Ancient DNA sequences within human cells can help cancer cells survive: Study

Cancer Research UKMay 7 2010

Mysterious 'ancient' DNA can help cancer cells survive

A new study in the journal Nature Medicine, part-funded by Cancer Research UK, has discovered that ancient DNA sequences within human cells can actually help cancer cells survive - at least in one type of the disease.

Scientists at the University of Leeds, and the Charité University Medical School and Max Delbruck Centre for Molecular Medicine (MDC) in Berlin, Germany focused on Hodgkin's lymphoma, in which certain white blood cells become cancerous.

The study found that these cancerous cells activate many mysterious sections of DNA called long terminal repeats (LTRs) - which are thought to be evolutionary remnants of old viruses - and which are usually 'switched off' as they can potentially cause problems.

One of the LTRs activated in these cells helped them to survive even though they did not possess a crucial signal receptor that normally controls the growth of healthy white blood cells.

The scientists found that this LTR activated a different signal receptor that is usually found in other immune cells. This receptor controlled the growth of the cancer cells, allowing them to survive.

Although the study only looked at lymphoma cells, the scientists suggest these sections of DNA may also play a role in other similar types of cancer.

Professor Constanze Bonifer, from the University of Leeds, explained: "The exact same mechanism could be involved in the development of other forms of blood cancer. This would have implications for diagnosis, prognosis and therapy of these diseases."

Cancer Research UK's science information officer Nell Barrie said: "We are starting to see that these mysterious stretches of ancient DNA can have significant effects in some types of cancer. This important study shows that these 'long terminal repeats' can help cancer cells to survive, but it was carried out in cells grown in the lab, so it will be some time before we see effective cancer treatments based on this discovery."