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

MicroRNAs in gastrointestinal cancer: a novel biomarker and its
clinical application

Yukiharu Hiyoshi, Masayuki Watanabe
Department of Gastroenterological Surgery, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan.
Correspondence to: Dr. Masayuki Watanabe, 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. E-mail: masayuki.watanabe@jfcr.or.jp

ABSTRACT
Gastrointestinal (GI) cancers remain one of the most common malignancies and are the major cause of cancer deaths worldwide.
Signifi cant advancements have improved our understanding of the pathogenesis and pathology of GI cancers, but high mortality rates,
an unfavorable prognosis, and lack of clinical predictive biomarkers provide an impetus to investigate novel diagnostic/prognostic
markers and therapeutic targets for GI cancers. MicroRNAs (miRNAs) are short (19-24 nucleotides), non-coding RNA molecules
that regulate gene expression at the post-transcriptional level, thus playing an important role in modulating various biological
processes. This includes developmental processes, proliferation, apoptosis, metabolism and differentiation, all involved in initiation
and progression of various human cancers. Aberrant miRNA expression profi les have been observed in various cancer types at
different stages, suggesting their potential as diagnostic and prognostic biomarkers. Due to their tumor- and tissue-specifi c
expression profi les, stability, and the availability of robust clinical assays for their detection in serum as well as in formalin-fi xed
tissue samples, miRNAs have emerged as attractive candidates for diagnostic and prognostic applications. This review summarizes
recent research supporting the utility of miRNAs as novel diagnostic/prognostic tools and therapeutic targets, thus potentially
illuminating future treatment strategies for GI cancers.
Key words: Biomarker, gastrointestinal cancer, microRNA, therapeutic target

Introduction mRNA degradation initiated by miRNA-guided rapid
deadenylation. It has been estimated that 60% of
[2]
Gastrointestinal (GI) cancers represent malignant tumors
of the GI tract and accessory organs of digestion including human protein coding genes are subject to regulation
[3]
esophagus, stomach, liver, biliary tract, pancreas, by miRNAs. They act as master regulators for many
small intestine, large intestine and rectum. GI cancers important biological processes including ontogeny,
are collectively the major cause of cancer-related to cell proliferation, apoptosis, migration, differentiation,
morbidity and mortality worldwide. Current multimodal metabolism, stress, viral infection, cancer initiation and
[1]
treatment strategies including surgery, radiotherapy, progression and drug resistance. [4-7] In addition, several
and/or chemotherapy have marginally improved curative miRNAs may also be useful for diagnostic, prognostic
expectations and quality of life of patients; however, the and therapeutic applications in GI cancers. [8-12]
effectiveness of these new tools depends largely on the Numerous investigations on screening for altered
stage in which tumors are detected. Previous investigators expression of miRNAs in various types of cancer have
have tried to identify more specifi c and sensitive novel been conducted during the past decade, with more and
biomarkers and therapeutic targets for better diagnosis more functional validations in recent years. Although
and management of lethal GI cancers.
the majority of such studies have so far focused on
MicroRNAs (miRNAs) are short, non-coding RNA miRNA profi ling to identify specifi c miRNA species
molecules of approximately 19-24 nucleotides and determining their role in the biology of GI cancers,
involved in post-transcriptional regulation of gene another great potential for miRNA profi ling lies in their
expression. miRNAs bind to the 3’-untranslated region
of mRNA, leading to either translational repression or This is an open access article distributed under the terms of the Creative
Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows
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How to cite this article: Hiyoshi Y, Watanabe M. MicroRNAs in
gastrointestinal cancer: a novel biomarker and its clinical application.
DOI: J Cancer Metastasis Treat 2015;1:144-55.
10.4103/2394-4722.161617
Received: 07-06-2015; Accepted: 29-06-2015.

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