Observational Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 14, 2016; 22(26): 6083-6088
Published online Jul 14, 2016. doi: 10.3748/wjg.v22.i26.6083
High circulating tumor cell concentrations in a specific subtype of gastric cancer with diffuse bone metastasis at diagnosis
Kazuhiro Shimazu, Koji Fukuda, Taichi Yoshida, Masahiro Inoue, Hiroyuki Shibata
Kazuhiro Shimazu, Koji Fukuda, Taichi Yoshida, Masahiro Inoue, Hiroyuki Shibata, Department of Clinical Oncology, Graduate School of Medicine, Akita University, Akita 0108543, Japan
Author contributions: Shibata H designed the study and wrote this manuscript; Shimazu K acquired and analyzed the data; Fukuda K, Yoshida T and Inoue M participated in acquisition and interpretation of the data.
Institutional review board statement: This study was approved by the Akita University School of Medicine Ethics Committee (#828).
Informed consent statement: Informed consent and an agreement to publish were obtained from all patients.
Conflict-of-interest statement: There is no conflict of interest to be declared.
Data sharing statement: Participants gave informed consent for data sharing, and further the presented data are anonymized.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Hiroyuki Shibata, Professor, Department of Clinical Oncology, Graduate School of Medicine, Akita University, 3 Akita Prefecture, Akita Akita 010-8543, Japan. hiroyuki@med.akita-u.ac.jp
Telephone: +81-18-8846262 Fax: +81-18-8846455
Received: February 11, 2016
Peer-review started: February 23, 2016
First decision: March 21, 2016
Revised: April 27, 2016
Accepted: May 21, 2016
Article in press: May 23, 2016
Published online: July 14, 2016
Processing time: 145 Days and 20.5 Hours
Abstract

AIM: To clarify the biological feature contributing to gastric cancer with diffuse bone metastases at diagnosis.

METHODS: The participants visited the Department of Clinical Oncology, Akita University Hospital, from January 2014 to August 2015. The selection criterion for gastric cancer with diffuse bone metastases at diagnosis includes over 29 hot spots of bone scintigraphy. Circulating tumor cell were collected from 20 mL of peripheral venous blood drawn using a CellSearch kit and a CellTracks AutoPrep system by SRL, a clinical laboratory. The endpoints of this study were correlations between circulating tumor cells (CTC) count and therapeutic outcomes.

RESULTS: Among 39 patients with gastric cancer, 5 patients met the criterion. The incidence of this subtype was 12.8%. CTC counts ranged from 235 to 6440 cells/7.5 mL of peripheral blood (median of 1724). These values were much higher than common gastric cancers (2 cells). In chemo-sensitive cases, CTC counts decreased within 14 d (median) from 275, 235 and 1724 to 2, 7 and 66, respectively. On the other hand, CTC counts increased after treatment failure or insensitive case from 2, 7 and 6440 to 787, 513 and 7885, respectively. The correlation between CTC count and survival time showed a trend, but did not reach significance (Y = 234.6 - 0.03X, P = 0.085).

CONCLUSION: High CTC count is a biological hallmark of this subtype, and can be used as a direct and definitive indicator of therapeutic outcome.

Keywords: Bone metastasis; Circulating tumor cell; Gastric cancer; Predictive biomarker; Prognostic biomarker

Core tip: It has been reported in many times that a specific subtype of gastric cancer characterized with diffuse bone metastases at diagnosis, rapid progression and poorer prognosis apparently exists in almost one of ten gastric cancers. However, the basic and biological features of this subtype are not specified until today. In this study, we identified high number of circulating tumor cell of this subtype, and considered that circulating tumor cells (CTC) is responsible for the clinical features described above. CTC is not only a biological hallmark of this subtype, but also informative as a predictive or prognostic biomarkers.