Like a Butterfly’s Wings

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A single change in a seemingly unimportant region of DNA can have large effects on cancer risk.
Posted On: July 25, 2018
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The flap of a butterfly’s wings is a metaphor for a tiny change that can cause a large difference later.

We’ve long known that DNA is important, because it contains the code for building the proteins that make up our bodies. However, a lot of our DNA—most of it, in fact—does not contain instructions for making proteins. This non-coding DNA was at one point labelled “junk DNA”, as it wasn’t clear what purpose it had if it wasn’t for storing the code for proteins.

Scientists have been discovering that the non-coding DNA is in fact far from “junk”, and is important in the regulation of many of our bodies’ processes.

A recent study by Dr. Hansen He helps underline this point, as changing a single nucleotide (or “letter”) in the DNA code led to patients being at risk for a more aggressive form of prostate cancer.

The team used big data approaches and experimental techniques to identify what changed when a specific region of non-coding DNA called risk-associated SNP rs11672691 locus was altered by one nucleotide. The small change in a seemingly unimportant region of DNA led to a cascade of changes in the cell, like the proverbial flap of a butterfly’s wings that changed the course of a hurricane. In this case, the genetic change ultimately affected a set of other genes that are related to prostate cancer cell growth and spread.

This work helps clarify the importance of some single nucleotide changes. Also, it may allow clinicians to provide patients with the altered SNP rs11672691 DNA with more appropriate treatments and additional vigilance against relapse of their prostate cancer.

This work was supported by the Natural Sciences and Engineering Research Council, the Canadian Institutes of Health Research, the Movember Foundation, Prostate Cancer Canada, the US Department of Defense, The Terry Fox Research Institute, the Ontario Ministry of Research, Innovation, and Science, and The Princess Margaret Cancer Foundation.

Hua JT, Ahmed M, Guo H, Zhang Y, Chen S, Soares F, Lu J, Zhou S, Wang M, Li H, Larson NB, McDonnell SK, Patel P, Liang Y, Yao CQ, van der Kwast T, Lupien M, Feng FY, Zoubeidi A, Tsao MS, Thibodeau SN, Boutros PC, He HH. Risk SNP-mediated promoter-enhancer switching drives prostate cancer through lncRNA PCAT19. Cell. 2018 July. doi: 10.1016/j.cell.2018.06.014.