Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Oncol. Feb 10, 2017; 8(1): 67-74
Published online Feb 10, 2017. doi: 10.5306/wjco.v8.i1.67
NDRG2 gene copy number is not altered in colorectal carcinoma
Anders Lorentzen, Cathy Mitchelmore
Anders Lorentzen, Cathy Mitchelmore, Eucaryotic Cell Biology, Department of Science and Environment, Roskilde University, 4000 Roskilde, Denmark
Author contributions: Lorentzen A conceived the idea of the study and performed the experimental analysis; Lorentzen A and Mitchelmore C were both involved in interpretation of data, drafting the article and revising it critically for important intellectual content.
Supported by The Danish Cancer Society, No. DP05117.
Institutional review board statement: Human genomic DNA was purchased from Biochain Inc., whose IRB is registered with the Office for Human Research Protections (OHRP) with the registration number IRB00008283.
Conflict-of-interest statement: There is no conflict of interest.
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: Cathy Mitchelmore, PhD, Associate Professor, Department of Science and Environment, Roskilde University, Universitetsvej 1, Postbox 260, 4000 Roskilde, Denmark. mitch@ruc.dk
Telephone: +45-46743201 Fax:+45-46743011
Received: June 15, 2016
Peer-review started: June 18, 2016
First decision: August 16, 2016
Revised: November 11, 2016
Accepted: December 27, 2016
Article in press: December 28, 2016
Published online: February 10, 2017
Core Tip

Core tip: NDRG2 is a putative tumor suppressor gene whose expression is reduced in many cancer forms, including colorectal carcinoma (CRC). We set out therefore to investigate if down-regulation of NDRG2 expression was due to loss of one or both alleles and/or to other mechanisms. In our paper, we show that allelic loss of NDRG2 is a rare event in CRC. To our knowledge, this is the first study that has specifically investigated gene copy number of NDRG2 in CRC. Furthermore, our results suggest that MYC is amplified in more than 40% of CRC cases. MYC is known to repress transcription of NDRG2. Our results lead us to suggest that it is the transcriptional control of NDRG2 expression, including repression by MYC and epigenetic regulation, that results in decreased NDRG2 mRNA levels in CRC, rather than allelic loss of NDRG2.