CARSON CITY -- Federal researchers have found that children who are part of a Northern Nevada cancer cluster have a variation in a gene that helps combat unsafe chemicals.
Eleven of the 15 children diagnosed in the Fallon leukemia cluster between 1997 and 2001 submitted to DNA testing, and the variation in the gene was found in all 11 children tested. The gene, called SUOX, tells the body how to make sulfite oxidase, an enzyme that changes an unsafe chemical into a safer one.
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The study released by the Centers for Disease Control and Prevention is the latest to suggest genetics and toxins play a role in the cancer cluster plaguing the rural agricultural community.
But Dr. Carol Rubin, chief of the CDC's health studies branch, said the variation in the gene was also found in 40 percent of Fallon children in a comparison, or healthy group.
"The variations may mean something, and they may not mean something," she said. "The fact that all the case children had the variation, and 40 percent of the comparison children did too, is a striking finding.
"At the same time, because both the case and comparison children have the variation, it does not appear to predict leukemia," Rubin said. "It needs to be followed up."
Even if the variation in the SUOX gene adds to the risk for leukemia, CDC officials said, other factors must be involved. Researchers have not identified those factors or the cause of the Fallon cluster, they said.
Scientists must determine the effect of variations in the SUOX gene and whether the variation makes it more or less likely that a child will get leukemia, they added.
The CDC said there is no existing data on what percentage of the overall U.S. population has the gene variation and whether the 40 percent figure among Fallon children tested for comparison is significant. That will be the subject of further study.
Rubin said good science has been generated as a result of the study of the Churchill County families.
"It would be wonderful for the families and all the researchers to have found a smoking gun," she said. "But what we're doing is good science, one step at a time, to get the answer."
Families of the leukemia victims, as well as the comparison families who gave blood, urine, DNA and personal information to the researchers in an effort to determine the cause of the leukemia cluster, were informed of the study's results on Wednesday.
Despite the uncertainty about the findings, the news was welcomed by Fallon resident Jeff Braccini, whose son, Jeremy, will be cancer-free for five years on Christmas Day.
"I'm really excited about the information," he said. "It's significant, very significant. We received a grant from (Nevada) Senator (Harry) Reid to do some studies, and now we are going to have to go back and re-evaluate what research we want to do."
Researchers and scientists agree that in cases of childhood leukemia, there first has to be a genetic predisposition to the disease and then an environmental factor to trigger the disease, Braccini said.
The fact that the variation in the gene is found both in the case and comparison group means that there is a new avenue to explore with the SUOX gene, he said.
"We're excited because good research leads to other good research," Braccini said.
A member of a group called Families in Search of the Truth, Braccini said the Fallon families won't stop until they find the cause of the terrible childhood illness.
Richard Jernee, who lost his son Adam to the disease at age 10 in 2001, said that what he has heard of the findings sounded encouraging, but he was still disappointed that more of an effort was not undertaken when most of the cases were discovered. Jernee, who now lives in College Place, Wash., said the genetic data, "is too little, too late."
"Ideally it would have been best if we had gotten the information years ago," said Jernee, who left Fallon about a year ago. "It's been too slow. If action had been initiated right away, it is possible we could have prevented other children from getting sick."
Jernee said the new information dredges up painful memories.
"It rattles me to the core," he said. "My little boy was a wonderful person. I miss him so much."
Reid also commented on the findings.
"The Centers for Disease Control believe that some of the data gathered warrants further investigation," he said.
"While the exact cause of the cancer cluster is still unknown, I remain committed to finding answers," Reid said. "We must continue our work to help those who have already been affected by the cluster and to protect future generations of Fallon families."
Rubin said a town hall meeting was not scheduled to announce the findings because the information did not warrant it. But all of the findings and information will be posted today on the agency's Web site and made available to the public and other researchers.
The samples were collected from 205 people in the fall of 2001, including 53 family members of many of the young people diagnosed with leukemia.
Rubin said the genetic testing was not performed until other issues, including environmental factors, were examined by the agency. Those results showed high levels of arsenic and the naturally occurring metal tungsten in the tested Fallon families, both those with and without leukemia.
Little is known about the effects of high levels of tungsten in people. Research on the issue is under way by the National Toxicology Program. The CDC did not find a correlation between arsenic and the leukemia cases.
The city of Fallon improved its water supply to eliminate arsenic, which also occurs naturally.
Rubin said the genetic information about SUOX will be forwarded to the National Toxicology Program for further study.
Once the environmental aspects of the research were concluded and reported, Rubin said, the agency, with outside help, identified 13 genes it wanted to examine to see whether there were variations between the case children and the comparison children.
The SUOX variation was the only significant finding of the study.
Genes direct the development and function of the body. More than 99.9 percent of the genetic instructions are the same for everyone. Only 0.1 percent vary. Usually the variations cause no harm. For example, genes that produce blue eyes are different from genes that produce brown eyes, but eye color does not affect how well a person sees. But sometimes a gene variation can increase a person's risk for a disease.
Rubin said that while the findings are not conclusive, the people of Churchill County who helped in the study have made a significant contribution to science.
"What has been found may contribute, hopefully, to moving this research forward until we do get an answer," she said.
Since 1997, 17 children with ties to Fallon have been diagnosed with leukemia. Three have died.
The last was a toddler reported in December 2004, two years after the 16th case was reported.
Health officials say about one case of the disease in five years would be expected.
CDC officials declined to comment on work by other researchers or on their theories about what caused the cluster in the small community 60 miles east of Reno.
