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Topic: Reviews of Recent Advances in Research and Treatment for
Gastroenterological Malignancies

The clinical signifi cance of circulating tumor cells in gastrointestinal
cancer

Masaaki Iwatsuki , Junji Kurashige , Takatsugu Ishimoto , Keisuke Kosumi , Yoshifumi Baba , Yasuo Sakamoto ,
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Yuji Miyamoto , Naoya Yoshida , Masayuki Watanabe , Hideo Baba 1
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1 Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556,
Japan.
2 Department of Gastroenterological Surgery, Esophageal Cancer Division, Cancer Institute Hospital of Japanese Foundation for Cancer Research,
3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan.
Correspondence to: Dr. Hideo Baba, Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University,
1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan. E-mail: hdobaba@kumamoto-u.ac.jp
ABSTRACT
Circulating tumor cells (CTCs) are originated from the primary tumor lesion into the blood stream. CTCs could lead to recurrence
of gastrointestinal (GI) cancers, even after a curative resection and colonizing in the distant organs to facilitate tumor distant
metastasis; however, it has been challenging in clinic to detect CTCs for a long time, such as detection methodology or molecular
markers for identifi cation of CTCs. This review discussed the recent technical advances and biomarkers in the detection of CTCs
and the molecular mechanism of CTC in cancer progression and metastasis. Moreover, novel concepts, such as cancer stem cells
and epithelial-mesenchymal transition, could lead to CTCs and tumor progression and metastasis. Nevertheless, the involvement
of CTCs varies greatly among cancer types in the GI and much remains to be learned. Thus, further study will provide more
insightful information from a clinical and translational viewpoint to use CTCs for cancer early diagnosis or prediction of tumor
recurrence and investigation of tumor progression and metastasis as well.
Key words: Cancer stem cells, circulating tumor cells, epithelial-mesenchymal transition, gastrointestinal cancer,
tumor progression and metastasis

Introduction Indeed, detection of CTCs becomes a promising
means to early diagnosis and prediction of prognosis
Tumor recurrence often occurs in patients with and tumor recurrence for several types of human
gastrointestinal (GI) cancers, even after a curative resection, cancer. [2-5] Furthermore, the study of CTCs could also
which may be because undetectable tumor cells depositor elucidate the molecular biological profi le of CTC and
enter into the blood stream at the time of operation. In some lead to better understanding of cancer metastasis. To
cases, tumor recurs despite adjuvant chemotherapy after date, standard procedures of CTC detection have to
curative surgery suggesting that chemotherapy failed to be established, and the clinical relevance should be
eradicate all cancer cells that persist after curative surgery. confi rmed by a large-scale clinical study. In this review,
Thus, tumor cells could be disseminated before surgery. we updated and discussed recent progress regarding
The concept of the circulating tumor cells (CTCs) has been, CTCs in GI cancer. These new data could improve our
therefore, established and indicates that tumor cells are in understanding of the mechanisms of cancer progression
blood stream, which will facilitate tumor progression and and metastasis as well as therapy resistance. This
metastasis although detection of CTCs in peripheral blood information may also lead to the development of novel
[1]
was described more than a century ago. Recent advance clinical targets and improve the clinical management of
on research of CTCs largely contributed to diagnosis and GI cancer.
treatment of GI cancers. However, the clinical relevance
of CTC detection in GI cancers is still the subject of This is an open access article distributed under the terms of the Creative
controversies, and their biology is poorly understood. Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows
others to remix, tweak, and build upon the work non-commercially, as long as
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How to cite this article: Iwatsuki M, Kurashige J, Ishimoto T, Kosumi K,
Baba Y, Sakamoto Y, Miyamoto Y, Yoshida N, Watanabe M, Baba H.
The clinical signifi cance of circulating tumor cells in gastrointestinal
DOI: cancer. J Cancer Metastasis Treat 2015;1:130-7.
10.4103/2394-4722.165534
Received: 13-07-2015; Accepted: 18-08-2015.

130 © 2015 Journal of Cancer Metastasis and Treatment ¦ Published by Wolters Kluwer - Medknow