WEDNESDAY, Nov. 23, 2005 (HealthDay News) -- A new study finds that specific genes play a key role in whether a child survives neuroblastoma, a rare but potentially fatal cancer of the nervous system.
Children without the genes had more aggressive cancer and a worse prognosis, according to a study in the Nov. 24 issue of the New England Journal of Medicine.
"We're trying to use information from the cancer itself to determine how aggressively the cancer will behave in patients," said the study's lead author, Dr. John Maris, an associate professor of pediatrics from the Children's Oncology Group at the Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine.
Neuroblastoma is the cause of up to 10 percent of all pediatric cancers, according to an editorial in the same issue of the journal. About 650 children are diagnosed with this cancer each year in the United States, and most -- 90 percent -- are diagnosed in babies and toddlers.
Neuroblastoma is usually a solid tumor that begins in nerve tissue or the adrenal glands. These tumors commonly appear in a child's upper abdomen, neck or chest, according to the National Cancer Institute.
The challenge with this particular type of cancer is that it's unpredictable. Neuroblastoma can resolves on its own, meaning that some children will never require treatment. Others will need surgery, but no other treatment. Still others need aggressive treatment with surgery and chemotherapy, yet their outcomes are usually poor.
"Neuroblastoma has this reputation of being enigmatic," said editorial author, Dr. Brian Kushner, an attending pediatrician at Memorial Sloan-Kettering Cancer Center in New York City. "It's hard to predict which way the disease will behave. In some patients it doesn't regress, but you don't want to treat 100 percent because 10 percent will have a bad outcome. Chemo and radiation can have a major impact on kids who are still growing."
Currently, doctors analyze neuroblastoma tumors to see how many copies of the gene, MYCN, are present. If this gene is duplicated it's called MYCN amplification, and this generally indicates a more aggressive form of neuroblastoma. However, MYCN amplification is only present in about 20 percent of the cases, according to the study.
With the current study, the researchers hoped to hone in on other genetic alterations that might signal more aggressive cancer.
After testing neuroblastoma tumor samples from 915 children, the researchers found that 23 percent had a genetic deletion in chromosome 1 and 34 percent had a deletion in chromosome 11.
The deletions in both chromosome 1 and 11 were associated with an aggressive form of cancer in the presence of MYCN amplification, but the risk for chromosome 1 wasn't as strong without the amplification of MYCN.
The risk from the chromosome 11 deletion appeared to be independent of MYCN amplification, according to the study.
Maris said that researchers will be testing for these genetic deletions and applying that information in treatment decisions and in clinical trials.
"We're now getting a number of markers that might be a sign that a tumor is going to act bad, so instead of observing the cancer, we may want to initiate treatment," said Kushner. "This is another tool that might guide us to what might be best for children."
More information
To learn more about neuroblastoma, visit the National Cancer Institute.
