‘Junk DNA’ could detect breast and bowel cancer

Washington: A type of genetic rogue elements, produced by DNA sequences commonly known as ‘junk DNA’, could help diagnose breast and bowel cancer, according to researchers at The University of Nottingham.

Led by Dr Cristina Tufarelli, in the School of Graduate Entry Medicine and Health Sciences, the researchers found that seven of these faulty genetic elements — known as chimeric transcripts — are more common in breast cancer cells. Five were only present in breast cancer cells while two were found in both normal and breast cancer cells. The rogue elements are produced by DNA sequences called LINE-1 (L1). While they have been labelled as ‘junk DNA’, it is clear that some of these sequences have important roles in the genome, such as influencing when genes are switched on. L1s carry a switch that is able to randomly turn on nearby genes. When genes are inappropriately switched on in this way they make the genetic rogue elements that can sabotage the normal functioning of cells. To avoid the potentially damaging effects of these rogue elements, normal cells silence L1s with a chemical ‘off switch’. In cancerous cells this ‘off switch’ is often missing, leading to the production of these genetic rogue elements. “This study has generated new research tools to investigate the role of ‘junk DNA’ in cancer development. The next step is to find out if the switching on of these genes is driving cancer or if they are a result of the cancer. Even if they are innocent bystanders of cancer they could be useful biomarkers helping us to diagnose or monitor the disease,” said Tufarelli. The researchers extended their studies to look at two bowel cancer cell lines. They found two of the genetic rogue elements in invasive bowel cancer cell lines, but not in the pre-invasive cells, suggesting that these sequences could play a role in cancer progression. “If this ‘junk DNA’ does turn out to play a role in cancer then we could be at the tip of the iceberg in understanding a completely new mechanism behind the disease. If we do find out that they are playing a role then they could be useful targets for new treatments,” said Tufarelli. The research is published in this month’s Genomics journal. -ANI