Study of ‘looping’ DNA reveals breast cancer link
12 Apr 2018 by Evoluted New Media
Scientists have linked 110 genes to an increased risk of breast cancer in the most comprehensive study ever to unpick the genetics of the disease.
The team from the Institute of Cancer Research looked in detail at 63 areas of the genome that had previously been associated with the risk of breast cancer by mapping studies. They also linked 32 of the new genes to the length of time women survived breast cancer – suggesting these could be important in the development of the disease and potential targets for future treatments.
Dr Olivia Fletcher, Team Leader in Functional Genetic Epidemiology at The Institute of Cancer Research, London, said: “Our study took the high-level maps of breast cancer risk regions and used them to pull out specific genes that seem to be associated with the disease. We studied how DNA forms loops to allow physical interactions between a DNA sequence in one part of the genome and a risk gene in another. Identifying these new genes will help us to understand in much greater detail the genetics of breast cancer risk. Ultimately, our study could pave the way for new genetic tests to predict a woman’s risk, or new types of targeted treatment.”
Finding the genes responsible for the increased risk is not straightforward because small sequences of DNA can interact with completely different parts of the genome through a strange phenomenon known as ‘DNA looping’. These could be studied as the researchers used a technique they developed called Capture Hi-C to study interactions between different regions of the genome.
The team found that some of the 63 regions of the genome were physically interacting with genes more than a million letters of DNA code away. They were able to identify 110 new genes that could potentially be causing an increased risk of breast cancer across 33 of the regions they studied. In the remaining 30 areas, they were unable to find any specific genes. One third of the target genes for which they had patient data – 32 out of 97 – were also linked to survival in women with oestrogen receptor-positive breast cancer, suggesting they play an important role in the disease.
Baroness Delyth Morgan, Chief Executive at Breast Cancer Now, which funded the study, said: “These are really important findings. We urgently need to unravel how the genetic changes in the building blocks of our DNA influence a woman’s risk of breast cancer, and this study adds another vital piece to this jigsaw.”
The study is published in Nature Communications.
