Telomeres: a game-changer in CLL testing

Chronic lymphocytic leukaemia (CLL) is a slowly developing blood cancer in which patients produce mutated versions of white blood cells that build up in the blood, bone marrow and lymph nodes, and crowd out healthy blood cells. It progresses at different rates in different people, and in a third of patients it never progresses at all.

Until now, there has been no accurate test to indicate whether and how fast the cancer will develop for individual patients. A new test, developed by researchers at Cardiff University, measures the length of sections of DNA in cancer cells called telomeres, which are found at the end of chromosomes.

Telomeres shorten every time a cell divides to create a new cell and eventually the chromosome ends are left exposed, leading to extensive DNA damage that speeds up cancer progression. The researchers have found that people who have CLL cells with very short telomeres when diagnosed are much more likely to have a fast-progressing cancer.

It is thought that the test could be a game-changer and could guide decisions on which drugs to give to patients. It also has the potential to change how other cancers, including myeloma and breast cancer, are treated. While previous versions of the test had taken a week to process, results can now be ready in a day.