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Mizejewski. J Cancer Metastasis Treat 2018;4:27 Journal of Cancer
DOI: 10.20517/2394-4722.2018.20 Metastasis and Treatment

Commentary Open Access

Cancer, circulating tumor cells, and metastasis:
could protein-derived peptide fragments impede

brain metastases?

Gerald J. Mizejewski

Division of Translational Medicine, Molecular Diagnostics Laboratory, Wadsworth Center, New York State Department of
Health, Albany, NY 12201-0509, USA.

Correspondence to: Dr. Gerald J. Mizejewski, Division of Translational Medicine, Molecular Diagnostics Laboratory, Wadsworth
Center, New York State Department of Health, PO Box 509, Empire State Plaza, Albany, NY 12201-0509, USA. E-mail: gerald.
mizejewski@health.ny.gov

How to cite this article: Mizejewski GJ. Cancer, circulating tumor cells, and metastasis: could protein-derived peptide fragments
impede brain metastases? J Cancer Metastasis Treat 2018;4:27. http://dx.doi.org/10.20517/2394-4722.2018.20

Received: 8 Mar 2018 First Decision: 23 Mar 2018 Revised: 22 May 2018 Accepted: 23 May 2018 Published: 11 Jun 2018
Science Editors: William Schiemann Copy Editor: Jun-Yao Li Production Editor: Huan-Liang Wu

Abstract
The majority of cancer deaths can be attributed to cancer cell metastases that migrate to distant target organs. Brain
metastases constitute one of the leading causes of morbidity and mortality among cancer patients, occurring in about
40% of patients with metastatic disease. Thus, there exists an unmet need for early detection, diagnosis, and treatment
directed against early stage cancer cell metastasis. Previous studies have reported the development of methods to
detect and identify early circulating tumor cells (CTCs) in the bloodstream prior to their seeding into distant organs.
Using a comprehensive analysis of total CTCs mRNA content, investigators have developed a mRNA “transcriptome
signature” of 126 genes involved in CTC metastatic events. The genes were parsed into various metastatic-related
activities indicating that CTCs sustained a semi-dormancy state bent on: (1) stress survival; (2) metabolic maintenance;
(3) DNA and translational stability; and (4) chemotactic pro-inflammatory capabilities. These activities suggested
that CTCs might be susceptible to interactions with protein-derived peptide segments whose actions are involved with
metastatic activities such as cell invasiveness, contact, adhesion, motility, spreading, and migration. The use of protein-
derived (encrypted) peptides to impede CTC metabolic activities and disrupt signaling pathways could have therapeutic
potential in patients with early metastatic disease.

Keywords: Breast cancer, brain, metastasis, peptides, plasma proteins, tumor cells, circulation, transcriptome

INTRODUCTION
Cancer metastases to the brain have been reported to occur in 10% to 20% of adult patients with malignant

© The Author(s) 2018. Open Access This article is licensed under a Creative Commons Attribution 4.0
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