Genetics may reveal cause of cancer cluster

LITTLE ROCK - An Arkansas doctor is hoping a study of genetic factors reveals the cause of a cancer cluster in Fallon, Nev., that has sickened 16 children with leukemia since 2000, killing three.

The cause of the cluster is unknown despite exhaustive studies, including one by the Centers for Disease Control and Prevention that found higher-than-normal concentrations of arsenic, antimony, tungsten, cobalt and uranium in the northern Nevada town of 7,500. But the CDC found no single cause for the leukemias.

With $224,000 from the U.S. Environmental Protection Agency, Dr. Jill James of the Arkansas Children's Hospital Research Institute hopes to build on the CDC study and focus her work on any genetic causes for the cluster.

"We're interested in individual genetic profiles, whether they could interact with these metals to increase the cancer," James said. "All of the Fallon residents were exposed to the same stuff. What's different about the kids who got leukemia than the families who did not? What's changed, because these metals have presumably been there forever."

The reason the metals are interesting is because they all independently will cause damage to DNA. James said she's researching whether the metals combined reach a threshold that might trigger leukemia.

She also plans to look at the mothers of the children who had the disease, including their diet, genetics, and metabolism to see if the sick children were exposed to something before they were born.

"When a cancer occurs that early, there may be some prenatal exposure," James said. "Most cancers take time to develop. What we're really looking at is whether exposures during pregnancy could interact with the genetics."

The Arkansas researchers will take blood samples from the Fallon families with children who have leukemia and two control groups: One of Fallon families without health problems but who were also exposed to the metals and one of Arkansas families who have not been exposed to the metals.

The study is to begin by the end of the summer. James hopes to look at the genetic factors before the end of the year. Other aspects of the study might take longer, she said.

James said the CDC study may not have provided answers for the affected families because it was population-based. She hopes her individual-based research may provide the answers.

"We're coming in at the individual level to try to help, to at least help the families feel that the focus on them has been looked at," James said.

There are some problems with the individual approach though, James said.

"Unless we are really right about the genetic susceptibility factors and it just comes back really strong, we may not get statistical significance," James said.

U.S. Sen. Harry Reid, D-Nev., helped secure the money through the University of Nevada at Reno for James' study. The Arkansas research institute was chosen because of its work with cancer and birth defects.

"It is critically important to harness the expertise of outside specialists to investigate the cluster, and the retention of Dr. James is an important step in this effort," Reid said.

"The families deserve no less than the most skilled of eyes to find clues to the cause of the cluster."