may be affected by clearance through the reticuloendothelial system.
Safety and regulatory uncertainty further complicate development. Allogeneic exosomes, engineered vesicles, and inadequately purified preparations may carry unwanted immune or biological effects. These issues require standardized quality-control frameworks, validated potency assays, pharmacokinetic data, and long-term safety monitoring before broader clinical implementation (Buschmann et al. 2021; Kim et al. 2021; St-Denis-Bissonnette et al. 2023; Wang J et al. 2024b).
Future directions and emerging strategies
Future progress will depend on improved exosome engineering and more rigorous translational workflows. Surface engineering, cargo optimization, and disease-specific targeting have already improved therapeutic precision in glioblastoma, multiple myeloma, breast cancer, and pancreatic cancer models (Rahmani et al. 2023; Yuan et al. 2024; Chen et al. 2025; Kalluri et al. 2025; Al-Khafaji et al. 2025). These studies suggest that exosomes are moving beyond proof-of-concept delivery systems toward more programmable therapeutic platforms.
Manufacturing innovation is equally important. Scalable production, standardized characterization, and clinically relevant biomanufacturing must be developed in parallel with mechanistic research. St-Denis-Bissonnette et al. (2023) described a large-scale workflow for producing natural killer cells and natural-killer-cell-derived extracellular vesicles for cancer immunotherapy. Such workflows provide practical models for future clinical translation.
In diagnostics, exosome research will likely move toward integrated liquid-biopsy platforms that combine vesicle isolation, cargo profiling, and clinical-risk modeling. The value of these platforms will depend on analytical reproducibility, external validation, and direct association with clinical endpoints. The field therefore needs stronger links between mechanism, manufacturing, biomarker validation, and trial design.
This review has several strengths. It used a predefined search strategy, applied PRISMA 2020 principles, and synthesized recent evidence from 2021 to 2025 across mechanistic, translational, therapeutic, and diagnostic domains. The review also organized the literature around clinically relevant themes, including immune evasion, angiogenesis, metastasis, drug delivery, gene therapy, vaccine development, liquid biopsy, and manufacturing barriers.
Several limitations should be considered. First, the included studies were highly heterogeneous in cancer type, exosome source, isolation method, cargo characterization, dosing strategy, and outcome measure. This heterogeneity prevented quantitative pooling and limited the ability to make standardized conclusions across models. Second, the review was restricted to English-language publications and selected databases, which may have introduced language and database-selection bias. Third, the first-stage screening was conducted by one reviewer, although expert review was used to strengthen thematic interpretation. Fourth, the Google Scholar search was limited to the first 200 relevance-ranked records, which may have missed some eligible studies. These limitations should be considered when interpreting the conclusions.
Exosomes are central mediators of intercellular communication in the TME. They influence cancer progression by regulating immune evasion, angiogenesis, metastasis, pre-metastatic niche formation, and therapy resistance. Their capacity to transfer protected molecular cargo also makes them attractive for targeted drug delivery, gene therapy, cancer vaccines, and liquid-biopsy diagnostics. Despite this potential, clinical translation remains limited by cargo heterogeneity, non-standardized isolation and characterization, uncertain dosing, manufacturing constraints, biosafety concerns, and regulatory complexity. Future work should prioritize standardized methods, reproducible biomarker validation, scalable production systems, and clinically relevant studies that connect exosome biology with patient outcomes.
The authors acknowledge that this manuscript was prepared using generative artificial intelligence (AI) and AI assisted technologies. Specifically, ChatGPT (version GPT-4o) was implemented to enhance the clarity of language and the flow of the structure, while QuillBot was implemented to refine grammar and paraphrase. The authors examined, revised, and verified the text after using these tools to ensure accuracy and academic integrity. All publication content is the authors’ responsibility.
Underlying data for this study are openly available in the Zenodo repository at https://doi.org/10.5281/zenodo.21298015 (Wiliem Souhaly et al., 2026) under the title Exosome-Mediated Communication in the Tumor Microenvironment: Mechanism and Therapeutic Challenges. The dataset contains the following underlying data: Zotero_Literature_Search_Results.csv (CSV file containing the comprehensive list of literature search results and metadata), the PRISMA_2020_Checklist.pdf and PRISMA_Flowchart.png. All data are distributed under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).
The authors gratefully acknowledge the Indonesia Endowment Fund for Education (Lembaga Pengelola Dana Pendidikan/LPDP), Ministry of Finance of the Republic of Indonesia, for providing financial support that contributed to the completion of this study.
This systematic review was supported by the Indonesia Endowment Fund for Education (Lembaga Pengelola Dana Pendidikan / LPDP), Ministry of Finance of the Republic of Indonesia, through scholarships awarded to the authors.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
© 2026 Wiliem Souhaly J et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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| # | Наименование патента |
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| 1 | NANOVESICLES, METHODS, AND SYSTEMS FOR DIAGNOSIS AND PROGNOSIS OF CANCER |