Telomere length can act as stopwatch to predict progression of leukaemia: Research

Cancer Research UKJun 11 2010

Broken cell 'stopwatch' could lead to blood test to signal how fast leukaemia will progress

Scientists have pinpointed key changes to the telomeres in the cells of leukaemia patients which could play a crucial role in the earliest stages of the disease, according to research published online in the journal Blood.

The research, funded by Cancer Research UK and Leukaemia & Lymphoma Research, used pioneering techniques for measuring the length of tiny structures known as telomeres - repeating sections of DNA which protect the ends of chromosomes during cell division.

Each time a cell divides the telomeres get shorter, limiting the cell's lifespan.

But some cancer cells manage to bypass this safety check, allowing them to divide uncontrollably until the telomeres become so short they leave the chromosome ends completely exposed.

This makes them prone to fusing together causing instability and large-scale DNA mutations that can speed up cancer progression.

The discovery raises the prospect of developing a test to predict how quickly the telomeres are degrading which in turn would signal how fast the leukaemia was progressing.

It could also be a marker to help diagnose the disease earlier.

Dr Duncan Baird, lead author from Cardiff University, said: "This is the first time we've been able to directly show that shortened telomeres could trigger the progression of cancer.

"Our research shows that telomere length could act as a kind of stopwatch to predict how fast the disease might progress in cancer patients.

"Being able to detect key changes in the cell that trigger the progression of leukaemia is exciting - it could one day lead to a blood test to predict how aggressive a patient's cancer is, helping doctors decide on the best treatment option.

"We're now looking to see if telomeres fusing together may be a driving force in the progression of other types of cancer, such as bowel cancer."

The researchers looked at blood samples from 41 chronic lymphocytic leukaemia (CLL) patients at different stages of the disease. They extracted chromosomes from the blood of these patients and measured the length of their telomeres.

The results showed that the cancer cells of patients at the most advanced stages of disease were more likely to have fused telomeres, suggesting that such events play a major role in the progression of the disease in these patients.

Dr David Grant, scientific director at Leukaemia & Lymphoma Research, said: "The discovery that blood cancer cells multiply uncontrollably because of permanent damage to their telomeres is extremely significant. This finding could lead to new ideas on how to deal with the serious genetic damage that promotes cancer growth and the design of new drugs to target the problem."

Dr Lesley Walker, director of cancer information at Cancer Research UK, said: "This discovery is incredibly exciting, especially if it can also be used to monitor disease progression in other types of cancer cell.

"Understanding the key events that trigger cancer in cells is crucial as it opens up the door for new drug targets for slowing the progression of the disease."