Copyright
©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
Association between white opaque substance under magnifying colonoscopy and lipid droplets in colorectal epithelial neoplasms
Keisuke Kawasaki, Makoto Eizuka, Shotaro Nakamura, Masaki Endo, Shunichi Yanai, Risaburo Akasaka, Yosuke Toya, Yasuko Fujita, Noriyuki Uesugi, Kazuyuki Ishida, Tamotsu Sugai, Takayuki Matsumoto
Keisuke Kawasaki, Shotaro Nakamura, Shunichi Yanai, Risaburo Akasaka, Yosuke Toya, Takayuki Matsumoto, Division of Gastroenterology, Department of Internal Medicine, Iwate Medical University, Morioka 020-8505, Japan
Makoto Eizuka, Yasuko Fujita, Noriyuki Uesugi, Kazuyuki Ishida, Tamotsu Sugai, Department of Diagnostic Pathology, Iwate Medical University, Morioka 020-8505, Japan
Masaki Endo, Kaiunbashi Endoscopy Clinic, Morioka 020-0022, Japan
Author contributions: Kawasaki K designed the study, and was involved in patients’ management, performed endoscopic examinations and drafted the manuscript; Eizuka M reviewed the histological specimens and was responsible for the pathological diagnosis; Nakamura S, Endo M, Yanai S, Akasaka R, Toya Y, Fujita Y, Uesugi N and Ishida K participated in helped to draft the manuscript; Sugai T reviewed the histological specimens and was responsible for the pathological diagnosis; Matsumoto T critically reviewed and revised the manuscript; all authors have read and approved the final version of the manuscripts.
Institutional review board statement: The protocol of this retrospective study was approved by the Institutional Review Board at Iwate Medical University.
Informed consent statement: Patients were not required to give informed consent as this is a retrospective study.
Conflict-of-interest statement: The authors have no conflicts of interest to declare.
Data sharing statement: No additional data are available.
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: Keisuke Kawasaki, MD, PhD, Doctor, Division of Gastroenterology, Department of Internal Medicine, Iwate Medical University, 19-1, Uchimaru, Morioka 020-8505, Japan. kkeisuke@iwate-med.ac.jp
Telephone: +81-19-6515111 Fax: +81-19-6526664
Received: October 25, 2017
Peer-review started: October 26, 2017
First decision: November 21, 2017
Revised: November 30, 2017
Accepted: December 4, 2017
Article in press: December 4, 2017
Published online: December 21, 2017
ARTICLE HIGHLIGHTS
Research background
White opaque substance (WOS) under magnifying narrow-band imaging (M-NBI) endoscopy is a novel endoscopic finding for the diagnosis of gastrointestinal tract neoplasms. In previous studies, WOS has been shown to contain lipid droplets. However, the association between the distribution of the lipid droplets and endoscopically verified WOS in colorectal neoplasms remains unclear.
Research motivation
The elucidation of WOS or lipid droplets in colorectal epithelial tumors will help the diagnosis and treatment of colorectal epithelial tumors.
Research objectives
To examine the association between WOS and histologically verified lipid droplets in colorectal epithelial neoplasms.
Research methods
We conducted this retrospective study involving 129 lesions of endoscopically or surgically resected colorectal epithelial neoplasms observed by M-NBI colonoscopy. Immunohistochemistry was used to stain tumors with a monoclonal antibody specific to adipophilin as a marker of lipids. The expression and distribution of adipophilin were compared between WOS-positive and WOS-negative lesions and among tumors classified by histologic type and depth of invasion.
Research results
81 lesions were positive for WOS and 48 lesions were negative for WOS. The rate of adipophilin expression was significantly higher in WOS-positive lesions (95.1%) than in WOS-negative lesions (68.7%) (P = 0.0001). The incidence of deep adipophilin expression was higher in WOS-positive lesions (24.7%) than in WOS-negative lesions (4.2%) (P = 0.001). The incidence of deep expression was predominant among cancers with massive submucosal invasion (62.5%) compared to adenoma (7.2%) and high-grade dysplasia or cancers with slight submucosal invasion (12.7%) (P = 0.0001).
Research conclusions
The distribution of lipid droplets may be closely associated with the visibility of WOS under M-NBI colonoscopy, and with histologic grade and depth of tumor invasion.
Research perspectives
Our study showed that WOS under M-NBI colonoscopy appears to represent lipid droplets and the distribution of lipid droplets may be closely associated with the visibility of WOS with histologic grade and depth of tumor invasion. The accumulation of lipid droplets may directly or indirectly represent the malignant potential of colon cancer cells. Further prospective studies are warranted to establish the clinical significance of WOS for the diagnosis and treatment of colorectal epithelial tumors and the association between lipid droplets and WOS under NBI.
