Researchers Discover Genetic Changes In Child Leukemia
Scientists may have gained new insights into the genetic changes in cancer cells that trigger relapse in patients with acute lymphoblastic leukemia.
ALL, a cancer of the blood and bone marrow is the most common type of childhood cancer. Writing in the journal Science on Thursday, scientists described key genetic differences in cancer cells of children with ALL when they were first diagnosed compared to when they had a relapse.
The genetic changes in the cancer cells in relapsed ALL patients often affected the biological machinery involving white blood cells called B cells as well as tumor suppression genes, the researchers said.
Rarely did the changes affect genes directly involved in regulating responsiveness to cancer drugs, they said.
"If we are to develop new selective and less toxic treatments for leukemia, we have to have a complete understanding of all of the different genetic changes that contribute to leukemia and contribute to this process of relapse," said Dr. Charles Mullighan of St. Jude Children’s Research Hospital in Memphis, Tennessee, one of the researchers.
Although, ALL is curable, only about 30 percent of children who suffer a relapse survive.
Scientists hope their discovery will help them develop drugs that can disrupt the relapse process.
"That’s our ultimate goal," Mullighan said.
The researchers compared the genomes of cancer cells of 61 children with ALL when they were initially diagnosed and after they had relapsed.
"The key finding in our work is that in the majority of cases, relapse is arising from a cell already present at the time of diagnosis," St. Jude’s Dr. James Downing, another of the researchers, said in a statement. "That cell is selected for during treatment and then subsequently emerges as basis for relapse."
Mullighan said the cure rate for children with ALL exceeds 80 percent around the world. But perhaps 20 percent to 25 percent of children with ALL suffer a relapse.
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