Published online Feb 10, 2017. doi: 10.5306/wjco.v8.i1.67
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: 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.