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Cited by 1,423Extracellular vesicles in diseaseCellular transport and secretionNanoparticle-Based Drug Delivery

Biogenesis of extracellular vesicles (EV): exosomes, microvesicles, retrovirus-like vesicles, and apoptotic bodies

Open access
Akers, Johnny C., Gonda, David, Kim, Ryan, Carter, Bob S., Chen, Clark C.·2013·Journal of Neuro-Oncology
DOI 10.1007/s11060-013-1084-8PMC PMC5533094
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Abstract

Recent studies suggest both normal and cancerous cells secrete vesicles into the extracellular space. These extracellular vesicles (EVs) contain materials that mirror the genetic and proteomic content of the secreting cell. The identification of cancer-specific material in EVs isolated from the biofluids (e.g., serum, cerebrospinal fluid, urine) of cancer patients suggests EVs as an attractive platform for biomarker development. It is important to recognize that the EVs derived from clinical samples are likely highly heterogeneous in make-up and arose from diverse sets of biologic processes. This article aims to review the biologic processes that give rise to various types of EVs, including exosomes, microvesicles, retrovirus like particles, and apoptotic bodies. Clinical pertinence of these EVs to neuro-oncology will also be discussed.

AI snapshot

Written from the paper’s full text.

TL;DR

Extracellular vesicles (EVs) are a heterogeneous mix of exosomes, microvesicles, retrovirus-like particles, and apoptotic bodies that differ in biogenesis, size, and marker profile. The review argues that these differences matter for neuro-oncology biomarker and therapeutic development, while current isolation and marker definitions remain imperfect.

Key findings

  • EVs arise through distinct routes: exosomes from endosomal multivesicular bodies, microvesicles from outward plasma membrane budding, retrovirus-like particles from retroviral protein-driven budding, and apoptotic bodies from programmed cell death.
  • Reported size ranges overlap: exosomes are 30–100 nm, microvesicles 50–2000 nm, retrovirus-like particles 90–100 nm, and apoptotic bodies 500–4000 nm, with smaller 50–500 nm vesicles also released during apoptosis.
  • Candidate markers include CD63/CD9 for exosomes, ARF6 and VAMP3 for microvesicles, Gag for retrovirus-like particles, and thrombospondin/C3b for apoptotic bodies, but the review notes that marker sensitivity and specificity have not been carefully validated.
  • Clinically, EV cargo can protect tumor-derived RNA and protein, and examples include detection of EGFRvIII, IDH-1, and c-myc; a microfluidic μNMR device detected glioblastoma-associated proteins with sensitivity orders of magnitude above Western blotting and ELISA and tracked clinical response in serial serum samples.

Methods

  • Narrative review of published literature on EV biogenesis, isolation, surface markers, and clinical applications, with emphasis on neuro-oncology.
  • Synthesizes cell biology studies, marker studies, and clinical biomarker/therapeutic reports rather than presenting new experimental data.
  • No systematic search strategy or primary sample collection is described.

Limitations

  • The paper states that EV terminology is not standardized, that marker studies were largely performed in non-neoplastic cell lines, and that biogenesis remains incompletely understood; ESCRT-independent exosomes may lack standard markers such as CD63 or CD9.
  • The paper states that tumor-derived EVs are a small minority among biofluid EVs, creating sensitivity challenges, and that current isolation often relies on size/density or CD63, which may not be specific to one EV type.
  • Evident from the text: as a narrative review, it does not provide primary data or a systematic methodology, and its proposed marker schema requires further validation.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1007/s11060-013-1084-8

Cites

126 of 126 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

25 of 47 cited sources checked · 8 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Extracellular vesicles are secreted by both normal and cancerous cells as a means of cell-to-cell communication.

    “These vesicles are secreted by both normal cells and cancerous cells as means of cell-to-cell communication [2-5].”
    Quote in the paperNot a substantial claim2 of 4 sources checked
    • cites [2] Raposo G et al (1996) B lymphocytes secrete antigen-presenting vesicles. J Exp Med 183(3):1161–1172 source

      The Results (p. 1165) show that exosomes released by B-cell lines stimulated T cells, supporting a form of cell-to-cell signaling. The Materials and Methods identify the human B-cell lines as EBV-transformed, while the Discussion (p. 1169) reports only preliminary observations of exosomes on physiological immune cells and says their role in vivo remains to be established. The paper does not establish the broad claim that both normal and cancerous cells secrete vesicles as a means of communication. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [3] Blanchard N et al (2002) TCR activation of human T cells induces the production of exosomes bearing the TCR/CD3/zeta complex. J Immunol 168(7):3235–3241 source
    • cites [4] Andre F et al (2004) Exosomes as potent cell-free peptide-based vaccine. I. Dendritic cell-derived exosomes transfer functional MHC class I/peptide complexes to dendritic cells. J Immunol 172(4):2126–2136 source
    • cites [5] Taylor DD, Akyol S, Gercel-Taylor C (2006) Pregnancy-associated exosomes and their modulation of t cell signaling. J Immunol 176(3):1534–1542 source
  • Premisecitation

    The contents of released extracellular vesicles mirror aspects of the secreting cell.

    “the contents of the vesicles released mirror aspects of the secreting cell. [1]”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [1] Skog J et al (2008) Glioblastoma microvesicles transport RNA and proteins that promote tumour growth and provide diagnostic biomarkers. Nat Cell Biol 10(12):1470–1476 source
  • Interpretationcitation

    Genetic information can also be transferred by uptake of apoptotic bodies.

    “These results suggest that genetic information can also be transferred by uptake of apoptotic bodies.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [114] Bergsmedh A et al (2001) Horizontal transfer of oncogenes by uptake of apoptotic bodies. Proc Natl Acad Sci USA 98(11):6407–6411 source
  • Premisecitation

    Microvesicles arise through direct outward budding and fission of the plasma membrane.

    “The mode of biogenesis of exosomes is distinct from vesicles that arise through direct outward budding and fission of the plasma membrane (Figure 4). To distinguish these vesicles by their mode of biogenesis, the latter class of vesicles is frequently referred to as microvesicles [59].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [59] Cocucci E, Racchetti G, Meldolesi J (2009) Shedding microvesicles: artefacts no more. Trends Cell Biol 19(2):43–51 source
  • Interpretationreasoning

    RLPs may be a constituent of EVs isolated from patient biofluids.

    “These results suggest that RLPs may be a constituent of the EVs isolated from patient biofluids.”
    Quote in the paperSubstantial claim
  • May combine two claims. 15
  • Classified as probably not a substantial claim. 5

  • May combine two claims.

    Premisecitation

    ILV formation requires two distinct processes: organization of the endosome membrane into tetraspanin-enriched microdomains (TEMs) and ESCRT complexes.

    “Work in yeast [28-31] and other tissue culture models [32-34] suggests that ILV formation requires two distinct processes. The first involves the organization of the endosome membrane into specialized units highly enriched for a class of membrane proteins called tetraspanins [35].”
    • Also stated in: § Exosomes · plain
      “The second step in ILV/exosome formation involves a series of complexes called Endosomal Sorting Complex Required for Transport, or ESCRTs for short. There are four multi-protein complexes required for ILV formation and they are termed ESCRT 0, I, II, and III [39-41].”
    Quote in the paperNot a substantial claim3 of 8 sources checked
    • cites [28] Odorizzi G, Babst M, Emr SD (1998) Fab1p PtdIns(3)P 5-kinase function essential for protein sorting in the multivesicular body. Cell 95(6):847–858 source
    • cites [29] Reggiori F, Pelham HRB (2001) Sorting of proteins into multivesicular bodies: ubiquitin-dependent and -independent targeting. EMBO J 20(18):5176–5186 source

      The section 'Identification of proteins in internal vesicles' reports that multivesicular-body formation in yeast is blocked in vps4 mutants. 'Ubiquitylation as a sorting signal in late endosomes' proposes that some cargo partitions into an endosomal membrane domain with different properties. Neither passage establishes that ILV formation requires two distinct processes involving tetraspanin-enriched microdomains and ESCRT complexes; the tetraspanin statement in the citing sentence is separately cited to [35]. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [30] Nickerson DP et al (2010) Regulators of Vps4 ATPase activity at endosomes differentially influence the size and rate of formation of intralumenal vesicles. Mol Biol Cell 21(6):1023–1032 source

      The Introduction (page unavailable) says ESCRT complexes mediate packaging into intralumenal vesicles, supporting the ESCRT part of the claim. Our copy does not describe tetraspanin-enriched microdomains or establish that ILV formation requires the two distinct processes claimed. In the citing sentence, the tetraspanin-specific statement is separately cited to [35]. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites [31] Babst M (2005) A protein’s final ESCRT. Traffic 6(1):2–9 source

      The Abstract (page not supplied) states that ESCRT complexes are required for the formation of multivesicular-body lumenal vesicles. The paper does not identify tetraspanin-enriched microdomains as a second required process; its MVB Vesicle Formation and Dynamics section instead discusses a possible role for lipids in membrane invagination. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [32] Hurley JH, Emr SD (2006) The ESCRT complexes: structure and mechanism of a membrane-trafficking network. Annu Rev Biophys Biomol Struct 35:277–298 source
    • cites [33] Katzmann DJ, Odorizzi G, Emr SD (2002) Receptor downregulation and multivesicular-body sorting. Nat Rev Mol Cell Biol 3(12):893–905 source
    • cites [34] Slagsvold T et al (2006) Endosomal and non-endosomal functions of ESCRT proteins. Trends Cell Biol 16(6):317–326 source
    • cites [35] Pols MS, Klumperman J (2009) Trafficking and function of the tetraspanin CD63. Exp Cell Res 315(9):1584–1592 source

  • May combine two claims.

    Premisecitation

    Exosomes are formed within the endosomal network; intraluminal vesicles bud into late endosomes (multi-vesicular bodies), and fusion of late endosomes with the plasma membrane secretes 30-100 nm vesicles as exosomes.

    “Exosomes are formed within the endosomal network, a membranous compartment that sorts the various intraluminal vesicles and directs them to their appropriate destinations, including lysosomes and cell surface membranes.”
    • Also stated in: § Exosomes · plain
      “On the other hand, fusion with the plasma membrane results in the secretion of the 30-100 nm vesicles into the extra-cellular space. These excreted vesicles are exosomes.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [27] Sotelo JR, Porter KR (1959) An electron microscope study of the rat ovum. J Biophys Biochem Cytol 5(2):327–342 source

      Text-fig. 2 (p. 340) depicts multivesicular bodies containing small vesicles and apparently discharging their contents in rat egg cytoplasm. The paper does not identify those vesicles as exosomes or describe endosomal sorting, fusion with the plasma membrane, or secretion of 30–100 nm vesicles. (LLM, conf=0.82)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    TSG101 and Alix are two proteins sometimes used as exosome markers.

    “TSG101 and Alix are two other proteins sometimes used as exosome markers [38, 46, 47].”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [38] Kosaka N et al (2010) Secretory mechanisms and intercellular transfer of microRNAs in living cells. J Biol Chem 285(23):17442–17452 source

      The exosome-characterization passage (Figure 2; page unavailable) identifies CD63 as an exosome marker, not Alix or TSG101. The Alix passages (Figure 5; page unavailable) examine its role in miRNA secretion. Searches for TSG101 and for Alix as an exosome marker found no passage supporting the attributed claim. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • cites [46] Lasser C, Eldh M, Lotvall J (2012) Isolation and characterization of RNA-containing exosomes. J Vis Exp 59:e3037 source
    • cites [47] Fernandez-Llama P et al (2012) Tamm-Horsfall protein and urinary exosome isolation. Kidney Int 77(8):736–742 source

  • May combine two claims.

    Premisecitation

    CD9 and CD63 serve as the most commonly used identifiers of exosomes and have been targeted for selective isolation.

    “CD9 and CD63 serve as the most commonly used identifiers of exosomes and have been targeted for selective isolation [37, 38].”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [37] Jansen FH et al (2009) Exosomal secretion of cytoplasmic prostate cancer xenograft-derived proteins. Mol Cell Proteomics 8(6):1192–1205 source

      In “Identification of 44 Tumor-derived Proteins” (page not provided), the paper calls CD9 an established marker of tumor cell-derived exosomes. Its methods and exosome-analysis sections describe purification with anti-CD9 magnetic beads. The cited passages do not establish that CD9 and CD63 are the most commonly used identifiers, or describe CD63-targeted isolation. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites [38] Kosaka N et al (2010) Secretory mechanisms and intercellular transfer of microRNAs in living cells. J Biol Chem 285(23):17442–17452 source

      The exosome-characterization passage (Fig. 2; page unavailable) identifies CD63 as an exosome marker, and its caption reports immunoprecipitating a CD63-positive exosome fraction with an anti-CD63 antibody. Our copy does not identify CD9 as an exosome marker or show its use for selective isolation, and it does not establish that CD9 and CD63 are the most commonly used identifiers. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    CD63 and CD9 are potential exosome markers; ARF6 and VAMP3 are proposed microvesicle markers; TSP and C3b are accepted apoptotic body markers; Gag protein may be an RLP marker.

    “CD63 and CD9 are potential markers of exosomes [22, 117]. Markers of microvesicles are less well established though ARF6 and VCAMP3 are recently proposed [66]. TSP and C3b are generally accepted markers of apoptotic bodies. The RLPs are less well studied though Gag protein may be a marker for this group of EVs (Table 1).”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [22] Escola JM et al (1998) Selective enrichment of tetraspan proteins on the internal vesicles of multivesicular endosomes and on exosomes secreted by human B-lymphocytes. J Biol Chem 273(32):20121–20127 source

      The citation is attached to the exosome-marker sentence, not the subsequent claims about other vesicle types. The Discussion (page unavailable) reports that CD63 is enriched on exosomes, supporting its use as a potential marker. The copy does not identify CD9 as an exosome marker (searched: CD9). (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [117] Bard MP et al (2004) Proteomic analysis of exosomes isolated from human malignant pleural effusions. Am J Respir Cell Mol Biol 31(1):114–121 source
    • cites [66] Muralidharan-Chari V et al (2009) ARF6-regulated shedding of tumor cell-derived plasma membrane microvesicles. Curr Biol 19(22):1875–1885 source

  • May combine two claims.

    Premisecitation

    Microvesicle formation involves phosphatidylserine translocation to the outer membrane leaflet and completion by actin-myosin cytoskeletal contraction.

    “Membrane budding/vesicle formation is induced by translocation of phosphatidylserine to the outer-membrane leaflet [62, 65]. The budding process is completed through contraction of cytoskeletal structures by actin-myosin interactions [66, 67].”
    Quote in the paperNot a substantial claim2 of 4 sources checked
    • cites [62] Zwaal RF, Schroit AJ (1997) Pathophysiologic implications of membrane phospholipid asymmetry in blood cells. Blood 89(4):1121–1132 source
    • cites [65] Hugel B et al (2005) Membrane microparticles: two sides of the coin. Physiology (Bethesda) 20:22–27 source
    • cites [66] Muralidharan-Chari V et al (2009) ARF6-regulated shedding of tumor cell-derived plasma membrane microvesicles. Curr Biol 19(22):1875–1885 source
    • cites [67] McConnell RE et al (2009) The enterocyte microvillus is a vesicle-generating organelle. J Cell Biol 185(7):1285–1298 source

      The citation is attached to the sentence about actin–myosin interactions. The Introduction describes myosin-1a moving microvillar membrane over actin bundles and vesicles shedding from the tips, but the Discussion (‘Myo1a is required for proper LV production’; page unavailable) says its precise role in vesicle formation and release remains unclear. It does not establish that cytoskeletal contraction completes budding. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    mRNA profiling of serum-derived EV contents can discriminate between healthy and glioblastoma-bearing patients, and IDH-1, EGFRvIII, and c-myc alterations have been detected in EVs from glioblastoma or medulloblastoma samples.

    “For example, mRNA profiling of serum derived EV contents can discriminate between healthy and glioblastoma bearing patients [118]. IDH-1 (isocitrate dehydrogenase 1) transcripts have been detected from EVs isolated from the blood of glioblastoma bearing patients using immunoisolations of EVs targeting CD63 [119].”
    • Also stated in: § Clinical Applications · plain
      “Genetic mutations of mRNA such as EGFRvIII has been detected by nested PCR of EVs isolated from the serum of glioblastoma patients [1], and c-myc amplification has been effectively identified in the serum of medulloblastoma xenograft bearing mice [120].”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites [118] Noerholm M et al (2012) RNA expression patterns in serum microvesicles from patients with glioblastoma multiforme and controls. BMC Cancer 12(1):22 source
    • cites [119] Chen C et al (2010) Microfluidic isolation and transcriptome analysis of serum microvesicles. Lab Chip 10(4):505–511 source

      The Results section ('Extraction of RNA from captured microvesicles'; page unavailable) reports less microvesicle RNA in healthy serum than in glioblastoma patient serum. It does not show that mRNA profiles discriminate between the two groups: the two mRNAs tested were detected in both. The IDH-1 statement in the printed sentence carries a different citation and is not attributed to this paper here. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [1] Skog J et al (2008) Glioblastoma microvesicles transport RNA and proteins that promote tumour growth and provide diagnostic biomarkers. Nat Cell Biol 10(12):1470–1476 source

      In the paper’s biomarker results (page not available), EGFRvIII mRNA was detected in serum microvesicles from 7 of 25 glioblastoma patients and in none of 30 normal control sera. That supports a distinction for this specific marker, but not the broader claim that mRNA profiling of serum-derived EVs can discriminate glioblastoma-bearing patients from healthy people generally. The IDH-1 sentence is attached to a different citation and is not assessed here. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    Tumor-derived EVs remain a small minority of total EVs in a biofluid sample, so sensitivity of detection remains a major challenge in tumor-specific biomarker development.

    “Relative to this population, EVs derived from tumors remain a small minority of total EVs isolated in a given biofluid sample [118]. Thus, the sensitivity of detection remains a major challenge in tumor-specific biomarker development.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [118] Noerholm M et al (2012) RNA expression patterns in serum microvesicles from patients with glioblastoma multiforme and controls. BMC Cancer 12(1):22 source

      The Discussion says tumour-derived microvesicles in blood are likely to constitute a relatively small fraction of the total in many cases. The citing sentence presents this as categorical and extends it to biofluid samples generally; the cited paper's passage is qualified and concerns blood. The following sentence about detection sensitivity is the citing authors' inference, not a separately cited claim. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • Rests on an assumption: EVs derived from clinical samples are highly heterogeneous in make-up and arise from diverse biologic processes.
    • Rests on an assumption: There is no general consensus as to the best method for EV isolation.

  • May combine two claims.

    Premisecitation

    Actin-myosin interactions appear critical to formation of all four EV types, and phosphatidylserine translocation to the outer membrane is common to apoptotic bodies and microvesicles.

    “For instance, actin-myosin interactions appear critical to the formation of all four types of EVs [66, 85, 100, 115].”
    • Also stated in: § Potential Surface Markers for Defining Clinically Isolated EVs · hedged
      “As another example, the translocation of phosphatidylserine to the outer membrane appeared a common feature during the formation of both apoptotic bodies and microvesicles [65, 106].”
    Quote in the paperNot a substantial claim3 of 6 sources checked
    • cites [66] Muralidharan-Chari V et al (2009) ARF6-regulated shedding of tumor cell-derived plasma membrane microvesicles. Curr Biol 19(22):1875–1885 source

      The Results section ('ERK facilitates microvesicle shedding by phosphorylating myosin light chain') and Discussion support an actomyosin-dependent mechanism for microvesicle release. They do not establish that actin–myosin interactions are critical to formation of all four EV types. The Results also show phosphatidylserine externalization on microvesicles, but do not establish the stated comparison with apoptotic bodies. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [85] Gladnikoff M et al (2009) Retroviral assembly and budding occur through an actin-driven mechanism. Biophys J 97(9):2419–2428 source

      The Abstract (page unavailable) reports that actin remodeling helps retroviruses assemble and bud, supporting a limited connection between the cytoskeleton and particle formation. It does not establish that actin–myosin interactions are critical to formation of all four EV types; its myosin discussion describes earlier in vitro work, not a test of EV formation. The phosphatidylserine statement is not part of the supplied citing sentence and is not judged here. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [100] Sebbagh M et al (2001) Caspase-3-mediated cleavage of ROCK I induces MLC phosphorylation and apoptotic membrane blebbing. Nat Cell Biol 3(4):346–352 source
    • cites [115] Piper RC, Katzmann DJ (2007) Biogenesis and function of multivesicular bodies. Annu Rev Cell Dev Biol 23:519–547 source
    • cites [65] Hugel B et al (2005) Membrane microparticles: two sides of the coin. Physiology (Bethesda) 20:22–27 source
    • cites [106] Martinez MC, Freyssinet JM (2001) Deciphering the plasma membrane hallmarks of apoptotic cells: phosphatidylserine transverse redistribution and calcium entry. BMC Cell Biol 2:20 source

      The citation is attached to the sentence about actin–myosin interactions in the formation of all four EV types. Our copy’s Background and Results discuss calcium entry and phosphatidylserine externalization during apoptosis, but no passage found addresses actin–myosin interactions or formation of four EV types (searched: actin–myosin, actomyosin, myosin, and EV formation). (LLM, conf=0.75)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    ARF6 overexpression increases microvesicle secretion without significantly altering exosome-sized vesicle secretion, supporting that microvesicle and exosome biogenesis are distinct.

    “In a melanoma model, overexpression of a rho family member, GTP-binding protein ADP-ribosylation factor 6 (ARF6), results in increased microvesicle secretion.”
    • Also stated in: § Microvesicles · plain
      “Interestingly, this signaling cascade does not significantly alter the secretion of vesicles in the size range classically associated with exosomes (50-70 nm vesicles) [66]. These observations provide further support that the biogenesis of microvesicles and exosomes are distinct.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [66] Muralidharan-Chari V et al (2009) ARF6-regulated shedding of tumor cell-derived plasma membrane microvesicles. Curr Biol 19(22):1875–1885 source

      The Results section (‘Phenotypic variations of LOXARF6-GDP and LOXARF6-GTP cell lines’; page unavailable) reports significantly increased vesicle shedding from cells expressing active ARF6 compared with parental cells. The Introduction identifies ARF6 as belonging to the ARF family, not the Rho family as the printed citing sentence states. The Results distinguish the isolated microvesicles from exosomes by size and sedimentation, but do not establish the quote’s additional claim that exosome secretion was not significantly altered. (LLM, conf=0.90)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationreasoning

    Cancer-specific material in EVs isolated from patient biofluids suggests EVs are an attractive platform for biomarker development.

    “The identification of cancer-specific material in EVs isolated from the biofluids (e.g. serum, cerebrospinal fluid, urine) of cancer patients suggests EVs as an attractive platform for biomarker development.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: EVs derived from clinical samples are highly heterogeneous in make-up and arise from diverse biologic processes.
    • Rests on an assumption: Multiple types of EV may be present in a given biofluid.

  • May combine two claims.

    Premisecitation

    Current isolation methods rely largely on size and density variations and/or markers such as CD63, which may or may not be specific to a single type of EV.

    “Current isolation methods rely largely on size and density variations of vesicles and/or markers such as CD63 [126] which may or may not be specific to a single type of EV.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [126]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • Rests on an assumption: There is no general consensus as to the best method for EV isolation.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Each of these EV populations likely harbors distinct vesicular contents.

    “Each of these populations likely harbor distinct vesicular contents.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Tumor-specific genetic and proteomic materials have been described in extracellular vesicles (EVs) derived from clinical biofluids.

    “While tumor specific genetic and proteomic materials have been described in EVs derived from clinical biofluids”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    A microfluidic μNMR chip quantifies glioblastoma-specific EV proteins with sensitivity orders of magnitude above Western blotting and ELISA, and changes in EV protein profiles in serial serum samples appeared to track clinical response.

    “In this study, Shao et al. report the fabrication of a microfluidic chip that quantifies presence of glioblastoma specific proteins, including EGFR, EGFRvIII, podoplanin (PDPN), and IDH1 R132H proteins by a micro-nuclear magnetic resonance (μNMR) [122].”
    • Also stated in: § Clinical Applications · plain
      “This technology allows detection of EV harboring glioblastoma-specific proteins with a sensitivity that is orders of magnitude above existing proteomic methods including, Western blotting and enzyme-linked immunosorbent assays (ELISA).”
    • Also stated in: § Clinical Applications · hedged
      “Furthermore, changes in EV protein profiles in serial serum sampling of glioblastoma patients appeared to closely track eventual clinical response [122].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [122] Alvarez-Erviti L et al (2011) Delivery of siRNA to the mouse brain by systemic injection of targeted exosomes. Nat Biotechnol 29(4):341–345 source

  • May combine two claims.

    Interpretationreasoning

    There has not been a careful assessment of the specificity or sensitivity of exosome biomarkers, and it is unlikely that any single surface marker will define EVs as exosomes.

    “However, there has not been a careful assessment in terms of the specificity or sensitivity by which these biomarkers define exosomes. It is unlikely that any surface marker will single-handedly define EVs as exosomes.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Markers for EV types are established using non-neoplastic cell lines.
    • Rests on an assumption: The cellular processes leading to formation of the various types of vesicles remain incompletely understood.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Extracellular vesicles (EVs) are a mixed population of exosomes, microvesicles, retrovirus-like particles (RLPs), and apoptotic bodies.

    “Current understanding of EVs suggests that the vesicles are a mixed population of exosomes, microvesicles, RLPs, and apoptotic bodies.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Apoptotic bodies are formed only during programmed cell death, are generally larger and contain organelles, and Annexin V, thrombospondin, and C3b serve as well-accepted markers.

    “Whereas exosomes, microvesicles, and RLPs are secreted during normal cellular processes, apoptotic bodies are formed only during programmed cell death.”
    • Also stated in: § Apoptotic Bodies · boosted
      “Annexin V, thrombospondin, and C3b thus, serve as three well-accepted markers of apoptotic bodies [111].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [111] van Engeland M et al (1998) Annexin V-affinity assay: a review on an apoptosis detection system based on phosphatidylserine exposure. Cytometry 31(1):1–9 source

  • May combine two claims.

    Premisecitation

    Retrovirus-like particles (RLPs) resemble retroviral vesicles on EM but are non-infectious, are defined by size 90-100 nm and a subset of retroviral proteins, arise by budding from the plasma membrane, and Gag protein may serve as a marker.

    “Retrovirus-like Particles (RLPs) are those that resemble retroviral vesicles on EM but are non-infectious because they do not contain the full complement of genes required for cellular entry or viral propagation. These vesicles are typically defined by their size (90-100 nm) and the presence of a subset of retroviral proteins [69-72].”
    • Also stated in: § Retrovirus-Like Particles (RLPs) · plain
      “RLPs arise by directly budding from the plasma membrane [83] (Figure 5). However, the mechanism of biogenesis is thought to be distinct from the plasma membrane dynamics related to microvesicle or exosome formation.”
    • Also stated in: § Retrovirus-Like Particles (RLPs) · hedged
      “As such, the Gag protein may serve a marker for RLPs.”
    Quote in the paperNot a substantial claim0 of 5 sources checked
    • cites [69] Bronson DL et al (1979) Induction of retrovirus particles in human testicular tumor (Tera-1) cell cultures: an electron microscopic study. J Natl Cancer Inst 63(2):337–339 source
    • cites [70] Boller K et al (1993) Evidence that HERV-K is the endogenous retrovirus sequence that codes for the human teratocarcinoma-derived retrovirus HTDV. Virology 196(1):349–353 source
    • cites [71] Mueller-Lantzsch N et al (1993) Human endogenous retroviral element K10 (HERV-K10) encodes a full-length gag homologous 73-kDa protein and a functional protease. AIDS Res Hum Retroviruses 9(4):343–350 source
    • cites [72] Dewannieux M, Blaise S, Heidmann T (2005) Identification of a functional envelope protein from the HERV-K family of human endogenous retroviruses. J Virol 79(24):15573–15577 source
    • cites [83] Bieda K, Hoffmann A, Boller K (2001) Phenotypic heterogeneity of human endogenous retrovirus particles produced by teratocarcinoma cell lines. J Gen Virol 82(Pt 3):591–596 source

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    The biogenesis and constitution of EVs derived from clinical biofluids remain poorly understood.

    “the biogenesis and constitution of these vesicles remain poorly understood”
    Quote in the paperNot a substantial claim
20 of 20

  • The paper relies on this without support.

    EVs derived from clinical samples are highly heterogeneous in make-up and arise from diverse biologic processes.

    “It is important to recognize that the EV derived from clinical samples are likely highly heterogeneous in make-up and arose from diverse sets of biologic processes.”

  • The paper relies on this without support.

    Multiple types of EV may be present in a given biofluid.

    “it is important to recognize and understand that multiple types of EV may be present in a given biofluid.”

  • The paper relies on this without support.

    Markers for EV types are established using non-neoplastic cell lines.

    “It is important to recognize that these markers are established using non-neoplastic cell lines.”

  • The paper relies on this without support.

    The cellular processes leading to formation of the various types of vesicles remain incompletely understood.

    “the cellular processes leading to the formation of the various types of vesicles remain incompletely understood.”

  • The paper relies on this without support.

    There is no general consensus as to the best method for EV isolation.

    “There is no general consensus as to the best method for isolation.”
5 of 5

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • There are three major categories of EVs: exosomes, microvesicles, and apoptotic bodies, classified based on their biogenesis mechanism.

    “There are three major categories of EVs, namely exosomes, microvesicles, and apoptotic bodies, which are classified based on their biogenesis mechanism [39, 40].”

    From Extracellular vesicles as nanotheranostic platforms for targeted neurological disorder interventions (2024) · cites this paper as [39]

    The Introduction and Microvesicles section support distinguishing EV types by their biogenesis, and the paper discusses all three named types. However, the Introduction and Concluding Remarks also identify retrovirus-like particles as another EV population, so the paper does not support a classification limited to three categories. Page numbers were not available in our copy. (LLM, conf=0.89)

    Experimental — accuracy not yet measured

  • EVs have been conventionally classified into three main categories: exosomes, microvesicles, and apoptotic bodies based on their biogenesis mechanism.

    “In many prior research into EVs, EVs have been conventionally classified into three main categories: exosomes, microvesicles, and apoptotic bodies based on their biogenesis mechanism [39, 40].”

    From Extracellular vesicles as nanotheranostic platforms for targeted neurological disorder interventions (2024) · cites this paper as [39]

    The Introduction identifies exosomes, microvesicles, and apoptotic bodies as EV types and discusses differences in their biogenesis. It also includes retrovirus-like particles as a fourth type and says EV terminology has not been standardized, so it does not support a conventional classification into exactly three main categories. Page numbers are unavailable in our copy. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Self-check results appear here once an independent check has confirmed them.

Cited works that were retracted

Works this paper cites that were later retracted, from the retraction notices publishers deposit. Major when the notice came out before this paper was published.

  • Cites a retracted work: 10.1016/j.ygyno.2008.04.033

    Info

    The cited work was retracted on 2023-07-20 (notice 10.1016/j.ygyno.2023.06.002), not before this paper was published (2013-03-02).

    Cited work 10.1016/j.ygyno.2008.04.033 · retracted 2023-07-20 · notice 10.1016/j.ygyno.2023.06.002 · this paper published 2013-03-02

  • Cites a retracted work: 10.4049/jimmunol.176.3.1534

    Info

    The cited work was retracted on 2015-06-15 (notice 10.4049/jimmunol.1500893), not before this paper was published (2013-03-02).

    Cited work 10.4049/jimmunol.176.3.1534 · retracted 2015-06-15 · notice 10.4049/jimmunol.1500893 · this paper published 2013-03-02

2 of 2

Cites

2 retracted

Flagged first, then by citations

Research works printed but not linked: 1

  1. Bronson DL et al (1979) Induction of retrovirus particles in human testicular tumor (Tera-1) cell cultures: an electron microscopic study. J Natl Cancer Inst 63(2):337–339

Cited by

Sorted by citations

Related

Authors
Akers, J. C., Gonda, D., Kim, R., Carter, B. S., & Chen, C. C.
Affiliations
University of California San Diego (US)
Corresponding author
Chen, Clark C.
ORCID
Venue
Journal of Neuro-Oncology
Publisher
Springer Science and Business Media LLC
Published
2013-03-02
Volume
113
Issue
1
Pages
1-11
ISSN
  • 0167-594X (ISSN-L)
  • 1573-7373
DOI
10.1007/s11060-013-1084-8
PMC
PMC5533094
OpenAlex
W1990597414
Cited by
1,423
References
125
Citations by year
2026: 74 · 2025: 126 · 2024: 138 · 2023: 153 · 2022: 164 · 2021: 179 · 2020: 135 · 2019: 120 · 2018: 93 · 2017: 72 · 2016: 71 · 2015: 48 · 2014: 39 · 2013: 9
FWCI
5.23
Type
journal article
Language
en
Open access
Licence
www.springer.com/tdm (tdm)
Locations
  • Journal of Neuro-Oncology (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • National Institutes of Health (UH2TR000931, UH3TR000931)
  • National Center for Advancing Translational Sciences
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Extracellular vesicles in disease
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Cellular transport and secretion
  • Physical Sciences › Materials Science › Biomaterials › Nanoparticle-Based Drug Delivery
Keywords
extracellular vesicles, exosomes, microvesicles, apoptotic bodies, vesicle biogenesis, tumor markers, biological fluids, neuro-oncology, tumor-derived extracellular vesicles
MeSH terms
Humans, Retroviridae, Biomarkers, Apoptosis, Exosomes

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-13.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-13.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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