AccScience Publishing / TD / Online First / DOI: 10.36922/TD025400104
REVIEW ARTICLE

The king without subjects: Targeting tumor microenvironment as an approach to addressing cancer treatment challenges

Somaye Zareian1 Golnaz Bahramali2 Soroush Sardari1*
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1 Drug Design and Bioinformatics Unit, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
2 Department of Hepatitis and AIDS and Blood Borne Diseases, Pasteur Institute of Iran, Tehran, Iran
Tumor Discovery, 025400104 https://doi.org/10.36922/TD025400104
Received: 1 October 2025 | Revised: 25 January 2026 | Accepted: 13 February 2026 | Published online: 12 May 2026
© 2026 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
Abstract

Cancer research has traditionally emphasized tumor cell–intrinsic drivers of malignancy, yet mounting evidence demonstrates that cancer progression, therapeutic resistance, and metastasis are critically shaped by the tumor microenvironment (TME). Rather than serving as a passive scaffold, the TME constitutes a dynamic and heterogeneous ecosystem composed of immune, stromal, and vascular elements that actively regulate tumor behavior. Despite strong biological rationale, therapeutic strategies targeting the TME have produced inconsistent clinical outcomes, with many approaches failing to translate durable benefit to patients. In this review, we critically examine why TME-targeted therapies have underperformed in clinical settings. We synthesize recent literature to highlight key challenges, including cellular and spatial heterogeneity, adaptive resistance mechanisms, unintended depletion of tumor-restraining components, immune-related toxicities, and limitations of current preclinical and clinical trial designs. We argue that non-selective ablation of microenvironmental compartments frequently disrupts protective regulatory functions, thereby undermining therapeutic precision. We further discuss how emerging technologies such as single-cell and spatial multi-omics are reshaping our understanding of TME complexity and enabling more refined therapeutic strategies. Rather than advocating for broad elimination of microenvironmental components, we emphasize the need for selective modulation, functional reprogramming, and biomarker-guided patient stratification. By reframing the TME not simply as a therapeutic target but as a dynamic system requiring precision intervention, this review provides a critical perspective on past failures and outlines rational directions for the next generation of microenvironment-informed cancer therapies.

Keywords
Tumor microenvironment
Single-cell RNA sequencing
Cancer therapeutic strategies
Tumor heterogeneity
Therapy resistance
Precision oncology
Funding
None.
Conflict of interest
The authors declare no competing interests.
References
  1. Yarden Y, Pines G. The ERBB network: At last, cancer therapy meets systems biology. Nat Rev Cancer. 2012;12(8):553-563. doi: 10.1038/nrc3309
  2. Hanahan D, Weinberg RA. Hallmarks of cancer: The next generation. Cell. 2011;144(5):646-674. doi: 10.1016/j.cell.2011.02.013
  3. Lambert A, Pattabiraman D, Weinberg R. Emerging biological principles of metastasis. Cell. 2017;168(4):670- 691. doi: 10.1016/j.cell.2016.11.037
  4. Slamon DJ, Leyland-Jones B, Shak S, et al. Use of Chemotherapy plus a Monoclonal Antibody against HER2 for Metastatic Breast Cancer That Overexpresses HER2. N Engl J Med. 2001;344(11):783-792. doi: 10.1056/nejm200103153441101
  5. Lynch TJ, Bell DW, Sordella R, et al. Activating Mutations in the Epidermal Growth Factor Receptor Underlying Responsiveness of Non–Small-Cell Lung Cancer to Gefitinib. N Engl J Med. 2004;350(21):2129-2139. doi: 10.1056/nejmoa040938
  6. Chapman PB, Hauschild A, Robert C, et al. Improved Survival with Vemurafenib in Melanoma with BRAF V600E Mutation. N Engl J Med. 2011;364(26):2507-2516. doi: 10.1056/nejmoa1103782
  7. Yu HA, Arcila ME, Rekhtman N, Sima CS, Zakowski MF, Pao W, et al. Analysis of Tumor Specimens at the Time of Acquired Resistance to EGFR-TKI Therapy in 155 Patients with EGFR-Mutant Lung Cancers. Clin Cancer Res. 2013;19(8):2240-2247. doi: 10.1158/1078-0432.ccr-12-2246
  8. Wilke H, Muro K, Van Cutsem E, et al. Ramucirumab plus paclitaxel versus placebo plus paclitaxel in patients with previously treated advanced gastric or gastro-oesophageal junction adenocarcinoma (RAINBOW): A double-blind, randomised phase 3 trial. Lancet Oncol. 2014;15(11):1224- 1235. doi: 10.1016/S1470-2045(14)70420-6
  9. Zaarour RF, Ribeiro M, Azzarone B, Kapoor S, Chouaib S. Tumor microenvironment-induced tumor cell plasticity: relationship with hypoxic stress and impact on tumor resistance. Front Oncol. 2023;13:1-17. doi: 10.3389/fonc.2023.1222575
  10. Roma-Rodrigues C, Mendes R, Baptista P V, Fernandes AR. Targeting tumor microenvironment for cancer therapy. Int J Mol Sci. 2019;20(4):840. doi: 10.3390/ijms20040840
  11. Visser KE De, Joyce JA. The evolving tumor microenvironment: From cancer initiation to metastatic outgrowth. Cancer Cell. 2023;41(3):374-403. doi: 10.1016/j.ccell.2023.02.016
  12. Quail DF, Joyce J. Microenvironmental regulation of tumor progression and metastasis. Nat Med. 2013;(11):1423-1437. doi: 10.1038/nm.3394
  13. Kalluri R. The biology and function of fibroblasts in cancer. Nat Rev Cancer. 2016;16(9):582-598. doi: 10.1038/nrc.2016.73
  14. Binnewies M, Roberts E, Kersten K, et al. Understanding the tumor immune microenvironment (TIME) for effective therapy Mikhail. Nat Med. 2018;24(5):541-550. doi: 10.1038/s41591-018-0014-x
  15. Chen DS, Mellman I. Elements of cancer immunity and the cancer – immune set point. Nature. 2017;541(7637):321-330. doi: 10.1038/nature21349
  16. Long GV, Stroyakovskiy D, Gogas H, et al. Dabrafenib and trametinib versus dabrafenib and placebo for Val600 BRAF-mutant melanoma: A multicentre, double-blind, phase 3 randomised controlled trial. Lancet. 2015;386(9992):444-451. doi: 10.1016/S0140-6736(15)60898-4
  17. Topalian SL, Hodi FS, Brahmer JR, et al. Safety, Activity, and Immune Correlates of Anti–PD-1 Antibody in Cancer. N Engl J Med. 2012;366(26):2443-2454. doi: 10.1056/nejmoa1200690
  18. Malfitano AM, Pisanti S, Napolitano F, Di Somma S, Martinelli R PG. Tumor-Associated Macrophage Status in Cancer Treatment. Cancers. 2020;12(7):1987. doi: 10.3390/cancers12071987
  19. Ferrara N, Hillan KJ, Gerber HP, Novotny W. Discovery and development of bevacizumab, an anti-VEGF antibody for treating cancer. Nat Rev Drug Discov. 2004;3(5):391-400. doi: 10.1038/nrd1381
  20. Lindner T, Loktev A, Altmann A, et al. Development of quinoline-based theranostic ligands for the targeting of fibroblast activation protein. J Nucl Med. 2018;59(9):1415- 1422. doi: 10.2967/jnumed.118.210443
  21. Onrust SV, Lamb HM, Balfour J. Rituximab. Drugs. 1999;58(1):79-88. doi: 10.2165/00003495-199958010-00009
  22. Kazazi-Hyseni F, Beijnen JH, Schellens J. Bevacizumab. Oncologist. 2010;15(8):819-825. doi: 10.1634/theoncologist.2009-0317
  23. Sondak VK, Smalley KSM, Kudchadkar R, Grippon S, Kirkpatrick P. Ipilimumab. Nat Rev Drug Discov. 2011;10(6):411-412. doi: 10.1038/nrd3463
  24. Khoja L, Butler MO, Kang SP, Ebbinghaus S, Joshua AM. Pembrolizumab. J Immunother Cancer. 2015;3(1). doi: 10.1186/s40425-015-0078-9
  25. Gunturi A, McDermott DF. Nivolumab for the treatment of cancer. Expert Opin Investig Drugs. 2014;24(2):253-260. doi: 10.1517/13543784.2015.991819
  26. Javle M, Smyth EC, Chau I. Ramucirumab: Successfully targeting angiogenesis in gastric cancer. Clin Cancer Res. 2014;20(23):5875-5881. doi: 10.1158/1078-0432.CCR-14-1071
  27. Matsui J, Yamamoto Y, Funahashi Y, et al. E7080, a novel inhibitor that targets multiple kinases, has potent antitumor activities against stem cell factor producing human small cell lung cancer H146, based on angiogenesis inhibition. Intl J Cancer. 2007;122(3):664-671. doi: 10.1002/ijc.23131
  28. Herbst RS, Soria JC, Kowanetz M, Fine GD, Hamid O, Gordon MS, et al. Predictive correlates of response to the anti-PD-L1 antibody MPDL3280A in cancer patients. Nature. 2014;515(7528):563-567. doi: 10.1038/nature14011
  29. Loizos N, Xu Y, Huber J, et al. Targeting the platelet-derived growth factor receptor A with a neutralizing human monoclonal antibody inhibits the growth of tumor xenografts: Implications as a potential therapeutic target. Mol Cancer Ther. 2005;4(3): 369-380. doi: 10.1158/1535-7163.mct-04-0114
  30. Kim ES. Avelumab: First Global Approval. Drugs. 2017;77(8):929-937. doi: 10.1007/s40265-017-0749-6
  31. Stewart R, Morrow M, Hammond SA, et al. Identification and Characterization of MEDI4736 , an Antagonistic anti-PD-L1 Monoclonal Antibody. Cancer Immunol Res. 2015;3(9):1052-1062. doi: 10.1158/2326-6066.CIR-14-0191
  32. Novartis Pharmaceuticals Corporation. TABRECTA (capmatinib). Updated 2024. Available from https://www.novartis.com/us-en/sites/novartis_us/files/tabrecta.pdf.
  33. Keam SJ. Tremelimumab: First Approval. Drugs. 2023;83(1):93-102. doi: 10.1007/s40265-022-01827-8
  34. Dhillon S. Tebentafusp: First Approval. Drugs. 2022;82(6):703-710. doi: 10.1007/s40265-022-01704-4
  35. First-in-class T cell engager approved for lung cancer. Nat Biotechnol. 2024;42(6):824. doi: 10.1038/s41587-024-02291-3
  36. Hodi FS, O’Day SJ, McDermott DF, et al. Improved Survival with Ipilimumab in Patients with Metastatic Melanoma. N Engl J Med. 363(8):711-723. doi: 10.1056/nejmoa1003466
  37. Özdemir BC, Pentcheva-Hoang T, Carstens JL, et al. Depletion of carcinoma-associated fibroblasts and fibrosis induces immunosuppression and accelerates pancreas cancer with reduced survival. Cancer Cell. 2014;25(6):719- 734. doi: 10.1016/j.ccr.2014.04.005
  38. Yarchoan M, Hopkins A, Jaffee EM. Tumor Mutational Burden and Response Rate to PD-1 Inhibition. N Engl J Med. 2017;377(25):2500-2501. doi: 10.1056/nejmc1713444
  39. Jin, MZ . Jin W. The updated landscape of tumor microenvironment and drug repurposing. Signal Transduct Target Ther. 2020;5(1). doi: 10.1038/s41392-020-00280-x
  40. Jayson GC, Kerbel R, Ellis LM, Harris AL. Antiangiogenic therapy in oncology : current status and future directions. Lancet. 2016;388(10043):518-529. doi: 10.1016/S0140-6736(15)01088-0
  41. Visvader JE. Cells of origin in cancer. Nature. 2011;469(7330):314-322. doi: 10.1038/nature09781
  42. Karaayvaz M, Cristea S, Gillespie SM, et al. Unravelling subclonal heterogeneity and aggressive disease states in TNBC through single-cell RNA-seq. Nat Commun. 2018;9(1). doi: 10.1038/s41467-018-06052-0
  43. Sántha P, Lenggenhager D, Finstadsveen A, et al. Morphological Heterogeneity in Pancreatic Cancer Reflects Structural and Functional Divergence. Cancers. 2021;13(4):895. doi: 10.3390/cancers13040895
  44. Cárdenas-Navia LI, Mace D, Richardson RA, Wilson DF, Shan S, Dewhirst MW. The pervasive presence of fluctuating oxygenation in tumors. Cancer Res. 2008;68(14):5812-5819. doi: 10.1158/0008-5472.CAN-07-6387
  45. Tong Y, Gao W qiang, Liu Y. Metabolic heterogeneity in cancer : An overview and therapeutic implications. Biochim Biophys Acta Rev Cancer. 2020;1874(2):188421. doi: 10.1016/j.bbcan.2020.188421
  46. Finan JM, Guo Y, Goodyear SM, Brody JR. Challenges and Opportunities in Targeting the Complex Pancreatic Tumor Microenvironment. JCO Oncol Adv. 2024;(1). doi: 10.1200/oa-24-00050
  47. Jayathilaka B, Mian F, Au-Yeung G, IJzerman M. Cancer and treatment specific incidence rates of immune- related adverse events induced by immune checkpoint inhibitors: a systematic review. Br J Cancer. 2025;132(1):51-57. doi: 10.1038/s41416-024-02887-1
  48. Shen X, Yang J, Qian G, et al. Treatment-related adverse events of immune checkpoint inhibitors in clinical trials: a systematic review and. Front Oncol. 2024;14:1-10. doi: 10.3389/fonc.2024.1391724
  49. Pozzessere C, Mazini B, Omoumi P, et al. Immune-Related Adverse Events Induced by Immune Checkpoint Inhibitors and CAR-T Cell Therapy: A Comprehensive Imaging-Based Review. Cancers. 2024;16(14):2585. doi: 10.3390/cancers16142585
  50. Huang J, Xiong L, Tang S, Zhao J, Zuo L. Balancing Tumor Immunotherapy and Immune-Related Adverse Events: Unveiling the Key Regulators. IJMS. 2024;25(20):10919. doi: 10.3390/ijms252010919
  51. Zhang C, Wang H, Li X, Jiang Y, Sun G, Yu H. Enhancing antitumor immunity: the role of immune checkpoint inhibitors, anti-angiogenic therapy, and macrophage reprogramming. Front Oncol. 2025;15. doi: 10.3389/fonc.2025.1526407
  52. Xia X, Yang Z, Lu Q, et al. Reshaping the tumor immune microenvironment to improve CAR-T cell- based cancer immunotherapy. Mol Cancer. 2024;23(1). doi: 10.1186/s12943-024-02079-8
  53. Leong SP. Immune responses and immunotherapeutic approaches in the treatment against cancer. Clin Exp Metastasis. 2024;41(4):473-493. doi: 10.1007/s10585-024-10300-7
  54. Zhang H, Li S, Wang D, et al. Metabolic reprogramming and immune evasion: the interplay in the tumor microenvironment. Biomark Res. 2024;12(1):1-25. doi: 10.1186/s40364-024-00646-1
  55. Tang F, Barbacioru C, Wang Y, et al. mRNA-Seq whole-transcriptome analysis of a single cell. Nat Methods. 2009;6(5):377-382. doi: 10.1038/NMETH.1315
  56. Saelens W, Cannoodt R, Todorov H, Saeys Y. A comparison of single-cell trajectory inference methods: towards more accurate and robust tools. bioRxiv. Preprint online 2018. doi: 10.1101/276907
  57. Chen G, Ning B, Shi T. Single-cell RNA-seq technologies and related computational data analysis. Front Genet. 2019;10:1-13. doi: 10.3389/fgene.2019.00317
  58. Babu M, Snyder M. Multi-Omics Profiling for Health. Mol Cell Proteom. 2023;22(6):100561. doi: 10.1016/j.mcpro.2023.100561
  59. Nam AS, Chaligne R, Landau DA. Integrating genetic and non-genetic determinants of cancer evolution by single-cell multi-omics. Nat Rev Genet. 2021;22(1):3-18. doi: 10.1038/s41576-020-0265-5
  60. Bian X, Wang W, Abudurexiti M, et al. Integration Analysis of Single-Cell Multi-Omics Reveals Prostate Cancer Heterogeneity. Adv Sci. 2024;211(18). doi: 10.1002/advs.202305724
  61. Ai D, Du Y, Duan H, Qi J, Wang Y. Tumor Heterogeneity in Gastrointestinal Cancer Based on Multimodal Data Analysis. Genes. 2024;15(9):1207. doi: 10.3390/genes15091207
  62. Trigos AS, Pearson RB, Papenfuss AT, Goode DL. Altered interactions between unicellular and multicellular genes drive hallmarks of transformation in a diverse range of solid tumors. Proc Natl Acad Sci USA. 2017;114(24):6406-6411. doi: 10.1073/pnas.1617743114
  63. Rao A, Barkley D, França GS, Yanai I. Exploring tissue architecture using spatial transcriptomics. Nature. 2021;596(7871):211-220. doi: 10.1038/s41586-021-03634-9
  64. Shah S, Lubeck E, Zhou W, Cai L. seqFISH Accurately Detects Transcripts in Single Cells and Reveals Robust Spatial Organization in the Hippocampus. Neuron. 2017;94(4):752-758.e1. doi: 10.1016/j.neuron.2017.05.008
  65. Gyllborg D, Langseth CM, Qian X, et al. Hybridization-based in situ sequencing (HybISS) for spatially resolved transcriptomics in human and mouse brain tissue. Nucleic Acids Res. 2020;48(19):e112-e112. doi: 10.1093/nar/gkaa792
  66. Lee JH, Daugharthy ER, Scheiman J, et al. Fluorescent in situ sequencing (FISSEQ) of RNA for gene expression profiling in intact cells and tissues Competing financial interests Potential conflicts of interests for. Nat Protoc. 2015;10(3):442-458. doi: 10.1038/nprot.2014.191.

67. Moffitt JR, Hao J, Wang G, Chen KH, Babcock HP, Zhuang X. High-throughput single-cell gene-expression profiling with multiplexed error-robust fluorescence in situ hybridization. Proc Natl Acad Sci USA. 2016;113(39):11046-11051. doi: 10.1073/pnas.1612826113

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Tumor Discovery, Electronic ISSN: 2810-9775 Print ISSN: 3060-8597, Published by AccScience Publishing