1 May 2014

Genetics of Leukaemia

From Our Changing World, 9:20 pm on 1 May 2014

Leukaemia is a cancer of the blood or bone marrow, usually marked by an increase of immature white blood cells. But the term applies to a whole spectrum of conditions, each caused by a different kind of damage to a gene. Every day, six New Zealanders are diagnosed with a blood cancer or related condition, and you can find more information at Leukaemia and Blood Cancer New Zealand or the Australian Leukaemia Foundation.

The bone marrow contains blood stem cells, which under normal circumstances mature into red cells, white cells and platelets and are eventually released into the blood stream. Leukaemia begins in these developing blood cells, in most cases through a spontaneous mutation in a gene that is involved in the maturation process. As a result, there are too many immature blood cells in the blood stream, crowding out healthy red cells (resulting in anaemia), white cells (resulting in an increase in infections) and platelets, which play an essential role in blood clotting.

In this interview, University of Otago hematologist Ian Morison reflects on the progress in diagnosis and treatment of leukaemias brought about by advancements in DNA technologies and genome sequencing. The perhaps best known example is chronic myeloid leukemia, which is caused by a genetic translocation (parts of two chromosomes, 9 and 22, swapping places) that became known as the Philadelphia Chromosome. The resulting fusion gene codes for a new protein, which is only found in patients. During the 1990, a drug was developed specifically against that protein and made this once-fatal cancer treatable.

Research fellow Euan Rodger also discusses a New Zealand example, involving a Southland family with one person who developed myelodysplastic syndrome, a condition that is based on a chromosomal rearrangement. Euan leads a project in the Morison lab using next-generation sequencing to establish a genetic profile of this condition, and the team believes that the chromosomal inversion results in a disruption of a gene, which may contribute to the syndrome.

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