Chronic myeloid leukaemia (CML) affects a type of white blood cell called a myeloid cell. These cells are a middle step between stem cells and fully-formed white blood cells.
People with CML produce too many granulocytes, a specific type of myeloid cell, that are not fully formed. This is why you may hear CML referred to as ‘chronic granulocytic leukaemia’ (CGL). Over time, these abnormal cells fill the bone marrow, which reduces the number of normal cells in the blood.
CML is not classified into different stages, but it does have three recognised phases: ‘chronic’, ‘accelerated’ and ‘blast crisis’. Very few patients progress beyond the chronic phase today due to the effectiveness of modern treatment.
CML is defined by the presence of a ‘Philadelphia Chromosome’ which forms when parts of your DNA are exchanged between two chromosomes. This causes two different genes (called ‘ABL’ and ‘BCR’) that are normally completely separate, to fuse together and promote uncontrolled cell growth.
Name: Chronic Myeloid Leukaemia (CML)
Cell type: Myeloid cells, in particular granulocytes
Frequency: 750 / year in the UK
UK transplants: 49 in 2016
Risk: More common in people over 65
Treatment: Tyrosine Kinase Inhibitors (TKI) and possibly a stem cell transplant
Other info: TKIs allow most CML patients to live long and healthy lives
Most patients with CML are diagnosed during the chronic phase, when treatment with a type of drug called Tyrosine Kinase Inhibitors (TKIs) is possible. Some TKIs are designed to stop cancer cells growing by targeting the Philadelphia Chromosome.
Stem cell transplants are now only recommended for people with CML that hasn’t responded to at least two TKIs. This is usually less than 10% of all cases.
If you do need a transplant, it will be an allograft transplant – when stem cells are donated to you by someone else.
Information published: 17/01/18
Next review due: 17/01/21