Interindividual variability is yet to be fully characterized, and for this, optimum patient stratification and companion diagnostics are still lacking. Especially when complex disease phenotypes and/or polygenic diseases are considered, patient monitoring and disease management become rather challenging, while acquired resistance to therapy and/or toxicity events are among the unmet needs in the clinic. No doubt, biomarkers are of great importance to disease management and tailor-made theranostics. Microfluidics has gathered great attention lately, mostly due to its low-invasive nature compared to tissue biopsies. Low invasiveness becomes greatly advantageous for microfluidics practices as the latter mirror cell biology revolutionizing cancer diagnostics and management. Recent advances in microfluidics hold the promise of robust clinical diagnostics after they have demonstrated effective exosome separation. We feel that microfluidics-based exosome isolation techniques, if cost-effective, could be implemented in the clinic and/or resource-scarce settings. This article (a) discusses exosomes, (b) comments on the first microfluidic advances in the field of cancer theranostics, (c) presents such advances in exosomes as complementary to liquid biopsies with an emphasis on circulating tumor cells, and (d) proposes a road map for future developments.

Keywords:
Microfluidics, Cancer, Public health, Exosomes, Liquid biopsies
1.
An T, Qin S, Xu Y, Tang Y, Huang Y, Situ B, Inal JM, Zheng L: Exosomes serve as tumour markers for personalized diagnostics owing to their important role in cancer metastasis. J Extracell Vesicles 2015;4:27522.
2.
Schneider D, Bianchini G, Horgan D, Michiels S, Witjes W, Hills R, Plun-Favreau J, Brand A, Lawler M: Establishing the evidence bar for molecular diagnostics in personalised cancer care. Public Health Genomics 2015;18:349-358.
3.
Senkus E, Kyriakides S, Penault-Llorca F, Poortmans P, Thompson A, Zackrisson S, Cardoso F: Primary breast cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol 2013;24(suppl 6):vi7-vi23.
4.
Cardoso F, Costa A, Norton L, Senkus E, Aapro M, Andre F, Barrios C, Bergh J, Biganzoli L, Blackwell K: ESO-ESMO 2nd international consensus guidelines for advanced breast cancer (ABC2). Breast 2014;23:489-502.
5.
Reck M, Popat S, Reinmuth N, De Ruysscher D, Kerr K, Peters S; ESMO Guidelines Working Group: Metastatic non-small-cell lung cancer (NSCLC): ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Ann Oncol 2014;25:iii27-iii39.
6.
Horwich A, Parker C, Bangma C, Kataja V; ESMO Guidelines Working Group: Prostate cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol 2010;21:v129-v133.
7.
Labianca R, Nordlinger B, Beretta G, Mosconi S, Mandalà M, Cervantes A, Arnold D; ESMO Guidelines Working Group: Early colon cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol 2013;24:vi64-vi72.
8.
Redzic JS, Ung TH, Graner MW: Glioblastoma extracellular vesicles: reservoirs of potential biomarkers. Pharmgenomics Pers Med 2014;7:65-77.
9.
Fenizia F, De Luca A, Pasquale R, Sacco A, Forgione L, Lambiase M, Iannaccone A, Chicchinelli N, Franco R, Rossi A: EGFR mutations in lung cancer: from tissue testing to liquid biopsy. Future Oncol 2015;11:1611-1623.
10.
Lewis AR, Valle JW, McNamara MG: Pancreatic cancer: are “liquid biopsies” ready for prime-time? World J Gastroenterol 2016;22:7175.
11.
Gerlinger M, Rowan AJ, Horswell S, Larkin J, Endesfelder D, Gronroos E, Martinez P, Matthews N, Stewart A and Tarpey P: Intratumor heterogeneity and branched evolution revealed by multiregion sequencing. N Engl J Med 2012;2012:883-892.
12.
Yong E: Cancer biomarkers: written in blood. Nature 2014;511:524-526.
13.
Zhang C, Guan Y, Sun Y, Ai D, Guo Q: Tumor heterogeneity and circulating tumor cells. Cancer Lett 2016;374:216-223.
14.
Schmidt H, Kulasinghe A, Perry C, Nelson C, Punyadeera C: A liquid biopsy for head and neck cancers. Expert Rev Mol Diagn 2016;16:165-172.
15.
Rolfo C, Castiglia M, Hong D, Alessandro R, Mertens I, Baggerman G, Zwaenepoel K, Gil-Bazo I, Passiglia F and Carreca AP: Liquid biopsies in lung cancer: the new ambrosia of researchers. Biochim Biophys Acta 2014;1846:539-546.
16.
Trams EG, Lauter CJ, Salem JN, Heine U: Exfoliation of membrane ecto-enzymes in the form of micro-vesicles. Biochim Biophys Acta 1981;645:63-70.
17.
Johnstone RM, Adam M, Hammond J, Orr L, Turbide C: Vesicle formation during reticulocyte maturation. Association of plasma membrane activities with released vesicles (exosomes). J Biol Chem 1987;262:9412-9420.
18.
Raposo G, Stoorvogel W: Extracellular vesicles: exosomes, microvesicles, and friends. J Cell Biol 2013;200:373-383.
19.
Mittelbrunn M, Gutiérrez-Vázquez C, Villarroya-Beltri C, González S, Sánchez-Cabo F, González MÁ, Bernad A, Sánchez-Madrid F: Unidirectional transfer of microRNA-loaded exosomes from T cells to antigen-presenting cells. Nat Commun 2011;2:282.
20.
Kowal J, Tkach M, Théry C: Biogenesis and secretion of exosomes. Curr Opin Cell Biol 2014;29:116-125.
21.
Gould SJ, Raposo G: As we wait: coping with an imperfect nomenclature for extracellular vesicles. J Extracell Vesicles 2013;2:20389.
22.
Fujita Y, Yoshioka Y, Ochiya T: Extracellular vesicle transfer of cancer pathogenic components. Cancer Sci 2016;107:385-390.
23.
Cocucci E, Racchetti G, Meldolesi J: Shedding microvesicles: artefacts no more. Trends Cell Biol 2009;19:43-51.
24.
Kalra H, Simpson RJ, Ji H, Aikawa E, Altevogt P, Askenase P, Bond VC, Borràs FE, Breakefield X, Budnik V: Vesiclepedia: a compendium for extracellular vesicles with continuous community annotation. PLoS Biol 2012;10: e1001450.
25.
Kim D-K, Kang B, Kim OY, Choi D-s, Lee J, Kim SR, Go G, Yoon YJ, Kim JH, Jang SC: EVpedia: an integrated database of high-throughput data for systemic analyses of extracellular vesicles. J Extracell Vesicles 2013;2:20384.
26.
Mathivanan S, Simpson RJ: ExoCarta: a compendium of exosomal proteins and RNA. Proteomics 2009;9:4997-5000.
27.
Schneider A, Simons M: Exosomes: vesicular carriers for intercellular communication in neurodegenerative disorders. Cell Tissue Res 2013;352:33-47.
28.
Simpson RJ, Lim JW, Moritz RL, Mathivanan S: Exosomes: proteomic insights and diagnostic potential. Expert Rev Proteomics 2009;6:267-283.
29.
Milane L, Singh A, Mattheolabakis G, Suresh M, Amiji MM: Exosome mediated communication within the tumor microenvironment. J Control Release 2015;219:278-294.
30.
Simona F, Laura S, Simona T, Riccardo A: Contribution of proteomics to understanding the role of tumor-derived exosomes in cancer progression: state of the art and new perspectives. Proteomics 2013;13:1581-1594.
31.
Naito Y, Yoshioka Y, Yamamoto Y, Ochiya T: How cancer cells dictate their microenvironment: present roles of extracellular vesicles. Cell Mol Life Sci 2017;74:697-713.
32.
Hoshino A, Costa-Silva B, Shen T-L, Rodrigues G, Hashimoto A, Mark MT, Molina H, Kohsaka S, Di Giannatale A, Ceder S: Tumour exosome integrins determine organotropic metastasis. Nature 2015;527:329-335.
33.
Gonzalez E, Falcón-Pérez JM: Cell-derived extracellular vesicles as a platform to identify low-invasive disease biomarkers. Expert Rev Mol Diagn 2015;15:907-923.
34.
Cappello F, Logozzi M, Campanella C, Bavisotto CC, Marcilla A, Properzi F, Fais S: Exosome levels in human body fluids: a tumor marker by themselves? Eur J Pharm Sci 2017;96:93-98.
35.
Logozzi M, De Milito A, Lugini L, Borghi M, Calabro L, Spada M, Perdicchio M, Marino ML, Federici C, Iessi E: High levels of exosomes expressing CD63 and caveolin-1 in plasma of melanoma patients. PLoS One 2009;4:e5219.
36.
Silva J, Garcia V, Rodriguez M, Compte M, Cisneros E, Veguillas P, Garcia J, Dominguez G, Campos-Martin Y, Cuevas J: Analysis of exosome release and its prognostic value in human colorectal cancer. Genes Chromosomes Cancer 2012;51:409-418.
37.
Hoffman RM, Couper MP, Zikmund-Fisher BJ, Levin CA, McNaughton-Collins M, Helitzer DL, VanHoewyk J, Barry MJ: Prostate cancer screening decisions: results from the National Survey of Medical Decisions (DECISIONS study). Arch Intern Med 2009;169:1611-1618.
38.
Mitchell PJ, Welton J, Staffurth J, Mason MD, Tabi Z, Clayton A: Can urinary exosomes act as treatment response markers in prostate cancer? J Transl Med 2009;7:4.
39.
Kawakami K, Fujita Y, Kato T, Mizutani K, Kameyama K, Tsumoto H, Miura Y, Deguchi T, Ito M: Integrin β4 and vinculin contained in exosomes are potential markers for progression of prostate cancer associated with taxane-resistance. Int J Oncol 2015;47:384-390.
40.
Théry C, Amigorena S, Raposo G, Clayton A: Isolation and characterization of exosomes from cell culture supernatants and biological fluids. Curr Protoc Cell Biol DOI: 10.1002/ 0471143030.cb0322s30.
41.
Alvarez ML, Khosroheidari M, Ravi RK, DiStefano JK: Comparison of protein, microRNA, and mRNA yields using different methods of urinary exosome isolation for the discovery of kidney disease biomarkers. Kidney Int 2012;82:1024-1032.
42.
Witwer KW, Buzas EI, Bemis LT, Bora A, Lässer C, Lötvall J, Nolte EN, Piper MG, Sivaraman S, Skog J: Standardization of sample collection, isolation and analysis methods in extracellular vesicle research. J Extracell Vesicles 2013;2:20360.
43.
Jørgensen M, Bæk R, Pedersen S, Søndergaard EK, Kristensen SR, Varming K: Extracellular vesicle (EV) array: microarray capturing of exosomes and other extracellular vesicles for multiplexed phenotyping. J Extracell Vesicles 2013;2:20920.
44.
Im H, Shao H, Park YI, Peterson VM, Castro CM, Weissleder R, Lee H: Label-free detection and molecular profiling of exosomes with a nano-plasmonic sensor. Nat Biotechnol 2014;32:490-495.
45.
Mizutani K, Terazawa R, Kameyama K, Kato T, Horie K, Tsuchiya T, Seike K, Ehara H, Fujita Y, Kawakami K: Isolation of prostate cancer-related exosomes. Anticancer Res 2014;34:3419-3423.
46.
Meel R, Krawczyk-Durka M, Solinge W, Schiffelers R: Toward routine detection of extracellular vesicles in clinical samples. Int J Lab Hematol 2014;36:244-253.
47.
Bobrie A, Colombo M, Raposo G, Théry C: Exosome secretion: molecular mechanisms and roles in immune responses. Traffic 2011;12:1659-1668.
48.
Parkinson DR, McCormack RT, Keating SM, Gutman SI, Hamilton SR, Mansfield EA, Piper MA, DeVerka P, Frueh FW, Jessup JM: Evidence of clinical utility: an unmet need in molecular diagnostics for patients with cancer. AACR Annu Meet, San Diego, April 2014.
49.
Altman DG, McShane LM, Sauerbrei W, Taube SE: Reporting recommendations for tumor marker prognostic studies (REMARK): explanation and elaboration. BMC Med 2012;10:51.
50.
Horgan D, Lawler M, Brand A: Getting personal: accelerating personalised and precision medicine integration into clinical cancer research and care in clinical trials. Public Health Genomics 2015;18:325-328.
51.
Horgan D: Access for all: a personalised approach. Public Health Genomics 2016;19:129-131.
52.
Hofman P, Popper HH: Pathologists and liquid biopsies: to be or not to be? Virchows Arch 2016;469:601-609.
53.
Liga A, Vliegenthart A, Oosthuyzen W, Dear J, Kersaudy-Kerhoas M: Exosome isolation: a microfluidic road-map. Lab Chip 2015;15:2388-2394.
54.
Kanwar SS, Dunlay CJ, Simeone DM, Nagrath S: Microfluidic device (ExoChip) for on-chip isolation, quantification and characterization of circulating exosomes. Lab Chip 2014;14:1891-1900.
55.
Alix-Panabières C, Pantel K: Circulating tumor cells: liquid biopsy of cancer. Clin Chem 2013;59:110-118.
56.
Bardelli A, Pantel K: Liquid biopsies, what we do not know (yet). Cancer Cell 2017;31:172-179.
57.
Allard WJ, Matera J, Miller MC, Repollet M, Connelly MC, Rao C, Tibbe AG, Uhr JW, Terstappen LW: Tumor cells circulate in the peripheral blood of all major carcinomas but not in healthy subjects or patients with nonmalignant diseases. Clin Cancer Res 2004;10:6897-6904.
58.
De Bono JS, Scher HI, Montgomery RB, Parker C, Miller MC, Tissing H, Doyle GV, Terstappen LW, Pienta KJ, Raghavan D: Circulating tumor cells predict survival benefit from treatment in metastatic castration-resistant prostate cancer. Clin Cancer Res 2008;14:6302-6309.
59.
Krebs MG, Sloane R, Priest L, Lancashire L, Hou J-M, Greystoke A, Ward TH, Ferraldeschi R, Hughes A, Clack G: Evaluation and prognostic significance of circulating tumor cells in patients with non-small-cell lung cancer. J Clin Oncol 2011;29:1556-1563.
60.
Joosse SA, Gorges TM, Pantel K: Biology, detection, and clinical implications of circulating tumor cells. EMBO Mol Med 2015;7:1-11.
61.
Bordi P, Del Re M, Danesi R, Tiseo M: Circulating DNA in diagnosis and monitoring EGFR gene mutations in advanced non-small cell lung cancer. Transl Lung Cancer Res 2015;4:584-597.
62.
Lianidou ES, Strati A, Markou A: Circulating tumor cells as promising novel biomarkers in solid cancers. Crit Rev Clin Lab Sci 2014;51:160-171.
63.
Costa DB: Identification of somatic genomic alterations in circulating tumors cells: another step forward in non-small-cell lung cancer? J Clin Oncol 2013;31:2236-2239.
64.
Powell AA, Talasaz AH, Zhang H, Coram MA, Reddy A, Deng G, Telli ML, Advani RH, Carlson RW, Mollick JA: Single cell profiling of circulating tumor cells: transcriptional heterogeneity and diversity from breast cancer cell lines. PLoS One 2012;7:e33788.
65.
Hayes DF, Cristofanilli M, Budd GT, Ellis MJ, Stopeck A, Miller MC, Matera J, Allard WJ, Doyle GV, Terstappen LW: Circulating tumor cells at each follow-up time point during therapy of metastatic breast cancer patients predict progression-free and overall survival. Clin Cancer Res 2006;12:4218-4224.
66.
Cohen SJ, Punt CJ, Iannotti N, Saidman BH, Sabbath KD, Gabrail NY, Picus J, Morse M, Mitchell E, Miller MC: Relationship of circulating tumor cells to tumor response, progression-free survival, and overall survival in patients with metastatic colorectal cancer. J Clin Oncol 2008;26:3213-3221.
67.
Danila DC, Heller G, Gignac GA, Gonzalez-Espinoza R, Anand A, Tanaka E, Lilja H, Schwartz L, Larson S, Fleisher M: Circulating tumor cell number and prognosis in progressive castration-resistant prostate cancer. Clin Cancer Res 2007;13:7053-7058.
68.
Lianidou ES: Gene expression profiling and DNA methylation analyses of CTCs. Mol Oncol 2016;10:431-442.
69.
Plaks V, Koopman CD, Werb Z: Circulating tumor cells. Science 2013;341:1186-1188.
70.
Strati A, Markou A, Parisi C, Politaki E, Mavroudis D, Georgoulias V, Lianidou E: Gene expression profile of circulating tumor cells in breast cancer by RT-qPCR. BMC Cancer 2011;11:422.
71.
Markou A, Strati A, Malamos N, Georgoulias V, Lianidou ES: Molecular characterization of circulating tumor cells in breast cancer by a liquid bead array hybridization assay. Clin Chem 2011;57:421-430.
72.
Sieuwerts AM, Kraan J, Bolt-de Vries J, van der Spoel P, Mostert B, Martens JW, Gratama J-W, Sleijfer S and Foekens JA: Molecular characterization of circulating tumor cells in large quantities of contaminating leukocytes by a multiplex real-time PCR. Breast Cancer Res Treat 2009;118:455.
73.
Chimonidou M, Strati A, Tzitzira A, Sotiropoulou G, Malamos N, Georgoulias V, Lianidou ES: DNA methylation of tumor suppressor and metastasis suppressor genes in circulating tumor cells. Clin Chem 2011;57:1169-1177.
74.
Chimonidou M, Strati A, Malamos N, Georgoulias V, Lianidou ES: SOX17 promoter methylation in circulating tumor cells and matched cell-free DNA isolated from plasma of patients with breast cancer. Clin Chem 2013;59:270-279.
75.
Markou A, Farkona S, Schiza C, Efstathiou T, Kounelis S, Malamos N, Georgoulias V, Lianidou E: PIK3CA mutational status in circulating tumor cells can change during disease recurrence or progression in patients with breast cancer. Clin Cancer Res 2014;20:5823-5834.
76.
Forshew T, Murtaza M, Parkinson C, Gale D, Tsui DW, Kaper F, Dawson S-J, Piskorz AM, Jimenez-Linan M, Bentley D: Noninvasive identification and monitoring of cancer mutations by targeted deep sequencing of plasma DNA. Sci Transl Med 2012;4:136ra168-136ra168.
77.
Bidard F-C, Fehm T, Ignatiadis M, Smerage JB, Alix-Panabières C, Janni W, Messina C, Paoletti C, Müller V, Hayes DF: Clinical application of circulating tumor cells in breast cancer: overview of the current interventional trials. Cancer Metastasis Rev 2013;32:179-188.
78.
Burtis CA, Ashwood ER, Bruns DE: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Amsterdam, Elsevier Health Sciences, 2012.
79.
Nagrath S, Sequist LV, Maheswaran S, Bell DW, Irimia D, Ulkus L, Smith MR, Kwak EL, Digumarthy S, Muzikansky A: Isolation of rare circulating tumour cells in cancer patients by microchip technology. Nature 2007;450:1235-1239.
80.
Ozkumur E, Shah AM, Ciciliano JC, Emmink BL, Miyamoto DT, Brachtel E, Yu M, Chen P-i, Morgan B, Trautwein J: Inertial focusing for tumor antigen-dependent and -independent sorting of rare circulating tumor cells. Sci Transl Med 2013;5:179ra147-179ra147.
81.
Xu L, Mao X, Imrali A, Syed F, Mutsvangwa K, Berney D, Cathcart P, Hines J, Shamash J, Lu Y-J: Optimization and evaluation of a novel size based circulating tumor cell isolation system. PLoS One 2015;10:e0138032.
82.
Hou J-M, Krebs M, Ward T, Sloane R, Priest L, Hughes A, Clack G, Ranson M, Blackhall F, Dive C: Circulating tumor cells as a window on metastasis biology in lung cancer. Am J Pathol 2011;178:989-996.
83.
Hosokawa M, Kenmotsu H, Koh Y, Yoshino T, Yoshikawa T, Naito T, Takahashi T, Murakami H, Nakamura Y, Tsuya A: Size-based isolation of circulating tumor cells in lung cancer patients using a microcavity array system. PLoS One 2013;8:e67466.
84.
Shao H, Chung J, Balaj L, Charest A, Bigner DD, Carter BS, Hochberg FH, Breakefield XO, Weissleder R, Lee H: Protein typing of circulating microvesicles allows real-time monitoring of glioblastoma therapy. Nat Med 2012;18:1835-1840.
85.
Taller D, Richards K, Slouka Z, Senapati S, Hill R, Go DB, Chang H-C: On-chip surface acoustic wave lysis and ion-exchange nanomembrane detection of exosomal RNA for pancreatic cancer study and diagnosis. Lab Chip 2015;15:1656-1666.
86.
Kharmate G, Hosseini-Beheshti E, Caradec J, Chin MY, Guns EST: Epidermal growth factor receptor in prostate cancer derived exosomes. PLoS One 2016;11:e0154967.
87.
Rupp A-K, Rupp C, Keller S, Brase JC, Ehehalt R, Fogel M, Moldenhauer G, Marmé F, Sültmann H, Altevogt P: Loss of EpCAM expression in breast cancer derived serum exosomes: role of proteolytic cleavage. Gynecol Oncol 2011;122:437-446.
88.
Rabinowits G, Gerçel-Taylor C, Day JM, Taylor DD, Kloecker GH: Exosomal microRNA: a diagnostic marker for lung cancer. Clin Lung Cancer 2009;10:42-46.
89.
Manterola L, Guruceaga E, Pérez-Larraya JG, González-Huarriz M, Jauregui P, Tejada S, Diez-Valle R, Segura V, Samprón N, Barrena C: A small noncoding RNA signature found in exosomes of GBM patient serum as a diagnostic tool. Neuro Oncol 2014;16:520-527.
90.
Ogata-Kawata H, Izumiya M, Kurioka D, Honma Y, Yamada Y, Furuta K, Gunji T, Ohta H, Okamoto H, Sonoda H: Circulating exosomal microRNAs as biomarkers of colon cancer. PLoS One 2014;9:e92921.
91.
Hong C-S, Muller L, Whiteside TL, Boyiadzis M: Plasma exosomes as markers of therapeutic response in patients with acute myeloid leukemia. Front Immunol 2014;5:160.
© 2017 S. Karger AG, Basel
2017
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.