Cited by 167Nanoparticle-Based Drug DeliveryUltrasound and Hyperthermia ApplicationsAngiogenesis and VEGF in Cancer

The 35th Anniversary of the Discovery of EPR Effect: A New Wave of Nanomedicines for Tumor-Targeted Drug Delivery—Personal Remarks and Future Prospects

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Maeda, Hiroshi·2021·Journal of Personalized Medicine

Abstract

This Special Issue on the enhanced permeability and retention (EPR) effect commemorates the 35th anniversary of its discovery, the original 1986 Matsumura and Maeda finding being published in Cancer Research as a new concept in cancer chemotherapy. My review here describes the history and heterogeneity of the EPR effect, which involves defective tumor blood vessels and blood flow. We reported that restoring obstructed tumor blood flow overcomes impaired drug delivery, leading to improved EPR effects. I also discuss gaps between small animal cancers used in experimental models and large clinical cancers in humans, which usually involve heterogeneous EPR effects, vascular abnormalities in multiple necrotic foci, and tumor emboli. Here, I emphasize arterial infusion of oily formulations of nanodrugs into tumor-feeding arteries, which is the most tumor-selective drug delivery method, with tumor/blood ratios of 100-fold. This method is literally the most personalized medicine because arterial infusions differ for each patient, and drug doses infused depend on tumor size and anatomy in each patient. Future developments in EPR effect-based treatment will range from chemotherapy to photodynamic therapy, boron neutron capture therapy, and therapies for free radical diseases. This review focuses on our own work, which stimulated numerous scientists to perform research in nanotechnology and drug delivery systems, thereby spawning a new cancer treatment era.

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Crossref · 10.3390/jpm11030229

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  • Many clinical cancers such as late-stage and refractory tumors are associated with poor blood flow due to coagulation and thrombi formation, exhibiting poor EPR effect.

    “However, many clinical cancers such as late-stage tumors and refractory tumors are associated with poor blood flow due to the coagulation and thrombi formation exhibiting poor EPR effect [7,8,9,10,11,12].”

    From Approaches to Improve EPR-Based Drug Delivery for Cancer Therapy and Diagnosis (2023) · cites this paper as [7]

    Section 1.3 says large advanced tumors often have occluded or embolized vessels and describes poor blood flow or weak EPR effects in some human cancers. Section 3.1 says the EPR effect is often reduced in clinical settings when blood flow is impaired. The copy does not specifically establish coagulation and thrombus formation as the cause or identify refractory tumors as a group with poor EPR effects. (LLM, conf=0.85)

    Experimental — accuracy not yet measured
  • The EPR effect can be enhanced by modifying vascular intermediaries such as angiotensin II, nitroglycerin or NO, CO, and enzyme inhibitors.

    “The EPR effect can be enhanced by modifying vascular intermediaries such as angiotensin II, nitroglycerin or NO, CO, and enzyme inhibitors [7,8,9,10].”

    From Approaches to Improve EPR-Based Drug Delivery for Cancer Therapy and Diagnosis (2023) · cites this paper as [7]

    Section 1.3 (page unavailable) identifies angiotensin II–induced high blood pressure as an EPR-effect enhancer. Section 3.1 (page unavailable) lists nitroglycerin and angiotensin-converting enzyme inhibitors among enhancers, but the retrieved passages do not establish CO or NO themselves as enhancers; searches for those terms did not resolve that gap. (LLM, conf=0.86)

    Experimental — accuracy not yet measured
  • Because tumor blood flow and vascular permeability are significantly varied from each other, the EPR effect may not be beneficial for all solid tumors.

    “However, because tumor blood flow and vascular permeability are significantly varied from each other, the EPR effect may not be beneficial for all solid tumors.194”

    From Smart nanoparticles for cancer therapy (2023) · cites this paper as [194]

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Research works printed but not linked: 1

  1. [43]Maeda H. Islam W. Overcoming barriers for tumor-targeted drug delivery: The power of macromo-lecular anticancer drugs with the EPR effect and the modulation of vascular physiology Polymer-Protein Conjugation: From PEGylation and Beyond Pasut G. Zalipsky S. Elsevier Amsterdam, The Netherlands 2020 41 58

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Authors
Maeda, H.
Affiliations
Tohoku University (JP)
Corresponding author
Maeda, Hiroshi
Venue
Journal of Personalized Medicine
Publisher
MDPI AG
Published
2021-03-22
Volume
11
Issue
3
Pages
229
ISSN
2075-4426 (ISSN-L)
OpenAlex
W3138405372
Cited by
167
References
87
Citations by year
2026: 24 · 2025: 23 · 2024: 29 · 2023: 35 · 2022: 40 · 2021: 15 · 2012: 1
FWCI
2.06
Type
journal article
Language
en
Open access
Locations
  • Journal of Personalized Medicine (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
Japan Society for the Promotion of Science (18H04059, 29400001)
Topics
  • Physical Sciences › Materials Science › Biomaterials › Nanoparticle-Based Drug Delivery
  • Physical Sciences › Engineering › Biomedical Engineering › Ultrasound and Hyperthermia Applications
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Angiogenesis and VEGF in Cancer
Keywords
enhanced permeability and retention effect, anticancer drug delivery, nanomedicine, tumor perfusion, tumor vasculature, arterial infusion, tumor emboli, tumor necrosis, photodynamic therapy, boron neutron capture therapy, cancer chemotherapy, personalized medicine

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