Faulty gene linked to chronic leukaemia

BMJ 1999; 318 doi: (Published 09 January 1999) Cite this as: BMJ 1999;318:78
  1. Richard Woodman
  1. London

    Researchers have discovered that a faulty gene may be responsible for many cases of chronic lymphocytic leukaemia, the commonest form of leukaemia in older people.

    It is already known that patients with the rare genetic disorder ataxia telangiectasia are more susceptible to lymphoid malignancies, probably because they have inherited two inactive versions of the ATM gene, and therefore damaged cells cannot be killed through apoptosis. But the latest research shows that loss of expression of the ATM protein also plays a part in the development of sporadic cases of chronic leukaemia (Lancet 1999;353:26-9).

    Genetic analysis of 32tissue samples from patients with chronic lymphatic leukaemia detected mutations in ATM in six tumours; in two of these six cases they were germline mutations, indicating ATM carrier status. Expression of ATM protein was impaired in eight of 20tumours analysed.

    Malcolm Taylor, professor of cancer genetics at the University of Birmingham and lead researcher, said: “We have suspected for some time that a number of patients with this type of leukaemia could be carriers of a faulty gene. But the fact that we have been able to isolate the specific gene and show that it could run in families is certainly a major step forward. The discovery means we can start looking for new ways to repair the defective gene and ultimately prevent this type of blood cancer developing.”

    In the more immediate future, Professor Taylor said that it might be possible to exploit the fact that patients with impaired ATM genes are more sensitive to radiotherapy than are patients with normal ATM.

    The researchers do not yet know how ATM contributes to the development of chronic lymphatic leukaemia, but they point out that the protein is involved in mediating the p53 gene response during apoptosis.

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    Researchers have identified mutations in some chronic leukaemia cases

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