Body Abnormalities, Childhood Cancer May Share Genes
THURSDAY, Jan. 3 -- Dutch scientists have discovered that children who have cancer also have more body anomalies, such as asymmetric limbs and curvature of the spine.
This suggests that the same genetic defect underlies both the cancer and the anomaly, raising hopes that genetic information may help identify individuals predisposed to develop cancer.
"This is an excellent study, with very large numbers of patients, and it shows that we're beginning to understand that there are certain genetic changes that predispose individuals to developing various cancers," said Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, La.
"The good news in childhood cancer is that many of them are highly curable," said Brooks. Hopefully we'll be able to use the information in this study to better follow patients who have a genetic predisposition and be able to diagnose cancers sooner."
Another expert agreed.
"The authors have identified many anomalies that are more likely to be found in a group of children with cancer. Any child with cancer and an anomaly deserves a complete genetic evaluation," said Dr. Stephanie Sacharow, a medical geneticist at the University of Miami Miller School of Medicine.
The study, led by Dr. Johannes Merks of the Academic Medical Center in Amsterdam, was published in the Jan. 2 issue of the Journal of the American Medical Association.
Certain genetic syndromes have already been linked with an increased risk for developing childhood cancer.
For instance, Gorlin syndrome (characterized by a broad face and possibly organ deformities) is linked with an increased risk for basal cell carcinoma. Rubinstein-Taybi syndrome (associated with certain physical features and developmental abnormalities) is linked with meningioma, or benign brain tumors.
This study involved nearly 1,100 patients: 898 long-term survivors of childhood cancers and 175 children newly diagnosed with cancer. These children were compared with more than 1,000 children who did not have cancer but who were examined for 683 physical abnormalities in the same way.
Children who had cancer also had more major and minor abnormalities, such as uneven limbs, broad hands or feet, prominent ears and curvature of the spine.
Just under 27 percent of cancer patients had one or more major abnormalities, compared with 15.5 percent of controls. There were two or more abnormalities present in 5.1 percent of patients versus 1.6 percent of controls; while three or more abnormalities were found in 0.9 percent of patients and no controls.
One or more minor anomalies were present in 65.1 percent of patients versus 56.2 percent of controls; two or more minor abnormalities were present in 32.8 percent of patients versus 22.1 percent of controls; while three or more such abnormalities were found in 15.2 percent of patients compared with 8.3 percent of controls.
Almost 4 percent of cancer patients had a clinical genetic syndrome and 14 different abnormalities were significantly linked with childhood cancer.
The mean ages of the two groups of participants were widely divergent, with cancer patients at 21.2 years and controls at 10.4 years, but the authors stated that they only looked at abnormalities that were not associated with a particular age.
All participants were white, eliminating the possibility that ethnicity influenced the prevalence of different cancers or different abnormalities.
"The importance of this is not necessarily in the clinical practice but rather in the fact that as we put this information together, you can then eventually link the actual genes that are involved in producing a particular abnormality and that -- in the long run, not in the short run -- may be quite significant in looking at the potential for explanation and eventually cure," noted Dr. Ludovico Guarini, director of pediatric hematology/oncology at Maimonides Cancer Center in New York City.
The subject of diagnosis and identification of high-risk individuals is trickier, he added.
"Gene mutations which are associated with cancer can give you a hint and sometimes even a solid lead, but they by no means identify the individuals who will develop cancer. They will identify individuals who are somewhat at increased risk," Guarini said.
There's more on childhood cancer at the U.S. National Cancer Institute.
Posted: January 2008