RESEARCHERS, led by a team at Newcastle University, have found that people born with a rare abnormality of their chromosomes have a massively increased risk of a rare childhood leukaemia.
In this abnormality, two specific chromosomes are fused together but become prone to catastrophic shattering.
The finding could lead to better treatment for other types of cancer, as the abnormalities are more common in some types.
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Acute lymphoblastic leukaemia, or ALL, is the most common childhood cancer.
Scientists previously found that a small group of ALL patients have repeated sections of chromosome 21 in the genomes of their leukaemia cells.
This form of ALL – iAMP21 ALL – requires more intensive treatment than many other types of ALL. The scientists used modern DNA analysis methods to reconstruct the sequence of genetic events that lead to iAMP21 ALL.
The team noticed that some patients with iAMP21 ALL were born with an abnormality in which chromosome 15 and chromosome 21 are fused together. The researchers wanted to discover if this type of fusion (known as a Robertsonian translocation) was connected with this rare form of ALL. They found that the joining of the two chromosomes increases a person’s risk of developing the rare iAMP21 form of ALL by 2,700 fold.
“Advances in treatment are improving patients’ outcomes, but iAMP21 ALL patients require more intensive chemotherapy than other leukaemia patients,” says Professor Christine Harrison, co-lead author from Newcastle University.
“Although rare, people who carry this specific joining together of chromosomes 15 and 21 are specifically and massively predisposed to iAMP21 ALL.
“We have been able to map the roads the cells follow in their transition from a normal genome to a leukaemia genome. And the lessons we are are learning with this should be able to be applied to other, more common types of cancer.”