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Analytical Cellular Pathology
Volume 2016 (2016), Article ID 1628057, 12 pages
http://dx.doi.org/10.1155/2016/1628057
Research Article

In Vivo Flow Cytometry of Circulating Tumor-Associated Exosomes

1Department of Otolaryngology-Head and Neck Surgery, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
2Arkansas Nanomedicine Center, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
3Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA

Received 2 June 2016; Accepted 1 September 2016

Academic Editor: Giovanni Tuccari

Copyright © 2016 Jacqueline Nolan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Circulating tumor cells (CTCs) demonstrated the potential as prognostic markers of metastatic development. However, the incurable metastasis can already be developed at the time of initial diagnosis with the existing CTC assays. Alternatively, tumor-associated particles (CTPs) including exosomes can be a more valuable prognostic marker because they can be released from the primary tumor long before CTCs and in larger amount. However, little progress has been made in high sensitivity detection of CTPs, especially in vivo. We show here that in vivo integrated photoacoustic (PA) and fluorescence flow cytometry (PAFFC) platform can provide the detection of melanoma and breast-cancer-associated single CTPs with endogenously expressed melanin and genetically engineered proteins or exogenous dyes as PA and fluorescent contrast agents. The two-beam, time-of-light PAFFC can measure the sizes of CTCs and CTPs and identify bulk and rolling CTCs and CTC clusters, with no influence on blood flow instability. This technique revealed a higher concentration of CTPs than CTCs at an early cancer stage. Because a single tumor cell can release many CTPs and in vivo PAFFC can examine the whole blood volume, PAFFC diagnostic platform has the potential to dramatically improve (up to 105-fold) the sensitivity of cancer diagnosis.