A new chromosomal abnormality in acute lymphoblastic leukemia (ALL) that appears to work in concert with another mutation to give rise to cancer has been identified by scientists. They revealed that the latest anomaly is particularly common in children with Down syndrome.
The findings have already resulted in new diagnostic tests and potential tools for tracking a patient's response to treatment. The research, led by scientists from St. Jude Children's Research Hospital, also highlights a new potential ALL treatment. Clinicians are already planning trials of an experimental medication targeting one of the altered genes.
This study is published in the October 18 online edition of
Nature Genetics.
"A substantial proportion of children with ALL lack one of the previously identified, common chromosomal abnormalities. Also, children with Down syndrome have an increased risk of ALL, but the reasons why are unclear," said Charles Mullighan, M.D., Ph.D., assistant member in the St. Jude Department of Pathology. Mullighan is senior author of the study, which involved scientists from 10 institutions in the U.S. and Italy. "Our results have provided important data regarding the mechanisms contributing to leukemia in these cases," he said.
Instead of the normal pairs of 23 chromosomes, individuals with Down syndrome inherit an extra copy of one chromosome, in this case chromosome 21. Chromosomes are made of DNA and carry the genes that serve as the assembly and operations manual for life. Down syndrome is associated with a variety of medical and developmental problems, including a 10Ž-to-20fold increased risk of ALL. But patients with Down syndrome rarely have the genetic and chromosomal alterations commonly associated with childhood ALL. Until recently the genetic basis of the elevated risk for these patients was unknown.
