Editorial
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Oncol. Oct 10, 2015; 6(5): 80-88
Published online Oct 10, 2015. doi: 10.5306/wjco.v6.i5.80
New insights into tumor dormancy: Targeting DNA repair pathways
Elizabeth B Evans, Shiaw-Yih Lin
Elizabeth B Evans, Shiaw-Yih Lin, Department of Systems Biology, the University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States
Author contributions: Evans EB and Lin SY contributed equally to this work.
Supported by The DOD Innovator and Scholar Concept Award, No. W81XWH-12-1-0372.
Conflict-of-interest statement: The authors declare no conflicts of interest regarding this manuscript.
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: Shiaw-Yih Lin, PhD, Deputy Chair, Department of Systems Biology, the University of Texas MD Anderson Cancer Center, 2.SCR3.2020, 7435 Fannin St., Houston, TX 77030, United States. sylin@mdanderson.org
Telephone: +1-713-5634217 Fax: +1-713-5634235
Received: April 29, 2015
Peer-review started: April 29, 2015
First decision: June 4, 2015
Revised: July 8, 2015
Accepted: July 24, 2015
Article in press: July 27, 2015
Published online: October 10, 2015
Processing time: 167 Days and 5.9 Hours
Abstract

Over the past few decades, major strides have advanced the techniques for early detection and treatment of cancer. However, metastatic tumor growth still accounts for the majority of cancer-related deaths worldwide. In fact, breast cancers are notorious for relapsing years or decades after the initial clinical treatment, and this relapse can vary according to the type of breast cancer. In estrogen receptor-positive breast cancers, late tumor relapses frequently occur whereas relapses in estrogen receptor-negative cancers or triple negative tumors arise early resulting in a higher mortality risk. One of the main causes of metastasis is tumor dormancy in which cancer cells remain concealed, asymptomatic, and untraceable over a prolonged period of time. Under certain conditions, dormant cells can re-enter into the cell cycle and resume proliferation leading to recurrence. However, the molecular and cellular regulators underlying this transition remain poorly understood. To date, three mechanisms have been identified to trigger tumor dormancy including cellular, angiogenic, and immunologic dormancies. In addition, recent studies have suggested that DNA repair mechanisms may contribute to the survival of dormant cancer cells. In this article, we summarize the recent experimental and clinical evidence governing cancer dormancy. In addition, we will discuss the role of DNA repair mechanisms in promoting the survival of dormant cells. This information provides mechanistic insight to explain why recurrence occurs, and strategies that may enhance therapeutic approaches to prevent disease recurrence.

Keywords: Quiescence, Homologous recombination, Non-homologous end joining, Tumor dormancy, DNA repair

Core tip: One of the main causes of metastasis is tumor dormancy in which cancer cells remain concealed, asymptomatic, and untraceable over a prolonged period of time. Recent studies have suggested that DNA repair mechanisms may contribute to the survival of dormant cancer cells. Under certain conditions, dormant cells can re-enter into the cell cycle and resume proliferation leading to recurrence. Understanding the molecular and cellular regulators underlying the transition from tumor dormancy to metastatic disease may provide insight into how recurrence occurs and also discover strategies that may enhance therapeutic approaches to prevent metastatic cancer.